A bacterial DNA topoisomerase II that catalyzes ATP-dependent breakage of both strands of DNA, passage of the unbroken strands through the breaks, and rejoining of the broken strands. Gyrase binds to DNA as a heterotetramer consisting of two A and two B subunits. In the presence of ATP, gyrase is able to convert the relaxed circular DNA duplex into a superhelix. In the absence of ATP, supercoiled DNA is relaxed by DNA gyrase.
DNA TOPOISOMERASES that catalyze ATP-dependent breakage of both strands of DNA, passage of the unbroken strands through the breaks, and rejoining of the broken strands. These enzymes bring about relaxation of the supercoiled DNA and resolution of a knotted circular DNA duplex.
An antibiotic compound derived from Streptomyces niveus. It has a chemical structure similar to coumarin. Novobiocin binds to DNA gyrase, and blocks adenosine triphosphatase (ATPase) activity. (From Reynolds, Martindale The Extra Pharmacopoeia, 30th ed, p189)
Circular duplex DNA isolated from viruses, bacteria and mitochondria in supercoiled or supertwisted form. This superhelical DNA is endowed with free energy. During transcription, the magnitude of RNA initiation is proportional to the DNA superhelicity.
COUMARINS with an amino group, exemplified by NOVOBIOCIN.
Synthetic antimicrobial related to NALIDIXIC ACID and used in URINARY TRACT INFECTIONS.
A bacterial DNA topoisomerase II that catalyzes ATP-dependent breakage of both strands of DNA, passage of the unbroken strands through the breaks, and rejoining of the broken strands. Topoisomerase IV binds to DNA as a heterotetramer consisting 2 parC and 2 parE subunits. Topoisomerase IV is a decatenating enzyme that resolves interlinked daughter chromosomes following DNA replication.
Compounds that inhibit the activity of DNA TOPOISOMERASE II. Included in this category are a variety of ANTINEOPLASTIC AGENTS which target the eukaryotic form of topoisomerase II and ANTIBACTERIAL AGENTS which target the prokaryotic form of topoisomerase II.
Synthetic or naturally occurring substances related to coumarin, the delta-lactone of coumarinic acid.
QUINOLONES containing a 4-oxo (a carbonyl in the para position to the nitrogen). They inhibit the A subunit of DNA GYRASE and are used as antimicrobials. Second generation 4-quinolones are also substituted with a 1-piperazinyl group at the 7-position and a fluorine at the 6-position.
DNA analogs containing neutral amide backbone linkages composed of aminoethyl glycine units instead of the usual phosphodiester linkage of deoxyribose groups. Peptide nucleic acids have high biological stability and higher affinity for complementary DNA or RNA sequences than analogous DNA oligomers.
A group of QUINOLONES with at least one fluorine atom and a piperazinyl group.
A group of derivatives of naphthyridine carboxylic acid, quinoline carboxylic acid, or NALIDIXIC ACID.
A synthetic 1,8-naphthyridine antimicrobial agent with a limited bacteriocidal spectrum. It is an inhibitor of the A subunit of bacterial DNA GYRASE.
A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.
DNA TOPOISOMERASES that catalyze ATP-independent breakage of one of the two strands of DNA, passage of the unbroken strand through the break, and rejoining of the broken strand. DNA Topoisomerases, Type I enzymes reduce the topological stress in the DNA structure by relaxing the superhelical turns and knotted rings in the DNA helix.
A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).
Deoxyribonucleic acid that makes up the genetic material of bacteria.
Double-stranded nucleic acid molecules (DNA-DNA or DNA-RNA) which contain regions of nucleotide mismatches (non-complementary). In vivo, these heteroduplexes can result from mutation or genetic recombination; in vitro, they are formed by nucleic acid hybridization. Electron microscopic analysis of the resulting heteroduplexes facilitates the mapping of regions of base sequence homology of nucleic acids.
The ability of microorganisms, especially bacteria, to resist or to become tolerant to chemotherapeutic agents, antimicrobial agents, or antibiotics. This resistance may be acquired through gene mutation or foreign DNA in transmissible plasmids (R FACTORS).
The spatial arrangement of the atoms of a nucleic acid or polynucleotide that results in its characteristic 3-dimensional shape.
The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.
Substances that prevent infectious agents or organisms from spreading or kill infectious agents in order to prevent the spread of infection.
Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.
Extrachromosomal, usually CIRCULAR DNA molecules that are self-replicating and transferable from one organism to another. They are found in a variety of bacterial, archaeal, fungal, algal, and plant species. They are used in GENETIC ENGINEERING as CLONING VECTORS.
Widely used technique which exploits the ability of complementary sequences in single-stranded DNAs or RNAs to pair with each other to form a double helix. Hybridization can take place between two complimentary DNA sequences, between a single-stranded DNA and a complementary RNA, or between two RNA sequences. The technique is used to detect and isolate specific sequences, measure homology, or define other characteristics of one or both strands. (Kendrew, Encyclopedia of Molecular Biology, 1994, p503)
The ability of bacteria to resist or to become tolerant to chemotherapeutic agents, antimicrobial agents, or antibiotics. This resistance may be acquired through gene mutation or foreign DNA in transmissible plasmids (R FACTORS).
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
Any tests that demonstrate the relative efficacy of different chemotherapeutic agents against specific microorganisms (i.e., bacteria, fungi, viruses).
Substances that reduce the growth or reproduction of BACTERIA.
Proteins found in any species of bacterium.
A polynucleotide consisting essentially of chains with a repeating backbone of phosphate and ribose units to which nitrogenous bases are attached. RNA is unique among biological macromolecules in that it can encode genetic information, serve as an abundant structural component of cells, and also possesses catalytic activity. (Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)
A synthetic fluoroquinolone antibacterial agent that inhibits the supercoiling activity of bacterial DNA GYRASE, halting DNA REPLICATION.
A synthetic fluoroquinolone (FLUOROQUINOLONES) with broad-spectrum antibacterial activity against most gram-negative and gram-positive bacteria. Norfloxacin inhibits bacterial DNA GYRASE.
The functional hereditary units of BACTERIA.
Enzymes that regulate the topology of DNA by actions such as breaking, relaxing, passing, and rejoining strands of DNA in cells. These enzymes are important components of the DNA replication system. They are classified by their substrate specificities. DNA TOPOISOMERASE I enzymes act on a single strand of DNA. DNA TOPOISOMERASE II enzymes act on double strands of DNA.
A broad-spectrum 6-fluoronaphthyridinone antibacterial agent that is structurally related to NALIDIXIC ACID.
A broad-spectrum antimicrobial carboxyfluoroquinoline.
A rigorously mathematical analysis of energy relationships (heat, work, temperature, and equilibrium). It describes systems whose states are determined by thermal parameters, such as temperature, in addition to mechanical and electromagnetic parameters. (From Hawley's Condensed Chemical Dictionary, 12th ed)
Compounds that inhibit the activity of DNA TOPOISOMERASES.
CIRCULAR DNA that is interlaced together as links in a chain. It is used as an assay for the activity of DNA TOPOISOMERASES. Catenated DNA is attached loop to loop in contrast to CONCATENATED DNA which is attached end to end.
5'-Adenylic acid, monoanhydride with imidodiphosphoric acid. An analog of ATP, in which the oxygen atom bridging the beta to the gamma phosphate is replaced by a nitrogen atom. It is a potent competitive inhibitor of soluble and membrane-bound mitochondrial ATPase and also inhibits ATP-dependent reactions of oxidative phosphorylation.
A synthetic broad-spectrum fluoroquinolone antibacterial agent active against most gram-negative and gram-positive bacteria.
The process by which a DNA molecule is duplicated.
A rapid-growing, nonphotochromogenic species of MYCOBACTERIUM originally isolated from human smegma and found also in soil and water. (From Dorland, 28th ed)
A group of enzymes which catalyze the hydrolysis of ATP. The hydrolysis reaction is usually coupled with another function such as transporting Ca(2+) across a membrane. These enzymes may be dependent on Ca(2+), Mg(2+), anions, H+, or DNA.
An adenine nucleotide containing three phosphate groups esterified to the sugar moiety. In addition to its crucial roles in metabolism adenosine triphosphate is a neurotransmitter.
The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.
The L-isomer of Ofloxacin.
A temperate coliphage, in the genus Mu-like viruses, family MYOVIRIDAE, composed of a linear, double-stranded molecule of DNA, which is able to insert itself randomly at any point on the host chromosome. It frequently causes a mutation by interrupting the continuity of the bacterial OPERON at the site of insertion.
Potentially pathogenic bacteria found in nasal membranes, skin, hair follicles, and perineum of warm-blooded animals. They may cause a wide range of infections and intoxications.
A genus of gram-positive, spherical bacteria found in soils and fresh water, and frequently on the skin of man and other animals.
Compounds that inhibit the activity of DNA TOPOISOMERASE I.
The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.
A gram-positive organism found in the upper respiratory tract, inflammatory exudates, and various body fluids of normal and/or diseased humans and, rarely, domestic animals.
A common inhabitant of the vagina and cervix and a potential human pathogen, causing infections of the male and female reproductive tracts. It has also been associated with respiratory disease and pharyngitis. (From Dorland, 28th ed)
Proteins obtained from ESCHERICHIA COLI.
Compounds or agents that combine with an enzyme in such a manner as to prevent the normal substrate-enzyme combination and the catalytic reaction.
A substituted dihydroxybenzene used topically as an antiseptic for the treatment of minor skin infections.
Any of the covalently closed DNA molecules found in bacteria, many viruses, mitochondria, plastids, and plasmids. Small, polydisperse circular DNA's have also been observed in a number of eukaryotic organisms and are suggested to have homology with chromosomal DNA and the capacity to be inserted into, and excised from, chromosomal DNA. It is a fragment of DNA formed by a process of looping out and deletion, containing a constant region of the mu heavy chain and the 3'-part of the mu switch region. Circular DNA is a normal product of rearrangement among gene segments encoding the variable regions of immunoglobulin light and heavy chains, as well as the T-cell receptor. (Riger et al., Glossary of Genetics, 5th ed & Segen, Dictionary of Modern Medicine, 1992)
Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.
Structures within the nucleus of bacterial cells consisting of or containing DNA, which carry genetic information essential to the cell.
A family of gram-negative bacteria in the order Methylophilales.
The parts of a macromolecule that directly participate in its specific combination with another molecule.
Electrophoresis in which agar or agarose gel is used as the diffusion medium.
The rate dynamics in chemical or physical systems.
Substances elaborated by specific strains of bacteria that are lethal against other strains of the same or related species. They are protein or lipopolysaccharide-protein complexes used in taxonomy studies of bacteria.
The concentration of a compound needed to reduce population growth of organisms, including eukaryotic cells, by 50% in vitro. Though often expressed to denote in vitro antibacterial activity, it is also used as a benchmark for cytotoxicity to eukaryotic cells in culture.
Compounds and molecular complexes that consist of very large numbers of atoms and are generally over 500 kDa in size. In biological systems macromolecular substances usually can be visualized using ELECTRON MICROSCOPY and are distinguished from ORGANELLES by the lack of a membrane structure.
The relationship between the chemical structure of a compound and its biological or pharmacological activity. Compounds are often classed together because they have structural characteristics in common including shape, size, stereochemical arrangement, and distribution of functional groups.
A plasmid whose presence in the cell, either extrachromosomal or integrated into the BACTERIAL CHROMOSOME, determines the "sex" of the bacterium, host chromosome mobilization, transfer via conjugation (CONJUGATION, GENETIC) of genetic material, and the formation of SEX PILI.
A genus in the family XANTHOMONADACEAE whose cells produce a yellow pigment (Gr. xanthos - yellow). It is pathogenic to plants.
The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.
Azoles of one NITROGEN and two double bonds that have aromatic chemical properties.
A multistage process that includes cloning, physical mapping, subcloning, determination of the DNA SEQUENCE, and information analysis.
Any compound that contains a constituent sugar, in which the hydroxyl group attached to the first carbon is substituted by an alcoholic, phenolic, or other group. They are named specifically for the sugar contained, such as glucoside (glucose), pentoside (pentose), fructoside (fructose), etc. Upon hydrolysis, a sugar and nonsugar component (aglycone) are formed. (From Dorland, 28th ed; From Miall's Dictionary of Chemistry, 5th ed)
A non-metabolizable galactose analog that induces expression of the LAC OPERON.
Any of the processes by which cytoplasmic or intercellular factors influence the differential control of gene action in bacteria.
The study of crystal structure using X-RAY DIFFRACTION techniques. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
A genus of bacteria that form a nonfragmented aerial mycelium. Many species have been identified with some being pathogenic. This genus is responsible for producing a majority of the ANTI-BACTERIAL AGENTS of practical value.
A species of gram-positive bacteria that is a common soil and water saprophyte.
In vitro method for producing large amounts of specific DNA or RNA fragments of defined length and sequence from small amounts of short oligonucleotide flanking sequences (primers). The essential steps include thermal denaturation of the double-stranded target molecules, annealing of the primers to their complementary sequences, and extension of the annealed primers by enzymatic synthesis with DNA polymerase. The reaction is efficient, specific, and extremely sensitive. Uses for the reaction include disease diagnosis, detection of difficult-to-isolate pathogens, mutation analysis, genetic testing, DNA sequencing, and analyzing evolutionary relationships.
Single chains of amino acids that are the units of multimeric PROTEINS. Multimeric proteins can be composed of identical or non-identical subunits. One or more monomeric subunits may compose a protomer which itself is a subunit structure of a larger assembly.
Chemicals with two conjoined aromatic rings incorporating two nitrogen atoms and one of the carbons oxidized with a keto oxygen.
A genus of aerobic, chemolithotrophic, coccoid ARCHAEA whose organisms are thermoacidophilic. Its cells are highly irregular in shape, often lobed, but occasionally spherical. It has worldwide distribution with organisms isolated from hot acidic soils and water. Sulfur is used as an energy source.
A species of extremely thermophilic, sulfur-reducing archaea. It grows at a maximum temperature of 95 degrees C. in marine or deep-sea geothermal areas.
Peptides whose amino and carboxy ends are linked together with a peptide bond forming a circular chain. Some of them are ANTI-INFECTIVE AGENTS. Some of them are biosynthesized non-ribosomally (PEPTIDE BIOSYNTHESIS, NON-RIBOSOMAL).
A genus of gram-positive, aerobic bacteria. Most species are free-living in soil and water, but the major habitat for some is the diseased tissue of warm-blooded hosts.
A temperate inducible phage and type species of the genus lambda-like viruses, in the family SIPHOVIRIDAE. Its natural host is E. coli K12. Its VIRION contains linear double-stranded DNA with single-stranded 12-base 5' sticky ends. The DNA circularizes on infection.
The level of protein structure in which combinations of secondary protein structures (alpha helices, beta sheets, loop regions, and motifs) pack together to form folded shapes called domains. Disulfide bridges between cysteines in two different parts of the polypeptide chain along with other interactions between the chains play a role in the formation and stabilization of tertiary structure. Small proteins usually consist of only one domain but larger proteins may contain a number of domains connected by segments of polypeptide chain which lack regular secondary structure.
The biosynthesis of RNA carried out on a template of DNA. The biosynthesis of DNA from an RNA template is called REVERSE TRANSCRIPTION.
Enzymes that catalyze either the racemization or epimerization of chiral centers within amino acids or derivatives. EC 5.1.1.
Proteins which bind to DNA. The family includes proteins which bind to both double- and single-stranded DNA and also includes specific DNA binding proteins in serum which can be used as markers for malignant diseases.
Ribonucleic acid in bacteria having regulatory and catalytic roles as well as involvement in protein synthesis.
The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.
A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts.
The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).
The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.
The naturally occurring or experimentally induced replacement of one or more AMINO ACIDS in a protein with another. If a functionally equivalent amino acid is substituted, the protein may retain wild-type activity. Substitution may also diminish, enhance, or eliminate protein function. Experimentally induced substitution is often used to study enzyme activities and binding site properties.
... conversion of the topoisomerase-quinolone-DNA complex to an irreversible form and (2) generation of a double-strand break by ... Norfloxacin does not bind to DNA gyrase but does bind to the substrate DNA. A review in 2001 suggests that cytotoxicity of ... "Mechanism of inhibition of DNA gyrase by analogues of nalidixic acid: the target of the drugs is DNA". Proc. Natl. Acad. Sci. U ... Drlica K, Zhao X (1 September 1997). "DNA gyrase, topoisomerase IV, and the 4-quinolones". Microbiol Mol Biol Rev. 61 (3): 377- ...
Like gyrase, topoisomerase IV is able to pass one double-strand of DNA through another double-strand of DNA, thereby changing ... The double-helical nature of DNA and its semiconservative mode of replication causes the two newly replicated DNA strands to be ... DNA gyrases are analogous enzymes in other organisms. While topoisomerase IV does relax positive supercoils like DNA gyrase, it ... It shares this role with DNA gyrase, which is also able to relax positive supercoils. Together, gyrase and topoisomerase IV ...
With the ligase activity disrupted, these enzymes release DNA with single- and double-strand breaks that lead to cell death. ... Specifically, they inhibit the ligase activity of the type II topoisomerases, DNA gyrase and topoisomerase IV, which cut DNA to ... "The effect of bacterial DNA gyrase inhibitors on DNA synthesis in mammalian mitochondria". Biochimica et Biophysica Acta (BBA ... For many Gram-negative bacteria, DNA gyrase is the target, whereas topoisomerase IV is the target for many Gram-positive ...
The net result is formation of two new double stranded DNA sequences that are exact copies of the original double stranded DNA ... Gyrase is most commonly found upstream of the replication fork, where the supercoils form. Single-stranded DNA is highly ... The replisome first unwinds double stranded DNA into two single strands. For each of the resulting single strands, a new ... DNA polymerase III DNA polymerase delta DNA polymerase epsilon This polymerase synthesizes leading and lagging strand DNA in ...
... inhibitors of DNA gyrase that cause double-strand breaks), bicyclomycin (causes single- and double-strand breaks), and ... a DNA damaging agent. In Helicobacter pylori, ciprofloxacin, which interacts with DNA gyrase and introduces double-strand ... is a key DNA repair process that is especially effective for repairing double-strand damages, such as double-strand breaks. ... and single-stranded DNA. In these protocols, the single-stranded DNA preferentially binds to the yeast cell wall, preventing ...
... helicases and gyrases (replication initiator proteins) uncoil the double-stranded DNA, exposing the nitrogenous bases. These ... forming a new double-stranded DNA molecule. This is known as semi-conservative replication since one strand of the new DNA ... causing thermal dissociation of the DNA strands. Two new cDNA strands are built from the original strand, these strands can be ... DNA replication also works by using a DNA template, the DNA double helix unwinds during replication, exposing unpaired bases ...
... end of the DNA. This creates a four-base overhang and a double-stranded break in the G-segment. As the DNA-binding gate ... The bending of DNA by gyrase has been proposed as a key mechanism in the ability of gyrase to introduce negative supercoils ... A strand of DNA, called the gate, or G-segment, is bound by a central DNA-binding gate (DNA-gate). A second strand of DNA, ... Both gyrase and topoisomerase IV CTDs bend DNA, but only gyrase introduces negative supercoils. Unlike the function of the C- ...
These topoisomerase-DNA-inhibitor complexes are cytotoxic agents, as the un-repaired single and double stranded DNA breaks that ... They also inhibit DNA gyrase's ability to bind to DNA instead of inhibiting ATPase activity, and produces several antibiotic ... 1989) model of quinolone inhibitor binding proposed that, in each DNAgyrase-DNA complex, four quinolone molecules associate ... TopII forms a homodimer that functions by cleaving double stranded DNA, winding a second DNA duplex through the gap, and re- ...
Mimitou, EP; Symington, LS (9 October 2008). "Sae2, Exo1 and Sgs1 collaborate in DNA double-strand break processing". Nature. ... a potential eukaryotic reverse gyrase". Molecular and Cellular Biology. 14 (12): 8391-8398. doi:10.1128/mcb.14.12.8391. PMC ... In particular, Sgs1 collaborates with other proteins to repair double-strand breaks during homologous recombination in ... Sgs1, also known as slow growth suppressor 1, is a DNA helicase protein found in Saccharomyces cerevisiae. It is a homolog of ...
On a next step the enzyme cleaves a G-segment of DNA (G- from gate) making a double-strand break. Then the T-segment is ... Upon binding to DNA (the "Gyrase-DNA" state), there is a competition between DNA wrapping and dissociation, where increasing ... whose single circular DNA is cut by DNA gyrase and the two ends are then twisted around each other to form supercoils. Gyrase ... DNA gyrase, or simply gyrase, is an enzyme within the class of topoisomerase and is a subclass of Type II topoisomerases that ...
... cut DNA in order to introduce supercoiling and with their ligase activity disrupted release DNA with single and double strand ... Quinolones inhibit the bacterial DNA gyrase or the topoisomerase IV enzyme, thereby inhibiting DNA replication and ... Castora, F. J.; Vissering, F. F.; Simpson, M. V. (September 1983). "The effect of bacterial DNA gyrase inhibitors on DNA ... Structure of bacterial DNA gyrase complexed with DNA and two ciprofloxacin molecules (green) ...
Single-Strand Binding (SSB) Proteins. Bind to ssDNA and prevent the DNA double helix from re-annealing after DNA helicase ... DNA Gyrase. Relieves strain of unwinding by DNA helicase; this is a specific type of topoisomerase ... Provides a starting point of RNA (or DNA) for DNA polymerase to begin synthesis of the new DNA strand. ... DNA Ligase. Re-anneals the semi-conservative strands and joins Okazaki Fragments of the lagging strand. ...
... type I produces transient single-strand breaks in DNA and types II produces transient double-strand breaks. As a result, the ... DNA gyrase preliminary role is to introduce negative super coils into DNA, thereby relaxing positive supercoils that come into ... In order for DNA replication to continue, single stranded binding proteins are needed to prevent the single strands of DNA from ... and opens up the double-stranded DNA for entrance of other replication proteins.[5] ...
... inhibitors of DNA gyrase that cause double-strand breaks), bicyclomycin (causes double-strand breaks), and hydroxyurea (causes ... These were mitomycin C (which introduces DNA inter-strand crosslinks), norfloxacin, ofloxacin, and nalidixic acid ( ... In order for a bacterium to bind, take up, and recombine exogenous DNA into its chromosome, it must enter a special ... In-depth comparative genome analysis using DNA arrays to study the gene content of 180 Legionella strains revealed high genome ...
... type I produces transient single-strand breaks in DNA and types II produces transient double-strand breaks. As a result, the ... DNA gyrase preliminary role is to introduce negative super coils into DNA, thereby relaxing positive supercoils that come into ... In order for DNA replication to continue, single stranded binding proteins are needed to prevent the single strands of DNA from ... The eukaryotic topo II, bacterial gyrase, and bacterial topo IV belong to the type II. We often forget that DNA gyrase does in ...
... inhibitors of DNA gyrase that produce double strand breaks), mitomycin C (which produces inter-strand cross-links), ... Dorer et al., in 2010, showed that ciprofloxacin, which interacts with DNA gyrase and causes production of double-strand breaks ... bind extracellular double stranded DNA. The DNA is then translocated across the membrane (or membranes for gram negative ... DNA uptake as a source of nucleotides (DNA as "food"); and (3) the selective advantage of a new strand of DNA to promote ...
In molecular biology Type I topoisomerases are enzymes that cut one of the two strands of double-stranded DNA, relax the strand ... except for reverse gyrase, which can introduce positive supercoils into DNA. DNA topoisomerases regulate the number of ... break single-strand DNA, and type II enzymes (EC; topoisomerases II, IV and VI) break double-strand DNA. Type IA topoisomerases ... or double-strand breaks, crossing the strands through one another, then resealing the breaks. DNA topoisomerases are divided ...
Double-stranded breaks in DNA can trigger incorrect DNA repair, chromosomal translocations, and in severe cases, DNA ... The cruciform structures can also disrupt a step in the kinetic pathway, shown when gyrase is inhibited by novobiocin. ... These biological implications range from affecting the supercoiling of DNA, causing double strand breaks in chromosomal DNA, ... Cruciform DNA is found in both prokaryotes and eukaryotes and has a role in DNA transcription and DNA replication, double ...
In circular DNA, in which double-helical DNA is bent around and joined in a circle, the two strands are topologically linked, ... E. coli contains four DNA topoisomerases: two type IA enzymes (I and III), and two type IIA (DNA gyrase and topoisomerase IV). ... The mitochondrial DNA of animal cells is a circular, double-stranded DNA that requires the activity of topoisomerase to be ... A type I topoisomerase cuts one strand of a DNA double helix, relaxation occurs, and then the cut strand is re-ligated. Cutting ...
DNA is made up of a double helix of two complementary strands. The double helix describes the appearance of a double-stranded ... including DNA gyrase) achieve this by adding negative supercoils to the DNA helix. Bare single-stranded DNA tends to fold back ... DNA exists as a double-stranded structure, with both strands coiled together to form the characteristic double-helix. Each ... must be created and paired with the template DNA strand. DNA polymerase adds a new strand of DNA by extending the 3′ end of an ...
... with the exception of phage HK022 The genome contains 48,490 base pairs of double-stranded, linear DNA, with 12-base single- ... Host DNA gyrase puts negative supercoils in the circular chromosome, causing A-T-rich regions to unwind and drive transcription ... The head contains the phage's double-strand linear DNA genome. During infection, the phage particle recognizes and binds to its ... The single-strand viral DNA ends are ligated by host DNA ligase. It is not generally appreciated that the 12 bp lambda cohesive ...
DMD DNA DNA bank DNA clone DNA cloning DNA fingerprint DNA glycosylase DNA gyrase DNA hybridization DNA ligase DNA marker DNA ... Double digest Double helix Double infection Double reduction Doublesex Down syndrome Downstream Draft sequence Duplicate gene ... Clone bank Cloned DNA Cloning Cloning vector Coccus Code Code dictionary Coding strand Codominance Codon Codon usage bias aka ... polymerase DNA probe DNA repair genes DNA replication DNA sequence DNA sequencing Docking protein Domain Dominance variance ...
... double-stranded DNA molecule that encodes the genetic information in a haploid form. The size of the DNA varies from 500,000 to ... with DNA gyrase and Topo I or DNA organization activities of HU such as DNA bending may facilitate or inhibit the action of DNA ... Examples of distorted DNA substrates include cruciform DNA, bulged DNA, dsDNA containing a single-stranded break such as nicks ... How does MatP condense DNA and promote DNA-DNA contacts? The experimental results are conflicting. MatP can form a DNA loop ...
Ashiuchi, M.; Kuwana, E; Yamamoto, T; Komatsu, K; Soda, K; Misono, H (2002). "Glutamate Racemase is an Endogenous DNA Gyrase ... Libonati, M; Bertoldi, M; Sorrentino, S (1996). "The activity on double-stranded RNA of aggregates of ribonuclease a higher ... Racemization and DNA gyrase inhibition are two independent activities of the enzyme". Microbiology. 154 (9): 2796-803. doi: ... Deprez, E.; Tauc, P.; Leh, H.; Mouscadet, J.-F.; Auclair, C.; Hawkins, M. E.; Brochon, J.-C. (2001). "DNA binding induces ...
It is responsible for metabolizing both single stranded DNA (ssDNA) and double stranded DNA (dsDNA) with mismatched 3' ends and ... DNA clamp. *Topoisomerase *DNA gyrase. *Prokaryotic DNA polymerase: DNA polymerase I *Klenow fragment ... The ε subunit is one of three core proteins in the DNA polymerase complex. It functions as a 3'→5' DNA directed proofreading ... proving that the epsilon subunit has an essential function in DNA editing and preventing the initiation of SOS DNA repair.[5] ...
There are two genes in Sulfolobus that each encode a reverse gyrase. It is defined atypical Dna topoisomerases and the basic ... Guagliardi A, Napoli A, Rossi M, Ciaramella M (April 1997). "Annealing of complementary DNA strands above the melting point of ... Sulfolobus strains present different peculiar DNA binding proteins, such as the Sso7d protein family. They stabilize the double ... of the OB domain of the single stranded DNA binding protein from Sulfolobus solfataricus and chemical shift mapping of the DNA- ...
Within cells, the long strands of DNA form condensed structures called chromosomes. The specific location of a DNA sequence ... Indeed, chromosome doubling within a species may be a common cause of reproductive isolation, as half the doubled chromosomes ... Fluoroquinolone Resistance in Pseudomonas aeruginosa Due to Interplay of the MexAB-OprM Efflux Pump and the DNA Gyrase Mutation ... Recombination allows alleles on the same strand of DNA to become separated. However, the rate of recombination is low ( ...
"Genetic Variants That Predispose to DNA Double-Strand Breaks in Lymphocytes From a Subset of Patients With Familial Colorectal ... DNA clamp. *Topoisomerase *DNA gyrase. *Prokaryotic DNA polymerase: DNA polymerase I *Klenow fragment ... DNA damage response, detection of DNA damage. • nucleotide-excision repair, DNA incision, 5'-to lesion. • DNA ligation. • DNA ... nucleotide-excision repair, DNA gap filling. • DNA synthesis involved in DNA repair. • cellular response to UV. • DNA ...
A type II topoisomerase that negatively supercoils closed circular double-stranded (ds) DNA in an ATP-dependent manner to ... Negative supercoiling favors strand separation, and DNA replication, transcription, recombination and repair, all of which ... Type II topoisomerases break and join 2 DNA strands simultaneously in an ATP-dependent manner. UniProt ... In the heterotetramer, GyrA contains the active site tyrosine that forms a transient covalent intermediate with DNA, while GyrB ...
Negative supercoiling favors strand separation, and DNA replication, transcription, recombination and repair, all of which ... Type II topoisomerases break and join 2 DNA strands simultaneously in an ATP-dependent manner. ... DNA in an ATP-dependent manner to modulate DNA topology and maintain chromosomes in an underwound state. ... involve strand separation. Also able to catalyze the interconversion of other topological isomers of dsDNA rings, including ...
... it inhibits relaxation of supercoiled DNA and promotes breakage of double-stranded DNA. Continue treatment for at least 2 d ... This agent inhibits bacterial DNA gyrase and consequently growth; ... Prospective randomized double blind placebo-controlled evaluation of azithromycin for treatment of cat-scratch disease. Pediatr ... Rifampin inhibits bacterial RNA synthesis by binding to the beta subunit of DNA-dependent RNA polymerase, blocking RNA ...
promotion of double-stranded DNA breakage.. The fluorine atom at the 6 position provides increased potency against gram- ... inhibition of the ATP-dependent DNA supercoiling reaction catalyzed by DNA gyrase, ... Although norfloxacin was weakly positive in the Rec-assay for DNA repair, all other mutagenic assays were negative including a ... while participating in a double-blind, crossover study comparing single doses of norfloxacin with placebo. While crystalluria ...
These include: high selectivity for binding of G-quadruplex DNA over double stranded DNA; inhibition of both DNA gyrase and ...
CcdB acts on gyrase in a similar way as quinolones do, both compounds induce double-strand breaks in DNA. Interestingly, the ... The ccd poison/antidote system of the F plasmid encodes CcdB, a toxin targeting the essential DNA gyrase of E. coli, and CcdA, ... Molecular interactions of the CcdB poison with its bacterial target, the DNA gyrase.. Van Melderen L1. ... Gyrase belongs to the topoisomerase II class of enzymes and is a well-validated target for efficient therapeutic drugs, i. e. ...
Ciprofloxacin: Fluoroquinolone antibiotic; inhibits DNA gyrase; promotes breakage of double-stranded DNA; bactericidal ...
The role of DNA gyrase -a type II topoisomerase- had been speculated about for a long time before the discovery of the enzyme. ... In 1963, J. Cairns (1) pointed out that the Escherichia coli chromosome is a closed circular double strand DNA molecule. It has ... Orr E., Lother H., Lurz R., Wahle E. (1984) Escherichia coli DNA Gyrase. In: Proteins Involved in DNA Replication. Advances in ... all dependent on the DNA template. DNA gyrase has now become a most promiscuous protein, participating in different molecular ...
Nalidixic acid survival assay.Nalidixic acid (Nal) causes DNA double-strand breaks by partially inhibiting DNA gyrase (10, 29 ... Since it is thought that the RecBCD pathway acts at double-strand DNA breaks and the RecF pathway acts at single-strand DNA ... Nalidixic acid has been shown in E. coli to produce double-strand breaks in DNA by inhibiting the ligation function of gyrase ( ... Conversion of phiX174 viral DNA to double-stranded form by purified Escherichia coli proteins. Proc. Natl. Acad. Sci. USA71: ...
On a next step the enzyme cleaves a G-segment of DNA (G- from gate) making a double-strand break. Then the T-segment is ... Upon binding to DNA (the "Gyrase-DNA" state), there is a competition between DNA wrapping and dissociation, where increasing ... whose single circular DNA is cut by DNA gyrase and the two ends are then twisted around each other to form supercoils. Gyrase ... DNA gyrase, or simply gyrase, is an enzyme within the class of topoisomerase and is a subclass of Type II topoisomerases that ...
DNA gyrase explanation free. What is DNA gyrase? Meaning of DNA gyrase medical term. What does DNA gyrase mean? ... Looking for online definition of DNA gyrase in the Medical Dictionary? ... single-stranded DNA. produced when double-stranded DNA is denatured or found naturally in some viruses. ... Related to DNA gyrase: Topoisomerase, Quinolones. DNA gyrase. (ji´rās) a type II DNA topoisomerase.. DNA gyrase. an enzyme that ...
... closed-circular DNA, according to the Critical Review of Biochemical and Molecular Biology.... ... DNA gyrase is a bacterial enzyme that catalyzes the ATP-dependent negative supercoiling of double-stranded, ... DNA gyrase is a bacterial enzyme that catalyzes the ATP-dependent negative supercoiling of double-stranded, closed-circular DNA ... Review of Biochemical and Molecular Biology states that DNA gyrase relieves strain while helicase unwinds double-strand DNA. ...
The double-strand DNA sequence of the 5′ gyrA region and the deduced amino acid sequence are shown. ... These physiological effects made the bacterial type II DNA topoisomerases, DNA gyrase (gyrase) and DNA topoisomerase IV (topo ... The enzyme introduces negative supercoils into DNA by wrapping DNA around the A2B2 protein complex, cleaving both DNA strands ( ... 1987) Cloning and sequencing of the Escherichia coli DNA gyrA gene coding for the A subunit of DNA gyrase. J. Mol. Biol. 197: ...
Norfloxacin-induced DNA gyrase cleavage complexes block Escherichia coli replication forks, causing double-stranded breaks in ... DNA strand cleavage is required for replication fork arrest by a frozen topoisomerase-quinolone-DNA ternary complex. J Biol ... Covalent protein-DNA adducts or tightly bound proteins represent a major challenge to the DNA replication machinery. DNA ... However, such double-circle RCs could have enormously long intervening linear DNA after RC replication, making them difficult ...
DNA Replication, Mutation, and Repair - Free download as Powerpoint Presentation (.ppt), PDF File (.pdf), Text File (.txt) or ... DNA gyrase - this is a topoisomerase II, which. breaks and reseals double-stranded DNA to introduce. negative supercoils ahead ... G dna B (helicase). B C dna C. dna G (primase). template strand. 5 3. 3 OH 5. RNA primer. (~5 nucleotides). DNA ... template for a daughter strand. Daughter DNA strands. Origins of DNA replication on mammalian chromosomes. origins of DNA ...
... this level of inhibition causes a fivefold-greater accumulation of single-strand DNA nicks than of double-strand DNA breaks (35 ... caused by a subset of drug-enzyme-DNA complexes or possibly by complexes in which single-strand rather than double-strand DNA ... the killing of cells but not the blocking of DNA replication may be affected by the repair of DNA double-strand breaks. ... 1996) DNA gyrase and topoisomerase IV on the bacterial chromosome: quinolone-induced DNA cleavage. J. Mol. Biol. 258:627-637. ...
... break double-strand DNA [PMID: 12596227].. Type I topoisomerases are ATP-independent enzymes (except for reverse gyrase), and ... DNA topoisomerases regulate the number of topological links between two DNA strands (i.e. change the number of superhelical ... Topo IB enzymes do not require a single-stranded region of DNA or metal ions for their function. The type IB family of DNA ... or double-strand breaks, crossing the strands through one another, then resealing the breaks [PMID: 7770916]. These enzymes ...
The peptide antibiotic microcin B17 induces double-strand cleavage of DNA mediated by E. coli DNA gyrase. EMBO J. 10 1991 467 ... other microcins provide antimicrobial action by inhibiting DNA gyrase, by inhibiting protein expression (17, 21), or by forming ... The export of the DNA replication inhibitor microcin B17 provides immunity for the host cell. EMBO J. 7 1988 1853 1862 ... Integrons: novel DNA elements which capture genes by site-specific recombination. Genetica 90 1993 115 132 ...
DNA gyrase and topoisomerase IV, and induce them to kill cells by generating high levels of double-stranded DNA breaks. A ... Keywords: Amscrine; Antineoplastic Quinolones; E. Coli DNA Gyrase; Etoposide; Eukaryotic Topoisomerase II; Human Topoisomerase ... Depending upon the bacterial species and quinolone employed, either DNA gyrase or topoisomerase IV serves as the primary ...
At higher drug concentrations, cell death occurs as double-strand DNA breaks are released from trapped gyrase and/or ... The key event in quinolone action is reversible trapping of gyrase-DNA and topoisomerase IV-DNA complexes. Complex formation ... DNA gyrase, topoisomerase IV, and the 4-quinolones. Message Subject (Your Name) has forwarded a page to you from Microbiology ... Gyrase is also trapped on DNA by lethal gene products of certain large, low-copy-number plasmids. Thus, quinolone-topoisomerase ...
The Escherichia coli chromosome is a 4.6-Mbp circular double-stranded (ds) DNA duplex, in which the two DNA strands are wrapped ... During replication, DNA gyrase acts to remove the majority of these strand crossings, but those that remain result in two ... Of includes all DNA outside the complex. For simplicity, let O = Of + Ob. Cleavage and strand exchange occur inside the tangle ... When the DNA substrate consists of circular DNA molecules, the recombination sites may occur in a single DNA circle or in ...
With the ligase activity disrupted, these enzymes release DNA with single- and double-strand breaks that lead to cell death. ... Specifically, they inhibit the ligase activity of the type II topoisomerases, DNA gyrase and topoisomerase IV, which cut DNA to ... "The effect of bacterial DNA gyrase inhibitors on DNA synthesis in mammalian mitochondria". Biochimica et Biophysica Acta (BBA ... For many Gram-negative bacteria, DNA gyrase is the target, whereas topoisomerase IV is the target for many Gram-positive ...
DNA incorporation of oxidized nucleotides can lead to double-strand breaks (25, 32), which may be redundant with the primary ... 2007) Gyrase inhibitors induce an oxidative damage cellular death pathway in Escherichia coli. Mol Syst Biol 3(91):1-15. ... oxidation following ROS formation and that the subsequent incorporation of these nucleotides into DNA leads to double-strand ... Antibiotic-induced ROS damage DNA nucleotides. Overexpression of the DNA mismatch repair protein MutS inhibits killing by ...
DNA gyrase action involves the introduction of transient double-strand breaks into DNA. Proc. Natl. Acad. Sci. USA77:1847-1851. ... Quinolone-DNA interaction: sequence-dependent binding to single-stranded DNA reflects the interaction within the gyrase-DNA ... Step a) Binding of gyrase to DNA. (Step b) Reversible formation of quinolone-gyrase-DNA complexes that rapidly block DNA ... Norfloxacin-induced DNA gyrase cleavage complexes block Escherichia coli replication forks, causing double-stranded breaks in ...
Gyrase and topoisomerase IV create transient double-stranded breaks in the genetic material in order to carry out their ... Finally, it will discuss recent experiments with novel naphthyridone-based drugs that alter gyrase-mediated DNA cleavage by a ... Quinolones take advantage of this enzyme-mediated DNA cleavage activity and kill cells by converting gyrase and topoisomerase ... Quinolones target the bacterial type II topoisomerases, gyrase and topoisomerase IV. These enzymes regulate DNA under- and over ...
Inhibitors of DNA Synthesis or Integrity , Adjunctive and Prophylactic Use of Antibacterial Agents in Dentistry , CE Course on ... must replicate their double stranded DNA. To facilitate replication, topoisomerase type II, a bacterial DNA gyrase, must first ... One of its metabolite directly binds to bacterial DNA, causes loss of its helical structure, and effects strand breakage.50,60, ... Inhibitors of DNA Synthesis or Integrity Cell wall inhibitors cannot kill all bacteria because some bacteria lack a cell wall. ...
Článek A single Ho-induced double-strand break at the MAT locus is lethal in Candida glabrata ... In bacteria, global DNA supercoiling results from the opposing activities of topoisomerase I, which relaxes DNA, and DNA gyrase ... DNA supercoiling differences in bacteria result from disparate DNA gyrase activation by polyamines English version ... DNA gyrase: an enzyme that introduces superhelical turns into DNA. Proc Natl Acad Sci. 1976;73:3872-3876. doi: 10.1073/pnas. ...
The response to local changes induced by fluoroquinolone antibiotics, which target DNA gyrase subunit A and/or topoisomerase IV ... The response to local changes induced by fluoroquinolone antibiotics, which target DNA gyrase subunit A and/or topoisomerase IV ... DNA-supercoiling is homeostatically maintained by the opposing activities of relaxing DNA topoisomerases and negative supercoil ... DNA gyrase. DNA-supercoiling acts as a general cis regulator of transcription, which can be superimposed upon other types of ...
... break single-strand DNA, and type II enzymes (EC:5.99.1.3; topoisomerases II, IV and VI) break double-strand DNA [PMID: ... topoisomerase II or gyrase, and topoisomerase IV) and type IIB (topoisomerase VI). These enzymes are responsible for relaxing ... DNA topoisomerases regulate the number of topological links between two DNA strands (i.e. change the number of superhelical ... GO:0006265 DNA topological change Molecular Function. GO:0005524 ATP binding GO:0003677 DNA binding GO:0003918 DNA ...
Newly synthesized DNA strand is recognized. - Mismatched nucleotides are removed. - Gap is filled & resealed ... Create single or double strand break in helix to relieve supercoiling 15 ... RNA-dependent DNA polymerase that adds DNA to 3 ends of chromosomes to avoid loss of genetic material during replication ... Y-shaped region along DNA template where leading & lagging strands are synthesized ...
  • Rifampin inhibits bacterial RNA synthesis by binding to the beta subunit of DNA-dependent RNA polymerase, blocking RNA transcription. (medscape.com)
  • The gene encoding the DNA gyrase A subunit of Streptococcus pneumoniae was cloned and sequenced. (asm.org)
  • The gyrA gene codes for a protein of 822 amino acids homologous to the gyrase A subunit of eubacteria. (asm.org)
  • The A subunit is required for the double-stranded breakage and reunion of DNA ( 41 ), and the B subunit is required for energy transduction via ATP hydrolysis ( 25 , 40 ). (asm.org)
  • Two classes of antibiotics that inhibit gyrase are: The aminocoumarins (including novobiocin and Coumermycin A1), which work by competitive inhibition of energy transduction of DNA gyrase by binding to the ATPase active site on the GyrB subunit. (wikipedia.org)
  • The response to local changes induced by fluoroquinolone antibiotics, which target DNA gyrase subunit A and/or topoisomerase IV, involves an increase in oxygen radicals which reduces cell viability, while the induction of global supercoiling changes by novobiocin (a DNA gyrase subunit B inhibitor), or by seconeolitsine (a topoisomerase I inhibitor), has revealed the existence of topological domains that specifically respond to such changes. (frontiersin.org)
  • The FQs bind primarily to the GyrA subunit of mycobacterial gyrase, while in E. coli holoenzyme is the target. (embl.de)
  • Aminocoumarins are very potent inhibitors of bacterial DNA gyrase and work by inhibiting the GyrB subunit of the enzyme involved in energy tranduction. (drugbank.ca)
  • This entry represents subunit A (gyrA and parC) of bacterial gyrase and topoisomerase IV, and the equivalent C-terminal region in eukaryotic topoisomerase II composed of a single polypeptide. (embl.de)
  • This subunit has DNA-binding capacity. (embl.de)
  • Nicking of double stranded DNA (subunit A). (gpatcrackers.com)
  • Negative recoiling when the two strands separate to replicate and transcript (subunit B). (gpatcrackers.com)
  • Fluroquinolones inhibits subunit A of DNA gyrase. (gpatcrackers.com)
  • Ciprofloxacin binds to A subunit of DNA gyrase and interfere with its strand cutting and resealing function. (rx2go.com)
  • Type II topoisomerases break and join 2 DNA strands simultaneously in an ATP-dependent manner. (rcsb.org)
  • Also referred to as topoisomerases, gyrase is a member of a category of enzymes that control the topological transitions of DNA. (reference.com)
  • DNA topoisomerases control bacterial DNA topology, which is implicated in the processes of DNA replication, recombination, and transcription. (asm.org)
  • These physiological effects made the bacterial type II DNA topoisomerases, DNA gyrase (gyrase) and DNA topoisomerase IV (topo IV), essential for cell viability. (asm.org)
  • DNA gyrase, or simply gyrase, is an enzyme within the class of topoisomerase and is a subclass of Type II topoisomerases that reduces topological strain in an ATP dependent manner while double-stranded DNA is being unwound by elongating RNA-polymerase or by helicase in front of the progressing replication fork. (wikipedia.org)
  • DNA topoisomerases regulate the number of topological links between two DNA strands (i.e. change the number of superhelical turns) by catalysing transient single- or double-strand breaks, crossing the strands through one another, then resealing the breaks [ PMID: 7770916 ]. (ebi.ac.uk)
  • topoisomerases II, IV and VI) break double-strand DNA [ PMID: 12596227 ]. (ebi.ac.uk)
  • The type IB family of DNA topoisomerases includes eukaryotic nuclear topoisomerase I, topoisomerases of poxviruses, and bacterial versions of Topo IB [ PMID: 17293019 ]. (ebi.ac.uk)
  • The mechanisms of DNA topoisomerases. (ebi.ac.uk)
  • Cellular roles of DNA topoisomerases: a molecular perspective. (ebi.ac.uk)
  • DNA topoisomerases: structure, function, and mechanism. (ebi.ac.uk)
  • Phylogenomics of type II DNA topoisomerases. (ebi.ac.uk)
  • Origin and evolution of DNA topoisomerases. (ebi.ac.uk)
  • The structure and mechanism of the action of type-IB DNA topoisomerases]. (ebi.ac.uk)
  • The intracellular targets of the quinolones are two DNA topoisomerases: gyrase and topoisomerase IV. (asm.org)
  • After drug binding, a slower, DNA cleavage-associated step occurs ( 35 ) that results in drug-mediated inhibition of religation of the DNA ends by topoisomerases ( 1 ). (asm.org)
  • In a sense, quinolones trap the bacterial type II topoisomerases on DNA ( 17 , 23 , 73 , 75 ) (Fig. 1 , step b 2 ). (asm.org)
  • Dr. Osheroff's research focuses on topoisomerases, enzymes that remove knots and tangles from the genetic material and modulate torsional stress in DNA. (bioconferencelive.com)
  • Quinolones target the bacterial type II topoisomerases, gyrase and topoisomerase IV. (bioconferencelive.com)
  • Roles of Topoisomerases in Maintaining Steady-state DNA Supercoiling in Escherichia coli. (prolekare.cz)
  • DNA-supercoiling is homeostatically maintained by the opposing activities of relaxing DNA topoisomerases and negative supercoil-inducing DNA gyrase. (frontiersin.org)
  • The control of DNA-supercoiling in S. pneumoniae occurs mainly via the regulation of topoisomerase gene transcription: relaxation triggers the up-regulation of gyrase and the down-regulation of topoisomerases I and IV, while hypernegative supercoiling down-regulates the expression of topoisomerase I. Relaxation affects 13% of the genome, with the majority of the genes affected located in 15 domains. (frontiersin.org)
  • Type II topoisomerases are ATP-dependent enzymes, and can be subdivided according to their structure and reaction mechanisms: type IIA (topoisomerase II or gyrase, and topoisomerase IV) and type IIB (topoisomerase VI). (ebi.ac.uk)
  • Structure and function of type II DNA topoisomerases. (ebi.ac.uk)
  • Topoisomerases serve as critical enzymes that resolve topological problems during DNA synthesis, transcription, and repair. (embl.de)
  • DNA topoisomerases are essential enzymes that control the topological state of DNA replication during mitosis. (ejbiotechnology.info)
  • During mitosis, superhelical DNA must be unwound or relaxed by DNA topoisomerases prior to a decoding step by DNA processing enzymes, such as DNA polymerase and RNA polymerase. (ejbiotechnology.info)
  • DNA topoisomerases are found in nature and used as high quality and well-validated targets for the screening of potential anticancer agents. (ejbiotechnology.info)
  • Our current work focuses on determining potential anticancer agents from natural resources using DNA topoisomerases as the screening targets. (ejbiotechnology.info)
  • DNA topoisomerases are essential enzymes that control the topological state of DNA during cellular processes in both prokaryotic and eukaryotic cells. (ejbiotechnology.info)
  • The types of organisms used in the studies of DNA topoisomerases include Escherichia coli , Staphylococcus aureus , yeasts, plants from the genus Arabidopsis , flies from the genus Drosophila and human. (ejbiotechnology.info)
  • Several viruses, such as bacteriophage T4 and animal vaccinia viruses, can also encode DNA topoisomerases. (ejbiotechnology.info)
  • Bacterial type II topoisomerases (DNA gyrase and Topoisomerase-IV) are the targets of quinolone antibiotics. (tcichemicals.com)
  • Vaccinia virus , a cytoplasmically-replicating poxvirus, encodes a type I DNA topoisomerase that is biochemically similar to eukaryotic-like DNA topoisomerases I, and which has been widely studied as a model topoisomerase. (xfam.org)
  • DNA topoisomerases are double-stranded and helical in nature [ 1 ]. (ijddr.in)
  • One of the type II topoisomerases involved in the supercoiling of double-stranded circular DNA molecules. (lymphedemapeople.com)
  • Clerocidin (CL), a microbial diterpenoid, reacts with DNA via its epoxide group and stimulates DNA cleavage by type II DNA topoisomerases. (nih.gov)
  • Type II topoisomerases CC break and join 2 DNA strands simultaneously in an ATP-dependent CC manner. (genome.jp)
  • Ciprofloxacin HCl targets gyrases and topoisomerases inhibiting DNA unwinding. (thewisearticles.com)
  • This entry describes the DNA-binding domain (domain 3) found in type IA topoisomerases. (embl-heidelberg.de)
  • The structures of bacterial topoisomerases I and III have been shown to consist of four domains that together form a toroidal structure with a central hole large enough to accommodate single- and double-stranded DNA. (embl-heidelberg.de)
  • DNA topoisomerases. (embl-heidelberg.de)
  • In the past year, the atomic structures of three fragments of type I DNA topoisomerases were elucidated. (embl-heidelberg.de)
  • Together with the atomic structure of a fragment of bacterial gyrase, this wealth of structural information is helping to further our understanding of the mechanism of action of topoisomerases. (embl-heidelberg.de)
  • Interference with these two topoisomerases results in strand breakage of the bacterial chromosome, supercoiling, and resealing. (drugbank.com)
  • Quinolones bind rapidly to the DNA topoisomerases attached to DNA, producing ternary complexes comprising quinolone-topoisomerase-DNA. (beds.ac.uk)
  • Fluoroquinolone-class agents selectively target the bacterial type IIA topoisomerases DNA gyrase and topoisomerase IV, with a few exceptions that target eukaryotic type IIA topoisomerases. (nebraska.edu)
  • The role of DNA gyrase -a type II topoisomerase- had been speculated about for a long time before the discovery of the enzyme. (springer.com)
  • an enzyme that nicks and seals the DNA and relieves supercoiling. (thefreedictionary.com)
  • DNA gyrase is a bacterial enzyme that catalyzes the ATP-dependent negative supercoiling of double-stranded, closed-circular DNA, according to the Critical Review of Biochemical and Molecular Biology. (reference.com)
  • The enzyme introduces negative supercoils into DNA by wrapping DNA around the A 2 B 2 protein complex, cleaving both DNA strands (which involves the formation of DNA-protein covalent bonds) and using ATP hydrolysis to pass another portion of DNA through this break. (asm.org)
  • The enzyme causes negative supercoiling of the DNA or relaxes positive supercoils. (wikipedia.org)
  • The helical nature of the DNA causes positive supercoils to accumulate ahead of a translocating enzyme, in the case of DNA replication, a DNA polymerase. (wikipedia.org)
  • DNA gyrase is a tetrameric enzyme that consists of 2 GyrA ("A") and 2 GyrB ("B") subunits. (wikipedia.org)
  • On a next step the enzyme cleaves a G-segment of DNA (G- from gate) making a double-strand break. (wikipedia.org)
  • DNA-gyrase ligates the break in a G-segment back and T-segment finally leaves the enzyme complex. (wikipedia.org)
  • The gyrase motif reflects wrapping of DNA around the enzyme complex and DNA flexibility. (wikipedia.org)
  • The key step in quinolone action is trapping gyrase or topoisomerase IV on DNA as ternary drug-enzyme-DNA complexes (reviewed in reference 10 ). (asm.org)
  • This finding suggests that the inhibition of DNA synthesis and cell growth is caused by a subset of drug-enzyme-DNA complexes or possibly by complexes in which single-strand rather than double-strand DNA breaks occurred. (asm.org)
  • the covalent protein-DNA linkage is then reversed and the enzyme dissociates from the DNA ( 5 ). (aacrjournals.org)
  • In the present study we refer to them as cleaved complexes to emphasize that phosphodiester bonds in the DNA moiety are broken (the term ternary complex is reserved for the early step in drug-enzyme-DNA complex formation in which the DNA is unbroken). (asm.org)
  • Quinolones take advantage of this enzyme-mediated DNA cleavage activity and kill cells by converting gyrase and topoisomerase IV, into toxic "nucleases" that fragment the bacterial chromosome. (bioconferencelive.com)
  • In vitro , Salmonella DNA gyrase activity was sensitive to changes in putrescine concentration within the physiological range, whereas activity of the E . coli enzyme was not. (prolekare.cz)
  • In vivo , putrescine activated the Salmonella DNA gyrase and spermidine the E . coli enzyme. (prolekare.cz)
  • DNA gyrase: an enzyme that introduces superhelical turns into DNA. (prolekare.cz)
  • This region also contains four "GATC" sequences that are recognized by DNA adenine methylase (Dam), an enzyme that modifies the adenine base when this sequence is unmethylated or hemimethylated. (wikipedia.org)
  • Fluoroquinolones (FQs), successful as drugs clinically, target the enzyme to trap the gyrase-DNA complex, leading to the accumulation of double-strand breaks in the genome. (embl.de)
  • DNA gyrase-targeting pentapeptide repeat proteins can both inhibit DNA gyrase-a potentially useful therapeutic property-and contribute to resistance to quinolone antibacterials (by acting to prevent them forming a lethal complex with the DNA and enzyme). (embl.de)
  • Etoposide interferes with DNA synthesis by inhibiting the enzyme topoisomerase-II. (tcichemicals.com)
  • The crystal structures of human topoisomerase I comprising the core and carboxyl-terminal domains in covalent and noncovalent complexes with 22-base pair DNA duplexes reveal an enzyme that "clamps" around essentially B-form DNA. (xfam.org)
  • The core domain and the first eight residues of the carboxyl-terminal domain of the enzyme, including the active-site nucleophile tyrosine-723, share significant structural similarity with the bacteriophage family of DNA integrases. (xfam.org)
  • During the process of DNA replication, the strands are unwound by an enzyme called DNA helicase, and a new strand of DNA is synthesized on each of the old ( template ) strands by an enzyme called DNA polymerase, which joins incoming nucleotides together in a sequence that is determined by the sequence of nucleotides present in the template strand. (encyclopedia.com)
  • In prokaryotes, the particular form of the enzyme is called DNA polymerase III. (encyclopedia.com)
  • DNA gyrase is an enzyme that relieves the strain caused by helicase, as it unwinds the DNA during bacteria replication. (icd10monitor.com)
  • Topoisomerase IV is an enzyme that unlinks DNA following replication and also relieves the strain caused by helicase. (icd10monitor.com)
  • An enzyme with bound DNA can admit a second DNA duplex through one set of jaws, transport it through the cleaved first duplex, and expel it through the other set of jaws. (embl-heidelberg.de)
  • Crystal structures of gepotidacin with gyrase and nicked or intact DNA revealed details of the compound's interaction with the enzyme and DNA. (vumc.org)
  • For most of the processes individual DNA strand is required to be separated either temporarily (by transcription), or permanently (by replication).The topological alterations of DNA are catalyzed by topoisomerase enzyme for essential cellular functions [ 2 ]. (ijddr.in)
  • Two years ago, in 1956, I successfully isolated the first DNA polymerizing enzyme. (philome.la)
  • After I isolated this enzyme I successfully synthesized DNA in a test tube and my colleague Servo Ochoa synthesized RNA. (philome.la)
  • Two molecules of the enzyme helicase bind to the initiator proteins and move along the strands in each direction, separating the strands. (sunyorange.edu)
  • Copy DNA DNA transcribed from a specific RNA through the action of the enzyme reverse transcriptase. (lymphedemapeople.com)
  • By blocking bacterial DNA replication trough binding itself to an enzyme called DNA gyrase, thereby causing double-stranded breaks in the bacterial chromosome. (sahilpharmagroup.com)
  • DNA gyrase (an enzyme) makes a cut in the double helix of and each side separates like unzipping a zipper. (wyzant.com)
  • Helicase (an enzyme) causes the the double strand of DNA to unwind into its rope ladder appearance. (wyzant.com)
  • DNA polymerase (an enzyme complex) "walks" down the strand and adds new nucleotides to each strand. (wyzant.com)
  • DNA ligase (an enzyme) seals up the fragments into one continuous strand. (wyzant.com)
  • The results suggest a novel mechanism of enzyme inhibition in which the -1 nt at the gyrase-DNA gate exhibit different CL reactivities to produce both irreversible and reversible DNA damage. (nih.gov)
  • DNA polymerase III is a complex, multichain enzyme responsible for most of the replicative synthesis in bacteria. (string-db.org)
  • DNA Gyrase is an enzyme used to unwind double stranded DNA which is essential to DNA Replication. (hatenablog.com)
  • Ellagic acid's mechanism of action against E. coli is via suppression of bacterial reproduction by inhibiting the DNA gyrase enzyme required for bacterial replication. (fxmedicine.com.au)
  • DNA gyrase is an essential bacterial enzyme that catalyses the introduction of negative superhelical turns into closed-circuit double-stranded DNA. (fxmedicine.com.au)
  • Ciprofloxacin inhibits enzyme bacterial DNA gyrase, which nicks double stranded DNA and introduces negative supercoils and then reseals the nicked ends. (rx2go.com)
  • DNA Gyrase - Often referred to simply as gyrase, is an enzyme that relieves strain while double-strand DNA is being unwound by helicase. (saferpills.org)
  • Broken zipper that gets stuck several times before closing: Lagging strand (Okazaki fragments are synthesized discontinuously and later connected by enzyme ligase). (epomedicine.com)
  • Gellert M, O''Dea MH, Mizuuchi K, Nash H. (1976) DNA gyrase: an enzyme that introduces superhelical turns into DNA. (nchu.edu.tw)
  • Here, the two strands are separated and then each strand's complementary DNA sequence is recreated by an enzyme called DNA polymerase . (wikibooks.org)
  • This enzyme makes the complementary strand by finding the correct base through complementary base pairing, and bonding it onto the original strand. (wikibooks.org)
  • In addition to DNA polymerase, the enzyme that synthesizes the new DNA by adding nucleotides matched to the template strand, a number of other proteins are associated with the fork and assist in the initiation and continuation of DNA synthesis. (wikibooks.org)
  • Here, we show that Mycobacterium smegmatis MfpA (MsMfpA) inhibits negative supercoiling by M. smegmatis gyrase (Msgyrase) in the absence of FQs, while in their presence, MsMfpA decreases FQ-induced DNA cleavage, protecting the enzyme from these drugs. (diamond.ac.uk)
  • ATP-dependent breakage, passage and rejoining of double-stranded DNA. (rcsb.org)
  • it inhibits relaxation of supercoiled DNA and promotes breakage of double-stranded DNA. (medscape.com)
  • One of its metabolite directly binds to bacterial DNA, causes loss of its helical structure, and effects strand breakage. (dentalcare.com)
  • Alters structure of bacterial DNA gyrase, thus promoting double-stranded DNA breakage, interfering with synthesis of bacterial protein and blocking bacterial survival. (underthemeso.com)
  • Inhibition of DNA gyrase in susceptible organisms resulting in inhibition of ATP-depending negative supercoiling DNA, inhibition of ATP-dependent relaxation of supercoiled DNA and promotion of double-stranded DNA breakage. (mims.com)
  • Breakage-reunion domain contains catalytic tyrosine, responsible for the cleavage and re-ligation of the DNA double helix and form DNA duplex [ 7 ]. (ijddr.in)
  • Control of topological states of DNA by transient breakage and subsequent rejoining of DNA strands. (thermofisher.com)
  • Direct lesion reversal removes DNA damage without need for excision and de novo DNA synthesis, whereas DNA excision repair that includes pathways such as base excision, nucleotide excision, alternative excision and mismatch repair, proceeds through phosphodiester bond breakage, de novo DNA synthesis and ligation. (asmscience.org)
  • CL-stimulated DNA breakage exhibited a strong preference for guanine preceding the scission site (-1 position). (nih.gov)
  • The specificity of gyrase-mediated DNA breakage promoted by CL was examined using the 5′-end 33P-labelled S fragment from the S. pneumoniae parE gene and compared to that of gemifloxacin, an anti-pneumococcal quinolone whose induction of sequence-specific cleavage has been studied in detail for pneumococcal gyrase and topo IV (31). (nih.gov)
  • Cleavage of TOP and BOTTOM DNA strands by both drugs was markedly enhanced by the inclusion of ATP and required the presence of gyrase: no breakage was seen with CL alone consistent with the known poor reactivity of CL toward duplex DNA (Figure 3, Introduction section). (nih.gov)
  • CL-induced gyrase scission occurred either at single sites or more frequently in pairs on complementary strands showing the characteristic 4-bp stagger expected of double-stranded DNA breakage by gyrase (31). (nih.gov)
  • We assessed ciprofloxacin (CIP)-induced chromosomal DNA breakage in single-cell Escherichia coli by direct visualization of the DNA fragments that diffused from the nucleoid obtained after bacterial lysis in an agarose microgel on a slide. (beds.ac.uk)
  • Ciprofloxacin promotes breakage of double-stranded DNA in susceptible organisms and inhibits DNA gyrase, which is essential in reproduction of bacterial DNA. (medicscientist.com)
  • The Critical Review of Biochemical and Molecular Biology states that DNA gyrase relieves strain while helicase unwinds double-strand DNA. (reference.com)
  • The two unwound single strands of DNA serve as templates for DNA polymerase , which moves with the helicase (together with other proteins) to synthesise a complementary copy of each strand. (wikipedia.org)
  • [8] After DnaB translocates to the apex of each replication fork, the helicase both unwinds the parental DNA and interacts momentarily with primase . (wikipedia.org)
  • In addition, DNA gyrase is needed to relieve the topological stress created by the action of DnaB helicase. (wikipedia.org)
  • HR is initiated by DNA end processing, during which the nucleolytic activity of the Mre11-Rad50- Xrs2/Nbs1 complex (MRX/MRN) and Sae2/CTIP generates short 3′-ssDNA tails that then serve as the substrate for extensive resection by Exo1 exonuclease or Sgs1-Dna2 helicase/endonuclease [4] - [6] . (prolekare.cz)
  • Two more proteins, DNA helicase and DNA primase, then join the complex. (encyclopedia.com)
  • Replication initiation is triggered by the activation of the helicase and primase, and the subsequent recruitment of DNA polymerase. (encyclopedia.com)
  • What does DNA helicase do? (getrevising.co.uk)
  • These 5 proteins are homologs of the helicase in E. coli which unwinds DNA. (sunyorange.edu)
  • Topoisomerase (gyrase) relaxes the supercoiled DNA, and helicase separates the double strand to single strands. (binaryoptionsxpert.com)
  • The double helix is unwound by a helicase and topoisomerase. (wikibooks.org)
  • A type II topoisomerase that negatively supercoils closed circular double-stranded (ds) DNA in an ATP-dependent manner to modulate DNA topology and maintain chromosomes in an underwound state. (rcsb.org)
  • Few gyrases are as efficient as E.coli at forming negative supercoils. (uniprot.org)
  • This process occurs in bacteria, whose single circular DNA is cut by DNA gyrase and the two ends are then twisted around each other to form supercoils. (wikipedia.org)
  • The unique ability of gyrase to introduce negative supercoils into DNA at the expense of ATP hydrolysis is what allows bacterial DNA to have free negative supercoils. (wikipedia.org)
  • The ability of gyrase to relax positive supercoils comes into play during DNA replication and prokaryotic transcription. (wikipedia.org)
  • The ability of gyrase (and topoisomerase IV) to relax positive supercoils allows superhelical tension ahead of the polymerase to be released so that replication can continue. (wikipedia.org)
  • Structurally the complex is formed by 3 pairs of "gates", sequential opening and closing of which results into the direct transfer of DNA segment and introduction of 2 negative supercoils. (wikipedia.org)
  • As the result of a catalytic cycle two ATP molecules are hydrolyzed and two negative supercoils are introduced into the DNA template. (wikipedia.org)
  • eukaryotic topoisomerase I and topoisomerase V). These enzymes are primarily responsible for relaxing positively and/or negatively supercoiled DNA, except for reverse gyrase, which can introduce positive supercoils into DNA. (ebi.ac.uk)
  • NAPs form a functional network that maintains DNA topology by bending, wrapping, bridging and constraining supercoils. (frontiersin.org)
  • These enzymes are responsible for relaxing supercoiled DNA as well as for introducing both negative and positive supercoils [ PMID: 7980433 ]. (ebi.ac.uk)
  • Topoisomerase IV primarily decatenates DNA and relaxes positive supercoils, which is important in bacteria, where the circular chromosome becomes catenated, or linked, during replication [ PMID: 16023670 ]. (ebi.ac.uk)
  • FUNCTION: DNA gyrase negatively supercoils closed circular double- CC stranded DNA in an ATP-dependent manner and also catalyzes the CC interconversion of other topological isomers of double-stranded CC DNA rings, including catenanes and knotted rings (By similarity). (univ-lyon1.fr)
  • DNA gyrase is a type II topoisomerase that catalyzes the introduction of negative supercoils in the genomes of eubacteria. (embl.de)
  • Topoisomerase II (called gyrase in bacteria) primarily introduces negative supercoils into DNA. (embl.de)
  • A bacterial type IIA topoisomerase that is unique in its function of introducing negative supercoils into DNA at the expense of ATP hydrolysis and is also capable of relaxing positive supercoils, an activity shared with topoisomerase IV. (tamu.edu)
  • Together, DNA gyrase and topoisomerase IV generate double-stranded DNA breaks to relieve the strain of the positive DNA supercoils and therefore allow DNA polymerase to replicate the strands of bacteria DNA. (icd10monitor.com)
  • DNA gyrase-A gene not only supercoils the DNA but also enhances the relaxation, DNA cleavage and decatenation activities. (ijddr.in)
  • DNA topoisomerase II (a.k.a DNA gyrase in prokaryotes) removes positive supercoils ahead of advancing replication. (epomedicine.com)
  • DNA gyrase, a type II topoisomerase, introduces negative supercoils into DNA using ATP hydrolysis. (diamond.ac.uk)
  • In 1963, J. Cairns (1) pointed out that the Escherichia coli chromosome is a closed circular double strand DNA molecule. (springer.com)
  • In Escherichia coli , PriA is central to the restart of chromosomal replication when replication fork progression is disrupted and is also involved in homologous recombination and DNA repair. (asm.org)
  • The use of multiple genetic pathways for recombinational DNA repair in N. gonorrhoeae distinguishes it from Escherichia coli , which utilizes the RecF DNA repair pathway only in a mutant recBC sbcBC background ( 22 , 25 ). (asm.org)
  • Recently, high throughput mapping of DNA gyrase sites in the Escherichia coli genome using Topo-Seq approach revealed a long (≈130 bp) and degenerate binding motif that can explain the existence of SGSs. (wikipedia.org)
  • This difference is probably due in part to the sensitivity of gyrase from S. aureus being much lower than that of gyrase from gram-negative species such as Escherichia coli ( 4 ). (asm.org)
  • The Escherichia coli chromosome is a 4.6-Mbp circular double-stranded (ds) DNA duplex, in which the two DNA strands are wrapped around each other ∼420,000 times. (pnas.org)
  • We demonstrate that FQs bind both Escherichia coli and Mycobacterium tuberculosis gyrases in the absence of DNA and that the addition of DNA enhances the drug binding. (embl.de)
  • Studies on DNA repair in Escherichia coli spearheaded formulation of principal strategies to counteract DNA damage and mutagenesis, such as: direct lesion reversal, DNA excision repair, mismatch and recombinational repair and genotoxic stress signalling pathways. (asmscience.org)
  • The three-dimensional structure of the 67K amino-terminal fragment of Escherichia coli DNA topoisomerase I has been determined to 2.2 A resolution. (embl-heidelberg.de)
  • Chow R, Dougherty T, Fraimow H, Bellin E, Miller M. (1988) Association between early inhibition of DNA synthesis and the MICs and MBCs of carboxyquinolone antimicrobial agents for wild-type and mutant [gyrA nfxB(ompF) acrA] Escherichia coli K-12. (nchu.edu.tw)
  • Cullen M, Wyke A, Kuroda R, Fisher L. (1989) Cloning and characterization of a DNA gyrase A gene from Escherichia coli that confers clinical resistance to 4-quinolones. (nchu.edu.tw)
  • Friedman SM, Lu T, Drlica K. (2001) A mutation in the DNA gyrase A gene of Escherichia coli that expands the quinolone-resistance-determining region. (nchu.edu.tw)
  • It was originally discovered in 1968 by Reiji Okazaki, Tsuneko Okazaki, and their colleagues while studying replication of bacteriophage DNA in Escherichia coli . (wikibooks.org)
  • In the heterotetramer, GyrA contains the active site tyrosine that forms a transient covalent intermediate with DNA, while GyrB binds cofactors and catalyzes ATP hydrolysis. (rcsb.org)
  • A sequence-directed DNA curvature was identified in the promoter region of gyrA . (asm.org)
  • The possible implications of the bent DNA region as a regulatory element in the transcription of gyrA are discussed. (asm.org)
  • Gyrase is composed of two A (GyrA) and two B (GyrB) subunits, which are encoded by the gyrA and gyrB genes, respectively. (asm.org)
  • However, E. coli parC resistance mutations are expressed only in the presence of gyrA mutations ( 18 ), and purified E. coli topo IV is less sensitive to quinolones than E. coli gyrase ( 18 ). (asm.org)
  • The two regions correspond to DNA binding by C-terminal domains of GyrA subunits and resemble eukaryotic nucleosome binding motif. (wikipedia.org)
  • The effect of quinolones on the inhibition of DNA synthesis in Staphylococcus aureus was examined by using single resistance mutations in parC or gyrA to distinguish action against gyrase or topoisomerase IV, respectively. (asm.org)
  • At saturating drug concentrations, norfloxacin and a gyrA mutant were used to show that topoisomerase IV-norfloxacin-cleaved DNA complexes are distributed on the S. aureus chromosome at intervals of about 30 kbp. (asm.org)
  • Mutations in gyrA (gyrase) or parC (also called grlA in S. aureus ) (topoisomerase IV) were used to direct the compounds toward one target or the other. (asm.org)
  • drug binding occurs with mutant gyrase ( gyrA ) or topoisomerase IV ( parC ) that fails to cleave DNA ( 9 , 54 ). (asm.org)
  • CL did not induce cleavage by a mutant gyrase (GyrA G79A) identified here in CL-resistant pneumococci. (nih.gov)
  • DNA gyrase is a tetramer with two GyrA and two GyrB subunits, and topoisomerase IV comprises two ParC and two ParE subunits. (beds.ac.uk)
  • After formation of the ternary complex, a DSB is produced by topoisomerase, but bound quinolone inhibits the subsequent ligation of the DNA ends by trapping the topoisomerase on DNA to the GyrA or ParC proteins through a covalent bond of the 5' ends. (beds.ac.uk)
  • Gyrase belongs to the topoisomerase II class of enzymes and is a well-validated target for efficient therapeutic drugs, i. e. the quinolones. (nih.gov)
  • Gyrase is present in prokaryotes and some eukaryotes, but the enzymes are not entirely similar in structure or sequence, and have different affinities for different molecules. (wikipedia.org)
  • Rather, they corrupt the activities of two essential enzymes, DNA gyrase and topoisomerase IV, and induce them to kill cells by generating high levels of double-stranded DNA breaks. (ingentaconnect.com)
  • Unlike Topo IA enzymes, Topo IB enzymes do not require a single-stranded region of DNA or metal ions for their function. (ebi.ac.uk)
  • They belong to the superfamily of DNA breaking-rejoining enzymes, which share the same fold in their C-terminal catalytic domain and the overall reaction mechanism with tyrosine recombinases [ PMID: 21087076 , PMID: 9488644 ]. (ebi.ac.uk)
  • Both enzymes use a double-strand DNA passage mechanism, and it is likely that quinolone biochemistry is similar for both. (asm.org)
  • These enzymes regulate DNA under- and over-winding and remove knots and tangles from the genome. (bioconferencelive.com)
  • During the elongation phase of replication, the enzymes that were assembled at oriC during initiation proceed along each arm (" replichore ") of the chromosome, in opposite directions away from the oriC, replicating the DNA to create two identical copies. (wikipedia.org)
  • Grepafloxacin exerts its antibacterial activity by inhibiting bacterial topoisomerase II (DNA gyrase) and topoisomerase IV, essential enzymes for duplication, transcription, and repair of bacterial DNA. (drugbank.ca)
  • Iron is required for several key processes such as DNA synthesis, mitochondrial electron transport, synthesis of heme, and as a co-factor for many redox enzymes. (embl.de)
  • Large scale production of these enzymes using recombinant DNA technology in our academic laboratory is utilised to avoid dependence on expensive commercially available enzymes. (ejbiotechnology.info)
  • For example, enzymes that cleave only one strand of DNA are defined as type I with a further classification of type I-A subtypes for proteins linked to a 5'-phosphate and type I-B subtypes for proteins attached to a 3'-phosphate during the relaxation of the cleavable DNA. (ejbiotechnology.info)
  • Like fluoroquinolones, gepotidacin acts on the bacterial enzymes gyrase and topoisomerase IV, but details of its interaction with these enzymes are unknown. (vumc.org)
  • I experimented with enzymes that made up DNA at Washington University. (philome.la)
  • As a consequence, cells are equipped with a plethora of DNA repair enzymes to remove the damaged DNA. (asmscience.org)
  • The bactericidal action of temafloxacin results from interference with the activity of the bacterial enzymes DNA gyrase and topoisomerase IV, which are needed for the transcription and replication of bacterial DNA. (drugbank.com)
  • The peptidoglycan layer undergoes cross-linking of the glycan strands by the action of transglycosidases, which serves as an enzymes and the peptide chains which extend from the sugars in the polymers and form cross links, one peptide to another (Kahne et al. (cheapjewelryus.com)
  • Ciprofloxacin acts by inhibiting the enzymes topoisomerase II and topoisomerase IV, which are required for the bacterial DNA transcription, replication, repair and recombination. (assignmentpoint.com)
  • In vitro biochemical experiments have demonstrated that the replicative mitochondrial DNA (mtDNA) polymerase gamma, Polg, is a sensitive target for inhibition by metabolically active forms of NRTIs, nucleotide reverse transcriptase inhibitors (NtRTIs). (frontiersin.org)
  • Which prokaryote RNA polymerase is use for DNA replication? (getrevising.co.uk)
  • In these situations, cells are forced to choose between recombination-mediated "damage avoidance" pathways or a specialized DNA polymerase (pol) to traverse the blocking lesion. (asmscience.org)
  • A sub-unit of the DNA polymerase "proofreads" the new DNA. (wyzant.com)
  • This DNA polymerase also exhibits 3' to 5' exonuclease activity. (string-db.org)
  • Excision endonuclease/Excinuclease (deficient in Xeroderma pigmentosum) removes defective oligonucleotide, DNA polymerase fills the gap and DNA ligase seals the nick in repaired strand. (epomedicine.com)
  • The polymerase chain reaction (PCR) , a common laboratory technique, employs such artificial synthesis in a cyclic manner to amplify a specific target DNA fragment from a pool of DNA. (wikibooks.org)
  • The leading strand is formed along the leading strand template as a polymerase "reads" the template DNA and continuously adds nucleotides to the 3' end of the elongating strand. (wikibooks.org)
  • This polymerase is DNA polymerase III (DNA Pol III) in prokaryotes and presumably Pol ε in eukaryotes. (wikibooks.org)
  • Just as before, DNA Polymerase reads 3'-5' on the original DNA to produce a 5'-3' nascent strand. (wikibooks.org)
  • DNA polymerase III or Pol δ lengthens the primed segments, forming Okazaki fragments . (wikibooks.org)
  • In prokaryotes, DNA polymerase I "reads" the fragments, removes the RNA using its flap endonuclease domain, and replaces the RNA nucleotides with DNA nucleotides (this is necessary because RNA and DNA use slightly different kinds of nucleotides). (wikibooks.org)
  • Next, one DNA polymerase produces the leading strand copy. (wikibooks.org)
  • The ccdB protein binds to and stabilizes the DNA-gyrase complex and a cleavage intermediate and causes double stranded breaks in a replicating genome [ 5 ]. (openwetware.org)
  • Novobiocin binds to DNA gyrase, and blocks adenosine triphosphatase (ATPase) activity. (drugbank.ca)
  • In eukaryotes, the origin recognition complex is a complex of proteins (six in yeast, four of which have homologs in humans) which binds the DNA and the site where replication begins. (sunyorange.edu)
  • RecF binds preferentially to single-stranded, linear DNA. (string-db.org)
  • Trex1 binds to ssDNA in mammalian cells, where it removes mismatched 3'-terminal deoxyribonucleotides at DNA strand breaks. (biosyn.com)
  • The degree of compaction results from the level of DNA-supercoiling and the presence of nucleoid-binding proteins. (frontiersin.org)
  • THF is an essential cofactor in the synthesis of DNA, RNA, and proteins (Figure 7). (dentalcare.com)
  • 4] Failure of DNA to properly separate during these processes results in a bacterium not being able to divide normally or produce functional proteins. (icr.org)
  • In order for DNA replication to continue, single stranded binding proteins are needed to prevent the single strands of DNA from forming secondary structures and to prevent them from re-annealing . (wikipedia.org)
  • If the source of the RM genes are lost, such as through replacement of chromosomal genes from incoming DNA sources, then the subsequent daughter cells of such a cell would have diluted and constantly degrading amount of both RM proteins. (openwetware.org)
  • Squaring up to DNA: pentapeptide repeat proteins and DNA mimicry. (embl.de)
  • Pentapeptide repeat proteins include a number of examples which are thought to function as structural mimics of DNA and act to competitively bind to the type II topoisomerase DNA gyrase, an important antibacterial target. (embl.de)
  • Pentapeptide repeat proteins are therefore of wide interest not only because of their unusual structure, function, and potential as an antibacterial target, but also because knowledge of their mechanism of action may lead to both a greater understanding of the details of DNA gyrase function as well as being a useful template for the design of new DNA gyrase inhibitors. (embl.de)
  • This review summarizes the current state of knowledge regarding pentapeptide repeat proteins, focusing on those that are thought to mimic DNA, and speculates on potential structure-function relationships which may account for their differing specificities. (embl.de)
  • The exposed DNA ends are protected by the Ku70-Ku80 complex (Ku complex) until a repair pathway is chosen and corresponding proteins recruited. (prolekare.cz)
  • In eukaryotes , the DNA molecules that make up the genome are packaged with proteins into chromosomes, each of which contains a single linear DNA molecule. (encyclopedia.com)
  • Replication origins are composed of special sequences of DNA that are recognized by replication initiator proteins, which bind to the origin sequences and then help to assemble other proteins required for DNA replication at these sites. (encyclopedia.com)
  • Click on the protein counts, or double click on taxonomic names to display all proteins containing TOP4c domain in the selected taxonomic class. (embl-heidelberg.de)
  • In E. coli there is one origin on the chromosome (a region of 245 base pairs called OriC ) which is recognized by initiation proteins that open up the double helix. (sunyorange.edu)
  • Helicases typically use ATP to unwind DNA or RNA (thus using ATP and binding to nucleotides are characteristics which they share with ABC proteins, another gene family to which they are related). (sunyorange.edu)
  • Single Strand Binding proteins (SSB - several small proteins) temporarily bind to each side and keep them separate. (wyzant.com)
  • Discontinuous DNA synthesis iv). (scribd.com)
  • synthesis of one of the strands. (scribd.com)
  • Norfloxacin preferentially attacked topoisomerase IV and blocked DNA synthesis slowly, while nalidixic acid targeted gyrase and inhibited replication rapidly. (asm.org)
  • The absence of RecA had little influence on target choice by this assay, indicating that differences in rebound (repair) DNA synthesis were not responsible for the results. (asm.org)
  • Thus, the slow inhibition of DNA synthesis at growth-inhibitory concentrations suggests that a subset of more distantly distributed complexes is physiologically relevant for drug action and is unlikely to be located immediately in front of the DNA replication fork. (asm.org)
  • The complexes block replication fork movement ( 23 ), explaining the well-known ability of the quinolones to inhibit DNA synthesis ( 8 ). (asm.org)
  • In the present work we examined the ability of several quinolones to inhibit DNA synthesis in S. aureus . (asm.org)
  • Even though nalidixic acid is much less potent than norfloxacin, it inhibited DNA synthesis more rapidly. (asm.org)
  • The slower inhibition of DNA synthesis, despite the close spacing of complexes, raises questions about bacterial chromosome structure. (asm.org)
  • Complex formation with gyrase is followed by a rapid, reversible inhibition of DNA synthesis, cessation of growth, and induction of the SOS response. (asm.org)
  • When does DNA & Histone synthesis occur in the cell cycle? (brainscape.com)
  • The separation of the two template strands and the synthesis of new daughter DNA molecules creates a moving "replication fork" (Figure 2), in which, double-stranded DNA is continually unwound and copied. (encyclopedia.com)
  • The DNA molecule has to replicated, then transcribed into Ribonucleic Acid (RNA), and translated by protein synthesis in three very complex processes in order to duplicate itself. (wyzant.com)
  • Fluoroquinolones are a group of broad-spectrum antibiotics that inhibit DNA synthesis. (thewisearticles.com)
  • Improvements in DNA and RNA oligonucleotide synthesis methods enabled the production of long single-stranded DNA (ssDNA) and circular DNA, such as catenanes, chain-like molecules. (biosyn.com)
  • The synthesis of DNA catenanes, chain-like DNA molecules, allows the study of the secondary structure of these molecules. (biosyn.com)
  • Synthesis of new strand in 5'→3′ direction beginning at 3′ end of RNA primer. (epomedicine.com)
  • Cell killing is relatively slow, and the rate of killing seems to correlate with later massive chromosomal DNA fragmentation mediated by a putative protein suicide factor, whose synthesis may be blocked by chloramphenicol. (beds.ac.uk)
  • Unwinding of DNA at the origin, and synthesis of new strands, forms a replication fork . (wikibooks.org)
  • DNA polymerases, isolated from cells, and artificial DNA primers are used to initiate DNA synthesis at known sequences in a template molecule. (wikibooks.org)
  • However, since the DNA is oriented in a manner that does not allow continual synthesis, only small sections can be read at a time. (wikibooks.org)
  • The orientation of the original DNA on the lagging strand prevents continual synthesis. (wikibooks.org)
  • To maintain genome integrity in the face of DNA damage, N. gonorrhoeae has developed various strategies to either reverse, excise, or tolerate DNA damage products via a network of DNA repair mechanisms including base excision repair, nucleotide excision repair, mismatch repair, and recombinational repair ( 18 ). (asm.org)
  • Such replication-dependent DNA breaks may represent an important pathway that contributes to genome rearrangement and/or cytotoxicity. (aacrjournals.org)
  • Mitochondria are eukaryotic organelles that share bacterial features such as a double-membrane structure and a circular multi-copied genome or mitochondrial DNA (mtDNA). (frontiersin.org)
  • Before a cell divides, DNA must be precisely copied, or "replicated," so that each of the two daughter cells can inherit a complete genome, the full set of genes present in the organism. (encyclopedia.com)
  • All living organisms are continually exposed to agents that damage their DNA, which threatens the integrity of their genome. (asmscience.org)
  • Single-stranded DNA (ssDNA) occurs naturally as a transient intermediate during genome maintenance processes. (biosyn.com)
  • Genome maintenance is vital during DNA replication, repair, and recombination. (biosyn.com)
  • As we know Cell division is essential for an organism to grow, but, when a cell divides, it must replicate the DNA (DNA replication take place during S phase) in its genome so that the two daughter cells have the same genetic information as their parent. (wikibooks.org)
  • In a cell, DNA replication begins at specific locations in the genome, called "origins" . (wikibooks.org)
  • DNA gyrase has now become a most promiscuous protein, participating in different molecular pathways such as replication, transcription, transposition and recombination (for review see 3). (springer.com)
  • Neutrophils perpetrate an oxygen-dependent bactericidal attack with the release of numerous highly reactive compounds, including superoxide and H 2 O 2 , resulting in DNA and protein damage in the microbe. (asm.org)
  • Numerous chemicals as well as radiation can lead to covalent protein-DNA adducts, but little is known about the consequences of these adducts in vivo . (aacrjournals.org)
  • One important chemotherapeutic agent that leads to protein-DNA adducts is 5-azacytidine (aza-C), which was first synthesized in 1964 ( 1 ). (aacrjournals.org)
  • Embryonic stem cells and transgenic mice with reduced levels of cytosine MTase were more resistant to aza-dC than the wild-type, suggesting that protein-DNA adduct formation mediates aza-dC cytotoxicity ( 21 ). (aacrjournals.org)
  • In many gram-negative bacteria, resistance to moderate levels of quinolone arises from mutation of the gyrase A protein and resistance to high levels of quinolone arises from mutation of a second gyrase and/or topoisomerase IV site. (asm.org)
  • Streptomyces-produced quinolone and coumarin antibiotics, such as novobiocin, interfere with a protein called gyrase that assists in the normal separation of double-stranded DNA during replication of DNA or transcription of messenger RNA. (icr.org)
  • The E. coli bacterial replication origin, called oriC consists of DNA sequences that are recognised by the DnaA protein, which is highly conserved amongst different bacterial species. (wikipedia.org)
  • DNA sequence elements within ori C that are important for its function include DnaA boxes, a 9-mer repeat with a highly conserved consensus sequence 5' - TTATCCACA - 3', [2] that are recognized by the DnaA protein. (wikipedia.org)
  • DnaA protein plays a crucial role in the initiation of chromosomal DNA replication. (wikipedia.org)
  • The bacterial replication initiator protein is called the dna A protein. (encyclopedia.com)
  • The first step is a change in the conformation of the initiator protein, which causes limited "melting" (that is, the separation of the two strands) of the double-stranded DNA next to the initiator binding site, thus exposing single-stranded regions of the template (Figure 1). (encyclopedia.com)
  • The crystal structure of a large fragment of yeast type II DNA topoisomerase reveals a heart-shaped dimeric protein with a large central hole. (embl-heidelberg.de)
  • Asensio JL, Perez-Lago L, Lazaro JM, Gonzalez C, Serrano-Heras G, Salas M (2011) Novel dimeric structure of phage phi29-encoded protein p56: insights into uracil-DNA glycosylase inhibition. (springer.com)
  • The sulfur-35 never enters the cell but the phosphorus-32 does means our only conclusion for what hold the code for infecting the bacteria lies in the DNA and not the protein. (philome.la)
  • DNA is a code used within cell s to form protein s. (lymphedemapeople.com)
  • Another example is the protein Trex1 which is the major 3'-DNA exonuclease in mammalian cells. (biosyn.com)
  • The protein appears to play a DNA-editing role in DNA replication or gap-filling during DNA repair. (biosyn.com)
  • In most studies of single molecules, DNA or protein molecules are immobilized to a surface and are often mobilized with fluorophores or tethers to allow observations. (biosyn.com)
  • Single-stranded DNA-binding protein (SSB) that supports and prevents reassociation and degradation of single stranded DNA by nucleases. (epomedicine.com)
  • 2005) A fluoroquinolone resistance protein from Mycobacterium tuberculosis that mimics DNA. (nchu.edu.tw)
  • MfpA, a pentapeptide-repeat protein in mycobacteria, protects gyrase from FQs, but its molecular mechanism remains unknown. (diamond.ac.uk)
  • Several studies have shown that the primary target for quinolones in gram-negative bacteria is gyrase, while in the gram-positive bacteria topo IV is the primary target for most quinolones, although it has been reported that sparfloxacin targets gyrase in S. pneumoniae ( 30 ). (asm.org)
  • For some gram-positive bacteria, the situation is reversed: primary resistance occurs through changes in topoisomerase IV while gyrase changes give additional resistance. (asm.org)
  • DNA gyrase is the preferential target in gram-negative bacteria such as E. coli , whereas topoisomerase IV is affected mainly in gram-positive bacteria [ 5 ]. (beds.ac.uk)
  • The fluoroquinolones are potent antibacterial agents that have DNA gyrase and DNA topoisomerase IV as their intracellular targets (reviewed in references 10 , 13 , and 14 ). (asm.org)
  • Fluoroquinolones block topoisomerase type II activity and disrupt the integrity of bacterial DNA. (dentalcare.com)
  • Fluoroquinolones act against Salmonella by inhibiting their DNA replication. (intechopen.com)
  • Unlike fluoroquinolones, which induce double-stranded DNA breaks, gepotidacin induced only single-stranded breaks, even at high concentrations and extended times of exposure. (vumc.org)
  • By preventing the formation of single-stranded DNA, fluoroquinolones inhibit bacterial replication. (thewisearticles.com)
  • Bacterial DNA gyrase is the target of many antibiotics, including fluoroquinolones. (saferpills.org)
  • Fluoroquinolones are extensively used antibiotics that induce DNA double-strand breaks (DSBs) by trapping DNA gyrase and topoisomerase IV on DNA. (beds.ac.uk)
  • The highly effective gyrase-targeted drugs, fluoroquinolones (FQs), interrupt gyrase by stabilizing a DNA-cleavage complex, a transient intermediate in the supercoiling cycle, leading to double-stranded DNA breaks. (diamond.ac.uk)
  • Fluoroquinolones bind and stabilize type IIA topoisomerase-DNA covalent complexes that contain a double-strand break. (nebraska.edu)
  • We discovered that two novel fluoroquinolones having aryl functionality at the N-1 position, UITT-3-217 (217) and UITT-3-227 (227), could inhibit the catalytic activity of human topoisomerase II without stabilizing topoisomerase-DNA complexes, i.e., without poisoning it. (nebraska.edu)
  • If cleaved complexes block DNA replication, as indicated by previous work, such close spacing of topoisomerase-quinolone-DNA complexes should block replication rapidly (replication forks are likely to encounter a cleaved complex within a minute). (asm.org)
  • Depending upon the bacterial species and quinolone employed, either DNA gyrase or topoisomerase IV serves as the primary cytotoxic target of drug action. (ingentaconnect.com)
  • The key event in quinolone action is reversible trapping of gyrase-DNA and topoisomerase IV-DNA complexes. (asm.org)
  • Repair of quinolone-induced DNA damage occurs largely via recombination pathways. (asm.org)
  • Other consequences of quinolone treatment, such as depletion of gyrase and topoisomerase IV activity, are probably less immediate ( 42 ). (asm.org)
  • To provide a framework for considering quinolone lethality, we begin by briefly describing the drug-topoisomerase-DNA complexes. (asm.org)
  • Quinolone resistance is most often associated with mutations at two highly conserved amino acid residues (a serine and an acidic residue) in gyrase and/or topoisomerase IV. (bioconferencelive.com)
  • Molecular basis for the differential quinolone susceptibility of mycobacterial DNA gyrase. (embl.de)
  • Quinolone is specialized in the fact that it can attack bacterial DNA and prevent them from replicating by this process, and are frequently prescribed to the elderly. (hatenablog.com)
  • In the invention Starteroligonukleotide (primer), DNA-probes and testing methods are provided for rapid detection of quinolone Staphylococcus aureus pathogens in clinical specimens described. (google.com)
  • DNA gyrase appears to be the primary quinolone target for gram-negative bacteria. (drugbank.com)
  • Chen CR, Malik M, Snyder M, Drlica K. (1996) DNA gyrase and topoisomerase IV on the bacterial chromosome: quinolone-induced DNA cleavage. (nchu.edu.tw)
  • Burlison JA, Neckers L, Smith AB, Maxwell A, Blagg BS: Novobiocin: redesigning a DNA gyrase inhibitor for selective inhibition of hsp90. (drugbank.ca)
  • It contains two periodic regions in which GC-rich islands are alternated with AT-rich patches by a period close to the period of DNA double helix (≈10.5 bp). (wikipedia.org)
  • In order to prevent and correct of topological problems caused by the DNA double helix, topoisomerase-II catalyzes the relaxation of negatively supercoiled DNA, the knotting and unknotting DNA and the linking complementary rings of single-stranded DNA into double-stranded rings. (tcichemicals.com)
  • The two strands of DNA run in opposite directions, and are wound around each other in a double helix, with the strands held together by hydrogen bonds between paired bases of the nucleotides (A pairs with T, and G pairs with C). (encyclopedia.com)
  • 2. Identify the parts of DNA and how the double helix is put together (bases)? (slideserve.com)
  • Nucleotides are arranged in two long strands that form a spiral called a double helix. (lymphedemapeople.com)
  • The structure of the double helix is somewhat like a ladder, with the base pairs forming the ladder's rungs and the sugar and phosphate molecules forming the vertical sidepieces of the ladder. (lymphedemapeople.com)
  • Each strand of DNA in the double helix can serve as a pattern for duplicating the sequence of bases. (lymphedemapeople.com)
  • Most of the time, DNA is coiled up tightly inside of our chromosomes, but when needed, it unravels its double helix shape, and looks like a twisted rope ladder. (wyzant.com)
  • The backbone of the double helix are alternating molecules of deoxyribose (5 sided sugar) and phosphate groups. (wyzant.com)
  • The original DNA double helix is called the parent strand. (wyzant.com)
  • The new copies automatically re-zip themselves into the double helix. (wyzant.com)
  • Topoisomerase I nicks DNA, relieving torsional tension of the replicating helix. (epomedicine.com)
  • As DNA polymerases can only extend a DNA strand in a 5′ to 3′ direction, different mechanisms are used to copy the antiparallel strands of the double helix. (wikibooks.org)
  • The leading strand template is the template strand of the DNA double helix that is oriented in a 3' to 5' manner. (wikibooks.org)
  • The ccd poison/antidote system of the F plasmid encodes CcdB, a toxin targeting the essential DNA gyrase of E. coli, and CcdA, the unstable antidote that interacts with CcdB to neutralise its toxicity. (nih.gov)
  • When the distribution of norfloxacin-topoisomerase IV-cleaved DNA complexes was measured, they were found at 30-kbp intervals, about three times more often than gyrase complexes on the E. coli chromosome ( 35 ). (asm.org)
  • Why, then, do E . coli and Salmonella exhibit different DNA supercoiling when experiencing the same conditions? (prolekare.cz)
  • Our results establish the basis for the differences in global DNA supercoiling between E . coli and Salmonella , define a signal transduction pathway regulating DNA supercoiling, and identify potential targets for antibacterial agents. (prolekare.cz)
  • John Cairns demonstrated the theta structure of E. coli chromosomal replication in 1963, using an innovative method to visualize DNA replication. (wikipedia.org)
  • Three-dimensional structure of the 67K N-terminal fragment of E. coli DNA topoisomerase I. (embl-heidelberg.de)
  • Exposing the E. coli strain TG1 to CIP starting at a minimum inhibitory concentration (MIC) of 0.012 μg/ml and at increasing doses for 40 min increased the DNA fragmentation progressively. (beds.ac.uk)
  • Four E. coli strains with identified mechanisms of reduced sensitivity to CIP were assessed using this procedure and produced DNA fragmentation levels that were inversely related to MIC dose, except those with very high MIC dose. (beds.ac.uk)
  • According to the catalytic cycle proposed, binding of 2 ATP molecules causes dimerization of ATPase domains of GyrB subunits and capturing of a T-segment of DNA (T- from transferring) in a cavity between GyrB subunits. (wikipedia.org)
  • 22 ), who used antisense DNA inhibition to block the expression of marA , a regulator of an efflux system ( 16 ). (asm.org)
  • The number of superhelical turns introduced into an initially relaxed circular DNA has been calculated to be approximately equal to the number of ATP molecules hydrolyzed by gyrase Therefore, it can be suggested that two ATP molecules are hydrolyzed per cycle of reaction by gyrase, leading to the introduction of a linking difference of -2. (wikipedia.org)
  • During replication, DNA gyrase acts to remove the majority of these strand crossings, but those that remain result in two circular sister molecules that are nontrivially linked. (pnas.org)
  • When the DNA substrate consists of circular DNA molecules, the recombination sites may occur in a single DNA circle or in separate circles. (pnas.org)
  • The entire assembly of molecules involved in DNA replication on each arm is called a " replisome . (wikipedia.org)
  • The genomes of bacterial cells ( prokaryotes ), which lack a nucleus, are typically circular DNA molecules that associate with special structures in the cell membrane. (encyclopedia.com)
  • The DNAs that make up the genomes of bacteria and eukaryotic cells are double-stranded molecules in which each strand is composed of subunits called nucleotides. (encyclopedia.com)
  • DNA replication is said to be semiconservative because each of the two identical daughter molecules contains one of the two parental template strands paired with a new strand. (encyclopedia.com)
  • I then started trying to understand the power source in the cell called ATP which led me to be interested in how DNA is built from smaller molecules. (philome.la)
  • DNA microarrays can be fabricated by robotic spotting of single-stranded DNA PROBE molecules, on to the surface of a microscope slide, such that DNA of known identity is immobilized at precisely defined locations. (thefreedictionary.com)
  • A problem with the use of microarrays is the potential for intra-strand BASE PAIRING in nucleic acid molecules, which could block probe-target interactions and hybrid formation. (thefreedictionary.com)
  • DNA is the king of molecules.An acronym for one of the nucleic acids, standing for deoxyribonucleic acid. (lymphedemapeople.com)
  • 2008). Therefore, the action of antibiotic is actually an interesting way of using ribosomes, DNA, RNA, carbohydrates (peptidoglycan) as signal effector receptors and transducers .If antibiotic compounds play the role of effector molecules in their natural environments, then their mechanism of action could be seen as using their specific targets as signal relays. (cheapjewelryus.com)
  • For many years, DNA gyrase was thought to be responsible both for unlinking replicated daughter chromosomes and for controlling negative superhelical tension in bacterial DNA. (asm.org)
  • Topoisomerase I promotes the relaxation of DNA superhelical tension by introducing a transient single-stranded break in duplex DNA and are vital for the processes of replication, transcription, and recombination [ 2 ]. (xfam.org)
  • Can introduce negative superhelical turns into double-stranded circular DNA. (cathdb.info)
  • Gyrase and topoisomerase IV create transient double-stranded breaks in the genetic material in order to carry out their essential cellular functions. (bioconferencelive.com)
  • The ATPase domain dimerizes the ATP binding and bind with DNA duplex which cause the transient break in DNA duplex and release the DNA [ 8 ]. (ijddr.in)
  • DNA is unwound and nucleotides are matched to make two new strands. (wikibooks.org)
  • A circular prokaryote chromosome is a chromosome in bacteria and archaea , in the form of a molecule of circular DNA. (wikipedia.org)
  • Unlike the linear DNA of most eukaryotes , typical prokaryote chromosomes are circular. (wikipedia.org)
  • Most prokaryote chromosomes contain a circular DNA molecule - there are no free ends to the DNA . (wikipedia.org)
  • Synthetic long single-stranded DNA (ssDNA) as well as circular DNA allow functional studies in vitro and in vivo. (biosyn.com)
  • According to the journal, antibiotics like novobiocin, nalidixic acidand ciprofloxacin target bacterial DNA gyrase when a person is suffering from a disease or an infection. (reference.com)
  • Bacterial DNA gyrase is the target of many antibiotics, including nalidixic acid, novobiocin, and ciprofloxacin. (wikipedia.org)
  • The microorganisms resistant to the ciprofloxacin may be occurs due to the either mutations in the DNA gyrases decreased the permeability of outer membrane or efflux mechanism of drug. (assignmentpoint.com)
  • Negative supercoiling favors strand separation, and DNA replication, transcription, recombination and repair, all of which involve strand separation. (rcsb.org)
  • 2. Pruss GJ, Drlica K. DNA supercoiling and prokaryotic transcription. (prolekare.cz)
  • DNA supercoiling and transcription in bacteria: a two-way street. (prolekare.cz)
  • DNA-supercoiling acts as a general cis regulator of transcription, which can be superimposed upon other types of more specific trans regulatory mechanism. (frontiersin.org)
  • Norfloxacin inhibits DNA topoisomerase (ATP-hydrolyzing), a type II DNA topoisomerase commonly referred to as DNA-gyrase, in susceptible organisms, DNA-gyrase is necessary for bacterial DNA replication and some aspects of transcription, repair, recombination and transposition. (mims.com)
  • Aflatoxins bind to purines, mak-ing base pairing impossible, and they inhibit both DNA replication and RNA transcription. (damasgate.com)
  • These DNA lesions are either cytotoxic, because they block DNA replication and transcription, or mutagenic due to the miscoding nature of the DNA modifications, or both, and are believed to contribute to cell lethality and mutagenesis. (asmscience.org)
  • As a result DNA replication and transcription is inhibited. (drugbank.com)
  • Bacterial DNA information was first used to synthesize an RNA molecule referred to as messenger RNA (m-RNA) through a process known as transcription. (cheapjewelryus.com)
  • It is now clear that topoisomerase IV, rather than gyrase, is responsible for decatenation of interlinked chromosomes. (asm.org)
  • Topoisomerase III requires single-stranded DNA for binding, so it is more efficient at decatenating chromosomes if the DNA circles contain a small gap. (ebi.ac.uk)
  • Cells that do contain chromosomes with DNA ends, or telomeres (most eukaryotes), have acquired elaborate mechanisms to overcome these challenges. (wikipedia.org)
  • A single molecule study has characterized gyrase activity as a function of DNA tension (applied force) and ATP, and proposed a mechanochemical model. (wikipedia.org)
  • Deoxyribonucleic Acid (DNA) is the tiny molecule inside every cell that carries all our genes in a code (genetic code). (wyzant.com)
  • The cell can now undergo cell division and provide each daughter cell with a complete copy of the DNA molecule. (wyzant.com)
  • The second problem relating to DNA gyrase was the observation that coumarins, e.g. novobiocin, and drugs like nalidixic acid inhibit the B and the A subunits of gyrase respectively. (springer.com)
  • DNA helicases utilize the energy from ATP hydrolysis to unwind double-stranded DNA. (cathdb.info)
  • The University of Illinois at Chicago explains that DNA must replicate itself so that during cell division, both daughter cells receive the same genetic in. (reference.com)
  • An important property of DNA is that it can replicate, or make copies of itself. (lymphedemapeople.com)
  • Put simply, without gyrase function, a cell cannot replicate. (fxmedicine.com.au)
  • It shows antibacterial activity by binding with ATPase domain-DNA duplex complex, blocking the DNA replication and cause cell death [ 9 ]. (ijddr.in)
  • Can catalyze the hydrolysis of ATP in the presence of single-stranded DNA, the ATP-dependent uptake of single-stranded DNA by duplex DNA, and the ATP-dependent hybridization of homologous single-stranded DNAs. (string-db.org)
  • After DSB induction, the topoisomerase passes through the DNA duplex, seals the break, and releases DNA. (beds.ac.uk)
  • Some of them unwind duplex DNA with a 3' to 5' polarity (1,3,5,8), other show 5' to 3' polarity (10,11,12,13) or unwind DNA in both directions (14,15). (cathdb.info)
  • As a normal part of their reaction mechanism, gyrase and topoisomerase IV introduce a pair of staggered, single-strand breaks (nicks) into DNA and become covalently bound to the 5′ ends of the cleaved DNA ( 55 , 57 ). (asm.org)
  • Here, we provide a mathematically rigorous characterization of this topological mechanism of DNA unlinking. (pnas.org)
  • Although several models explain the mechanism of FQ action and gyrase-DNA-FQ interaction, the basis for the differential susceptibility of mycobacterial gyrase to various FQs is not understood. (embl.de)
  • The most accurate repair mechanism is based on homologous recombination (HR), in which single strands generated next to the break seek an intact replica which is copied into the broken site. (prolekare.cz)
  • We have developed a method for directly observing the resection process that prepares DNA double-strand breaks for HR. This allows us for the first time to identify just those cells where breaks are being repaired, and so to analyze the repair mechanism with a precision not attainable using current visualization systems. (prolekare.cz)
  • Structure and mechanism of DNA topoisomerase II. (embl-heidelberg.de)
  • Neil Osheroff , PhD, and colleagues have now characterized the mechanism of action of gepotidacin against Staphylococcus aureus gyrase. (vumc.org)
  • These findings indicate replication stalling due to the presence of unprocessed RNA/DNA heteroduplexes, potentially leading to the degradation of collapsed forks or to replication restart by a mechanism involving strand invasion. (nih.gov)
  • The double-stranded structure of DNA provides a simple mechanism for DNA replication. (wikibooks.org)
  • This makes gyrase a good target for antibiotics. (wikipedia.org)
  • These antibiotics prevent unwinding of double-stranded DNA by binding DNA gyrase or DNA topoisomerase. (thewisearticles.com)
  • In addition to DNA repair functions, homologous recombination is also required for pilin antigenic variation and DNA transformation in N. gonorrhoeae . (asm.org)
  • It has been proposed that, after being activated by FtsK, XerC/XerD- dif recombination removes DNA links in a stepwise manner. (pnas.org)
  • Gyrase tends to be the primary target in gram-negative bacteria, while topoisomerase IV is preferentially inhibited by most quinolones in gram-positive organisms ( 28 ). (asm.org)
  • DNA replication is similar in all organisms, suggesting that all life on earth today have only modified the same ancestral mechanisms. (sunyorange.edu)
  • 1) DNA, or deoxyribonucleic acid, is the hereditary material in humans and almost all other organisms. (lymphedemapeople.com)
  • These DNA repair pathways are universal among cellular organisms. (asmscience.org)
  • Gyrase is also trapped on DNA by lethal gene products of certain large, low-copy-number plasmids. (asm.org)
  • The marR gene was cloned from SL1344 DNA using PCR conditions described previously ( 3 ) with 5′-ATGAAAAGCACCAGTGATCTGTTC-3′ and 5′-CCTACGGCAGATT-TTTCTTGAGCAA-3′ as forward and reverse primers, respectively. (asm.org)
  • The compaction of DNA by up to 1000-fold ( Holmes and Cozzarelli, 2000 ) in the bacterial chromosome, or nucleoid, achieves the optimal condition under which its essential functions - replication, segregation and gene expression (reviewed by Dorman, 2013 ) - can be reconciled. (frontiersin.org)
  • Sharma N, Neha K, Yusra A, Chandra NS (2019) Study of Gyrase-A Gene in Mycobacterium tuberculosis Complex and its Clinical Relevance. (ijddr.in)
  • Mycobacterium tuberculosis is causative agent of tuberculosis which possesses only one type II topoisomerase including DNA gyrase-A gene [ 5 ]. (ijddr.in)
  • A collection of tens of thousands of DNA single-strand molecular probes capable of detecting specific genes or measuring gene expression in a sample of tissue. (thefreedictionary.com)
  • Those which bind DNA can function in DNA replication, DNA repair, and even control of gene expression. (sunyorange.edu)
  • The 290-bp S fragment (from the S. pneumoniae parE gene) 33P-labelled at the 5′ end of the TOP or BOTTOM strand was cleaved by S. pneumoniae gyrase in the absence or presence of 200 μM CL or 100 μM gemifloxacin (Gemi) and 1 mM ATP. (nih.gov)
  • DNA cleavage and reunion is performed by a catalytic center located in DNA-gates build by all gyrase subunits. (wikipedia.org)
  • Changes in chromosome dynamics during the early steps that create the single strands have not been analysed owing to lack of tools allowing analysis of this process in individual living cells. (prolekare.cz)
  • We establish by genetic means that CL targets DNA gyrase in the gram-positive bacterium Streptococcus pneumoniae, and promotes gyrase-dependent single- and double-stranded DNA cleavage in vitro. (nih.gov)
  • In bacteria, global DNA supercoiling results from the opposing activities of topoisomerase I, which relaxes DNA, and DNA gyrase, which compacts DNA. (prolekare.cz)
  • Next generation sequencing is an emerging technology with considerable promise for typing of medical important bacteria and yields all of the available DNA information in a single rapid step and provides a high-resolution, accurate and reproducible means that can be used for typing ( 4 , 47 ). (antimicrobe.org)
  • When we look at the infected bacteria it contains radioactive phosphorus-32 which we used to label the DNA. (philome.la)
  • The level of DNA damage was much higher when the bacteria were taken from liquid LB broth than from solid LB agar. (beds.ac.uk)
  • CIP treatment produced a progressively slower rate of DNA damage in bacteria in the stationary phase than in the exponentially growing phase. (beds.ac.uk)
  • If the concentration of the DNA methyltransferase becomes low enough, it will not be able to methylate all of the endonuclease's restriction sites, resulting in DNA cleavage and possibly cell death. (openwetware.org)
  • CL-promoted DNA cleavage mediated by gyrase occurs at specific sites and is stimulated by ATP. (nih.gov)
  • These drug concentrations were chosen so as to achieve comparable cleavage levels of the linear DNA substrate. (nih.gov)
  • Quinolones are known to stabilize DNA cleavage fragments that possess 3′ OH ends and hence co-migrate with chain termination DNA sequencing products (21,31). (nih.gov)
  • In gyrase-containing complexes, the DNA is broken and treatment with ionic detergents releases chromosomal DNA fragments ( 35 ). (asm.org)
  • Measurement of fragment size provides an estimate of the distribution of cleaved complexes on chromosomal DNA ( 35 ). (asm.org)
  • At higher drug concentrations, cell death occurs as double-strand DNA breaks are released from trapped gyrase and/or topoisomerase IV complexes. (asm.org)
  • Crystal structures of human topoisomerase I in covalent and noncovalent complexes with DNA. (ebi.ac.uk)
  • In the present minireview we consider cell death through a two-part "poison" hypothesis in which the quinolones form reversible drug-topoisomerase-DNA complexes that subsequently lead to several types of irreversible (lethal) damage. (asm.org)
  • A binding mode for the anticancer drug camptothecin has been proposed on the basis of chemical and biochemical information combined with the three-dimensional structures of topoisomerase I-DNA complexes [ PUBMED:9488644 ]. (xfam.org)
  • The timing of DNA replication is regulated by controlling the assembly of complexes at replication origins. (encyclopedia.com)
  • The binding of Avelox to DNA gyrase and topoisomerase IV creates complexes termed "topoisomerase poisons" that cleave the bacterial DNA into fragments, resulting in cell death. (icd10monitor.com)
  • On the lagging strand template, primase "reads" the DNA and adds RNA to it in short, separated segments. (wikibooks.org)
  • At a dose of 1 μg/ml of CIP, DNA damage was visualized clearly immediately after processing, and the DNA fragmentation increased progressively with the antibiotic incubation time. (beds.ac.uk)
  • c) a 3′ to 5′ exonuclease primarily active on single-stranded DNA which can selectively remove mismatched terminal nucleotides, thus carrying out a proofreading function. (thefreedictionary.com)
  • DNA nucleotides have a direction, in the same way that an arrow has a head and a tail. (encyclopedia.com)
  • These make a complementary strand because the complementary nucleotides pair with the A with T, G with C on the existing strand. (wyzant.com)
  • To facilitate replication, topoisomerase type II, a bacterial DNA gyrase, must first unwind and separate, and then reassemble the original DNA during the process. (dentalcare.com)
  • 7. Carteau S, Mouscadet JF, Goulaouic H, Subra F, Auclair C. Effect of Topoisomerase Inhibitors on the in Vitro HIV DNA Integration Reaction. (prolekare.cz)
  • Similar to Polg, in vitro work has demonstrated both Pol beta and PrimPol incorporate NtRTIs into nascent DNA. (frontiersin.org)
  • DNA replication can also be performed in vitro (outside a cell). (wikibooks.org)
  • It has consequently become apparent that a replication machinery which has to unwind the two strands would generate a positive swivel in front of the advancing replication fork. (springer.com)
  • These results suggest that replication can switch from theta to RC mode after a replication fork is stalled by an MTase-DNA adduct. (aacrjournals.org)
  • RNase H1 promotes replication fork progression through oppositely transcribed regions of Drosophila mitochondrial DNA. (nih.gov)
  • Moreover, topoisomerase IV is a target of the 4-quinolones, antibacterial agents that had previously been thought to target only gyrase. (asm.org)
  • Quinolones are antibacterial agents that act at the level of DNA by inhibiting DNA Gyrase. (hatenablog.com)
  • Prokaryotic DNA as a zipper with single slider (single origin of replication) and Eukaryotic DNA as a zipper with two sliders (multiple origin of replication). (epomedicine.com)
  • Gyrase is also found in eukaryotic plastids: it has been found in the apicoplast of the malarial parasite Plasmodium falciparum and in chloroplasts of several plants. (wikipedia.org)
  • Eukaryotic DNAs each contain multiple replication origins, spaced at intervals of approximately 100,000 base pairs (100 kilobase pairs, or 100 kb) along the length of the DNA. (encyclopedia.com)
  • CcdB acts on gyrase in a similar way as quinolones do, both compounds induce double-strand breaks in DNA. (nih.gov)
  • Clerocidin selectively modifies the gyrase-DNA gate to induce irreversible and reversible DNA damage. (nih.gov)
  • dna contains all the genetic information required to create an organism of a species. (lymphedemapeople.com)
  • The dna material in an organism provides the information that is passed on to offspring. (lymphedemapeople.com)
  • This method is based on the specific digestion (or cutting) of bacterial DNA into fragments of varying sizes, followed by the separation of these DNA fragments into fingerprints by gel electrophoresis. (antimicrobe.org)
  • These fragments of DNA produced on the lagging strand are called Okazaki fragments. (wikibooks.org)
  • This process yields the negative supercoiling of the DNA. (reference.com)
  • This causes negative supercoiling of the DNA. (saferpills.org)