• For example, DNA gyrase, a type II topoisomerase observed in E. coli and most other prokaryotes, introduces negative supercoils and decreases the linking number by 2. (wikipedia.org)
  • Gyrase is also able to remove knots from the bacterial chromosome. (wikipedia.org)
  • Along with gyrase, most prokaryotes also contain a second type IIA topoisomerase, termed topoisomerase IV. (wikipedia.org)
  • Gyrase and topoisomerase IV differ by their C-terminal domains, which is believed to dictate substrate specificity and functionality for these two enzymes. (wikipedia.org)
  • Footprinting indicates that gyrase, which forms a 140-base-pair footprint and wraps DNA, introduces negative supercoils, while topoisomerase IV, which forms a 28-base-pair footprint, does not wrap DNA. (wikipedia.org)
  • Type IIA topoisomerases include the enzymes DNA gyrase, eukaryotic topoisomerase II (topo II), and bacterial topoisomerase IV (topo IV). (wikipedia.org)
  • Type IIA topoisomerases consist of several key motifs: an N-terminal GHKL ATPase domain (for gyrase, Hsp, kinase and MutL), a Toprim domain (a Rossmann fold subclass), which exists in both type II topoisomerases, type IA topoisomerases, and bacterial primase (DnaG), a central DNA-binding core (which structurally forms a heart-shaped structure), and a variable C-terminal domain. (wikipedia.org)
  • The structures of the N-terminal ATPase domain of gyrase and yeast topoisomerase II have been solved in complex with AMPPNP (an ATP analogue), showing that two ATPase domains dimerize to form a closed conformation. (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. (embl.de)
  • Like other fluoroquinolone anti-infectives, ciprofloxacin inhibits DNA synthesis in susceptible organisms via inhibition of the enzymatic activities of 2 members of the DNA topoisomerase class of enzymes, DNA gyrase and topoisomerase IV. (antiinfectivemeds.com)
  • DNA gyrase and topoisomerase IV have distinct essential roles in bacterial DNA replication. (antiinfectivemeds.com)
  • DNA gyrase is a tetramer composed of 2 GyrA and 2 GyrB subunits. (antiinfectivemeds.com)
  • DNA gyrase introduces negative superhelical twists in DNA, an activity important for initiation of DNA replication. (antiinfectivemeds.com)
  • DNA gyrase also facilitates DNA replication by removing positive super helical twists. (antiinfectivemeds.com)
  • Although all fluoroquinolones generally are active against both DNA gyrase and topoisomerase IV, the drugs differ in their relative activities against these enzymes. (antiinfectivemeds.com)
  • The mechanism by which ciprofloxacin's inhibition of DNA gyrase or topoisomerase IV results in death in susceptible organisms has not been fully determined. (antiinfectivemeds.com)
  • DNA gyrase is a class of Type II Topoisomerases that plays an important role in bacterial viability. (biomedicineonline.org)
  • The study focuses on DNA gyrase as a target and shows insights into future drug development. (biomedicineonline.org)
  • The research focuses on the discovery of novel plant-based therapeutic compounds to target DNA gyrase B activity. (biomedicineonline.org)
  • The study employs DNA gyrase as its target and provides information on potential therapeutic targets. (biomedicineonline.org)
  • The goal of the study is to identify innovative plant-based medicinal molecules that specifically target DNA gyrase B activity. (biomedicineonline.org)
  • Cozzarelli, N.R. DNA gyrase and the supercoiling of DNA. (biomedicineonline.org)
  • Type II topoisomerases are topoisomerases that cut both strands of the DNA helix simultaneously in order to manage DNA tangles and supercoils. (wikipedia.org)
  • Eukaryotic type II topoisomerases are homodimers (A2), while prokaryotic type II topoisomerases are heterotetramers (A2B2). (wikipedia.org)
  • Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. (lookformedical.com)
  • Type IIA topoisomerases are essential in the separation of entangled daughter strands during replication. (wikipedia.org)
  • The double helix, made up of a pair of DNA strands, has bases in its core that are joined by hydrogen bonds to form base pairs: adenine always paired with thymine and guanine always paired with cytosine. (rainis.pics)
  • Two of these paired strands make up the DNA molecule, which then twists into a helix. (rainis.pics)
  • Nucleic acids, DNA and RNA, can be considered as the information molecules of the cell. (rainis.pics)
  • In this section, we examine the structures of DNA and RNA and how these structures relate to the functions of these molecules. (rainis.pics)
  • This function is believed to be performed by topoisomerase II in eukaryotes and by topoisomerase IV in prokaryotes. (wikipedia.org)
  • This entry represents the C-terminal region of DNA topoisomerase I enzymes from eukaryotes (type IB enzymes). (embl.de)
  • 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. (embl.de)
  • 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. (embl.de)
  • An enzyme capable of hydrolyzing highly polymerized DNA by splitting phosphodiester linkages, preferentially adjacent to a pyrimidine nucleotide. (lookformedical.com)
  • The enzyme has a preference for double-stranded DNA. (lookformedical.com)
  • In this study, the activity of medicinal compounds to inhibit DNA gyrB is explored. (biomedicineonline.org)
  • Phytochemical screening was performed to study the medication options that could inhibit DNA gyrB. (biomedicineonline.org)
  • It will be simpler to do a follow-up study on discovering bioactive compounds and evaluating their effectiveness in inhibiting DNA gyrB with the help of this preliminary data from the analytical procedures. (biomedicineonline.org)
  • Staphylococcus aureus will be stopped by DNA gyrB inhibition. (biomedicineonline.org)
  • Type IIB topoisomerases are structurally and biochemically distinct, and comprise a single family member, topoisomerase VI (topo VI). (wikipedia.org)
  • Several models to explain this phenomenon have been proposed, including two models that rely on the ability of type IIA topoisomerases to recognize bent DNA duplexes. (wikipedia.org)
  • Unlike type IIA topoisomerases, type IIB topoisomerases cannot simplify DNA topology (see below), but they share several structural features with type IIA topoisomerases. (wikipedia.org)
  • In addition, type IIA topoisomerases are able to simplify DNA topology, while type IIB topoisomerases do not. (wikipedia.org)
  • Type II topoisomerases increase or decrease the linking number of a DNA loop by 2 units, and it promotes chromosome disentanglement. (wikipedia.org)
  • Topoisomerases are ubiquitous enzymes, found in all living organisms. (wikipedia.org)
  • Some organisms have two isoforms of topoisomerase II: alpha and beta. (wikipedia.org)
  • Tse, Y.C., Wang, J.C. E. coli and M. luteus DNA topoisomerase I can catalyze catenation or decatenation of double-stranded DNA rings. (biomedicineonline.org)
  • Biochemistry, electron microscopy, and recent structures of topoisomerase II bound to DNA reveal that type IIA topoisomerases bind at the apices of DNA, supporting this model. (wikipedia.org)
  • Today, every biology student knows about the double helix structure of DNA and how G pairs with C and A pairs with T. (rainis.pics)
  • In the more common B form, the DNA helix has a repeat of 10.5 base pairs per turn, with the sugar and phosphate forming the covalent phosphodiester "backbone" of the molecule, and the bases adenine, guanine, cytosine and thymine line up in the middle, where the base pairs we know today are, which look like the rungs of a ladder. (rainis.pics)
  • 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). (lookformedical.com)
  • DNA sequences which are recognized (directly or indirectly) and bound by a DNA-dependent RNA polymerase during the initiation of transcription. (lookformedical.com)
  • Unlike Topo IA enzymes, Topo IB enzymes do not require a single-stranded region of DNA or metal ions for their function. (embl.de)
  • The complementary structure immediately suggested to Watson and Crick how DNA could (and does) replicate, and further explains how information from DNA is transferred to RNA for protein synthesis. (rainis.pics)
  • A cytotoxic polypeptide quinoxaline antibiotic isolated from Streptomyces echinatus that binds to DNA and inhibits RNA synthesis. (lookformedical.com)
  • Prokaryotes have the ATPase domain and the Toprim fold on one polypeptide (Pfam PF00204), while the DNA cleavage core and the CTD lies on a second polypeptide (Pfam PF00521). (wikipedia.org)
  • DNA cleavage is inhibited where the ligand binds to DNA. (lookformedical.com)
  • This catalyzes endonucleolytic cleavage of DNA yielding 5'-phosphodi- and oligonucleotide end-products. (lookformedical.com)
  • We start with DNA, the genetic information in every cell that is copied and passed from generation to generation. (rainis.pics)
  • DNA was discovered by Friedrich Miescher in 1869 and identified as genetic material in experiments conducted by Oswald Avery, Colin MacLeod, and Maclyn McCarty in the 1940s. (rainis.pics)
  • They use the hydrolysis of ATP, unlike Type I topoisomerase. (wikipedia.org)
  • Type IIA topoisomerases have the special ability to relax DNA to a state below that of thermodynamic equilibrium, a feature unlike type IA, IB, and IIB topoisomerases. (wikipedia.org)
  • There are two subclasses of type II topoisomerases, type IIA and IIB. (wikipedia.org)
  • Type IIB topoisomerases are found in archaea and some higher plants. (wikipedia.org)
  • Type IIA topoisomerases form double-stranded breaks with four-base pair overhangs, while type IIB topoisomerases form double-stranded breaks with two base overhangs. (wikipedia.org)
  • Topoisomerase IV, another type II DNA topoisomerase, is composed of 2 ParC and 2 ParE subunits. (antiinfectivemeds.com)
  • Singh, S.B. Discovery and development of kibdelomycin, a new class of broad-spectrum antibiotics targeting the clinically proven bacterial type II topoisomerase. (biomedicineonline.org)
  • The two classes of topoisomerases possess a similar strand passage mechanism and domain structure (see below), however they also have several important differences. (wikipedia.org)
  • A strand of DNA is a polymer of nucleoside monophosphates linked by phosphodiester bonds. (rainis.pics)
  • by James Watson and Francis Crick to form a model of DNA with which we are familiar today. (rainis.pics)
  • The term nucleotide refers to the building blocks of DNA (deoxyribonucleoside triphosphate, dNTP) and RNA (ribonucleoside triphosphate, NTP). (rainis.pics)
  • Both Pfam signatures are found in the single-chain eukayotic topoisomerase. (wikipedia.org)
  • Nucleotides that contain deoxyribose are called deoxyribonucleotides and are the forms found in DNA. (rainis.pics)
  • In animals, topoisomerase II is a chemotherapy target. (wikipedia.org)
  • In cancers, the topoisomerase IIα is highly expressed in proliferating cells. (wikipedia.org)
  • In this process, these enzymes change the linking number of circular DNA by ±2. (wikipedia.org)
  • This region covers both the catalytic core and the DNA-binding domains. (embl.de)
  • The race to unravel the structure of DNA was one of the greatest scientific stories of the 20th century. (rainis.pics)