A subclass of enzymes that aminoacylate AMINO ACID-SPECIFIC TRANSFER RNA with their corresponding AMINO ACIDS.

Intermediates in protein biosynthesis. The compounds are formed from amino acids, ATP and transfer RNA, a reaction catalyzed by aminoacyl tRNA synthetase. They are key compounds in the genetic translation process.

The conversion of uncharged TRANSFER RNA to AMINO ACYL TRNA.

An enzyme that activates isoleucine with its specific transfer RNA. EC 6.1.1.5.

An enzyme that activates glycine with its specific transfer RNA. EC 6.1.1.14.

An enzyme that activates alanine with its specific transfer RNA. EC 6.1.1.7.

An enzyme that activates methionine with its specific transfer RNA. EC 6.1.1.10.

An enzyme that activates tyrosine with its specific transfer RNA. EC 6.1.1.1.

The small RNA molecules, 73-80 nucleotides long, that function during translation (TRANSLATION, GENETIC) to align AMINO ACIDS at the RIBOSOMES in a sequence determined by the mRNA (RNA, MESSENGER). There are about 30 different transfer RNAs. Each recognizes a specific CODON set on the mRNA through its own ANTICODON and as aminoacyl tRNAs (RNA, TRANSFER, AMINO ACYL), each carries a specific amino acid to the ribosome to add to the elongating peptide chains.

A reaction that introduces an aminoacyl group to a molecule. TRANSFER RNA AMINOACYLATION is the first step in GENETIC TRANSLATION.

The sequential set of three nucleotides in TRANSFER RNA that interacts with its complement in MESSENGER RNA, the CODON, during translation in the ribosome.

The meaning ascribed to the BASE SEQUENCE with respect to how it is translated into AMINO ACID SEQUENCE. The start, stop, and order of amino acids of a protein is specified by consecutive triplets of nucleotides called codons (CODON).

An enzyme that activates tryptophan with its specific transfer RNA. EC 6.1.1.2.

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.

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.

The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.

The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.

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.

Ligases that catalyze the joining of adjacent AMINO ACIDS by the formation of carbon-nitrogen bonds between their carboxylic acid groups and amine groups.

Enzymes that catalyze the S-adenosyl-L-methionine-dependent methylation of ribonucleotide bases within a transfer RNA molecule. EC 2.1.1.

An enzyme that activates lysine with its specific transfer RNA. EC 6.1.1.6.

The biosynthesis of PEPTIDES and PROTEINS on RIBOSOMES, directed by MESSENGER RNA, via TRANSFER RNA that is charged with standard proteinogenic AMINO ACIDS.

Organic compounds that generally contain an amino (-NH2) and a carboxyl (-COOH) group. Twenty alpha-amino acids are the subunits which are polymerized to form proteins.

An enzyme that activates leucine with its specific transfer RNA. EC 6.1.1.4.

An enzyme that activates glutamic acid with its specific transfer RNA. EC 6.1.1.17.

An enzyme that activates serine with its specific transfer RNA. EC 6.1.1.11.

Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.

The arrangement of two or more amino acid or base sequences from an organism or organisms in such a way as to align areas of the sequences sharing common properties. The degree of relatedness or homology between the sequences is predicted computationally or statistically based on weights assigned to the elements aligned between the sequences. This in turn can serve as a potential indicator of the genetic relatedness between the organisms.

An enzyme that activates valine with its specific transfer RNA. EC 6.1.1.9

An enzyme that activates phenylalanine with its specific transfer RNA. EC 6.1.1.20.

The parts of a macromolecule that directly participate in its specific combination with another molecule.

An enzyme that activates aspartic acid with its specific transfer RNA. EC 6.1.1.12.

An enzyme that activates arginine with its specific transfer RNA. EC 6.1.1.19.

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.

An enzyme that activates histidine with its specific transfer RNA. EC 6.1.1.21.

The addition of an organic acid radical into a molecule.

Enzymes that catalyze the formation of acyl-CoA derivatives. EC 6.2.1.

A transfer RNA which is specific for carrying glutamine to sites on the ribosomes in preparation for protein synthesis.

A group of transfer RNAs which are specific for carrying each one of the 20 amino acids to the ribosome in preparation for protein synthesis.

A transfer RNA which is specific for carrying serine to sites on the ribosomes in preparation for protein synthesis.

An enzyme that activates threonine with its specific transfer RNA. EC 6.1.1.3.

A transfer RNA which is specific for carrying glutamic acid to sites on the ribosomes in preparation for protein synthesis.

S-Acyl coenzyme A. Fatty acid coenzyme A derivatives that are involved in the biosynthesis and oxidation of fatty acids as well as in ceramide formation.

A transfer RNA which is specific for carrying glycine to sites on the ribosomes in preparation for protein synthesis.

A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts.

The spatial arrangement of the atoms of a nucleic acid or polynucleotide that results in its characteristic 3-dimensional shape.

A transfer RNA which is specific for carrying proline to sites on the ribosomes in preparation for protein synthesis.

A transfer RNA which is specific for carrying isoleucine to sites on the ribosomes in preparation for protein synthesis.

A transfer RNA which is specific for carrying tryptophan to sites on the ribosomes in preparation for protein synthesis.

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 transfer RNA which is specific for carrying methionine to sites on the ribosomes. During initiation of protein synthesis, tRNA(f)Met in prokaryotic cells and tRNA(i)Met in eukaryotic cells binds to the start codon (CODON, INITIATOR).

The rate dynamics in chemical or physical systems.

A transfer RNA which is specific for carrying aspartic acid to sites on the ribosomes in preparation for protein synthesis.

A transfer RNA which is specific for carrying alanine to sites on the ribosomes in preparation for protein synthesis.

A transfer RNA which is specific for carrying phenylalanine to sites on the ribosomes in preparation for protein synthesis.

The enzymatic synthesis of PEPTIDES without an RNA template by processes that do not use the ribosomal apparatus (RIBOSOMES).

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.

A transfer RNA which is specific for carrying cysteine to sites on the ribosomes in preparation for protein synthesis.

A transfer RNA which is specific for carrying arginine to sites on the ribosomes in preparation for protein synthesis.

A species of the genus SACCHAROMYCES, family Saccharomycetaceae, order Saccharomycetales, known as "baker's" or "brewer's" yeast. The dried form is used as a dietary supplement.

Ribonucleic acid in bacteria having regulatory and catalytic roles as well as involvement in protein synthesis.

A set of three nucleotides in a protein coding sequence that specifies individual amino acids or a termination signal (CODON, TERMINATOR). Most codons are universal, but some organisms do not produce the transfer RNAs (RNA, TRANSFER) complementary to all codons. These codons are referred to as unassigned codons (CODONS, NONSENSE).

A transfer RNA which is specific for carrying histidine to sites on the ribosomes in preparation for protein synthesis.

Proteins found in any species of bacterium.

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.

An essential branched-chain aliphatic amino acid found in many proteins. It is an isomer of LEUCINE. It is important in hemoglobin synthesis and regulation of blood sugar and energy levels.

The relationships of groups of organisms as reflected by their genetic makeup.

A transfer RNA which is specific for carrying valine to sites on the ribosomes in preparation for protein synthesis.

A species of gram-negative, aerobic, rod-shaped bacteria found in hot springs of neutral to alkaline pH, as well as in hot-water heaters.

The functional hereditary units of BACTERIA.

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 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 class of enzymes that catalyze the formation of a bond between two substrate molecules, coupled with the hydrolysis of a pyrophosphate bond in ATP or a similar energy donor. (Dorland, 28th ed) EC 6.

The process of cumulative change at the level of DNA; RNA; and PROTEINS, over successive generations.

Enzymes from the transferase class that catalyze the transfer of acyl groups from donor to acceptor, forming either esters or amides. (From Enzyme Nomenclature 1992) EC 2.3.

An antibiotic mixture produced by Bacillus brevis which may be separated into three components, tyrocidines A, B, and C. It is the major constituent (40-60 per cent) of tyrothricin, gramicidin accounting for the remaining 10-20 per cent active material. It is a topical antimicrobial agent, that is very toxic parenterally.

An intermediate in the pathway of coenzyme A formation in mammalian liver and some microorganisms.

Adenine nucleotide containing one phosphate group esterified to the sugar moiety in the 2'-, 3'-, or 5'-position.

Genetically engineered MUTAGENESIS at a specific site in the DNA molecule that introduces a base substitution, or an insertion or deletion.

An essential branched-chain amino acid important for hemoglobin formation.

The sequential correspondence of nucleotides in one nucleic acid molecule with those of another nucleic acid molecule. Sequence homology is an indication of the genetic relatedness of different organisms and gene function.

Proteins prepared by recombinant DNA technology.

An enzyme that catalyzes the formation of CoA derivatives from ATP, acetate, and CoA to form AMP, pyrophosphate, and acetyl CoA. It acts also on propionates and acrylates. EC 6.2.1.1.

The region of an enzyme that interacts with its substrate to cause the enzymatic reaction.

The restriction of a characteristic behavior, anatomical structure or physical system, such as immune response; metabolic response, or gene or gene variant to the members of one species. It refers to that property which differentiates one species from another but it is also used for phylogenetic levels higher or lower than the species.

The facilitation of a chemical reaction by material (catalyst) that is not consumed by the reaction.

A branched-chain essential amino acid that has stimulant activity. It promotes muscle growth and tissue repair. It is a precursor in the penicillin biosynthetic pathway.

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.

The sum of the weight of all the atoms in a molecule.

Multicomponent ribonucleoprotein structures found in the CYTOPLASM of all cells, and in MITOCHONDRIA, and PLASTIDS. They function in PROTEIN BIOSYNTHESIS via GENETIC TRANSLATION.

Commonly observed structural components of proteins formed by simple combinations of adjacent secondary structures. A commonly observed structure may be composed of a CONSERVED SEQUENCE which can be represented by a CONSENSUS SEQUENCE.

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.

A family of anaerobic, coccoid to rod-shaped METHANOBACTERIALES. Cell membranes are composed mainly of polyisoprenoid hydrocarbons ether-linked to glycerol. Its organisms are found in anaerobic habitats throughout nature.

A transfer RNA which is specific for carrying asparagine to sites on the ribosomes in preparation for protein synthesis.

The location of the atoms, groups or ions relative to one another in a molecule, as well as the number, type and location of covalent bonds.

Systems of enzymes which function sequentially by catalyzing consecutive reactions linked by common metabolic intermediates. They may involve simply a transfer of water molecules or hydrogen atoms and may be associated with large supramolecular structures such as MITOCHONDRIA or RIBOSOMES.

Ribonucleic acid in fungi having regulatory and catalytic roles as well as involvement in protein synthesis.

A set of genes descended by duplication and variation from some ancestral gene. Such genes may be clustered together on the same chromosome or dispersed on different chromosomes. Examples of multigene families include those that encode the hemoglobins, immunoglobulins, histocompatibility antigens, actins, tubulins, keratins, collagens, heat shock proteins, salivary glue proteins, chorion proteins, cuticle proteins, yolk proteins, and phaseolins, as well as histones, ribosomal RNA, and transfer RNA genes. The latter three are examples of reiterated genes, where hundreds of identical genes are present in a tandem array. (King & Stanfield, A Dictionary of Genetics, 4th ed)

A process that changes the nucleotide sequence of mRNA from that of the DNA template encoding it. Some major classes of RNA editing are as follows: 1, the conversion of cytosine to uracil in mRNA; 2, the addition of variable number of guanines at pre-determined sites; and 3, the addition and deletion of uracils, templated by guide-RNAs (RNA, GUIDE).

Organic, monobasic acids derived from hydrocarbons by the equivalent of oxidation of a methyl group to an alcohol, aldehyde, and then acid. Fatty acids are saturated and unsaturated (FATTY ACIDS, UNSATURATED). (Grant & Hackh's Chemical Dictionary, 5th ed)

The study of crystal structure using X-RAY DIFFRACTION techniques. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)

Enzymes that catalyze the joining of either ammonia or an amide with another molecule, in which the linkage is in the form of a carbon-nitrogen bond. EC 6.3.1.

The biosynthesis of RNA carried out on a template of DNA. The biosynthesis of DNA from an RNA template is called REVERSE TRANSCRIPTION.

An essential aromatic amino acid that is a precursor of MELANIN; DOPAMINE; noradrenalin (NOREPINEPHRINE), and THYROXINE.

A transfer RNA which is specific for carrying threonine to sites on the ribosomes in preparation for protein synthesis.

An essential amino acid. It is often added to animal feed.

Use of restriction endonucleases to analyze and generate a physical map of genomes, genes, or other segments of DNA.

Mutation process that restores the wild-type PHENOTYPE in an organism possessing a mutationally altered GENOTYPE. The second "suppressor" mutation may be on a different gene, on the same gene but located at a distance from the site of the primary mutation, or in extrachromosomal genes (EXTRACHROMOSOMAL INHERITANCE).

A species of GRAM-POSITIVE ENDOSPORE-FORMING BACTERIA in the family BACILLACEAE, found in soil, hot springs, Arctic waters, ocean sediments, and spoiled food products.

A genus of anaerobic coccoid METHANOCOCCACEAE whose organisms are motile by means of polar tufts of flagella. These methanogens are found in salt marshes, marine and estuarine sediments, and the intestinal tract of animals.

A sequence of amino acids in a polypeptide or of nucleotides in DNA or RNA that is similar across multiple species. A known set of conserved sequences is represented by a CONSENSUS SEQUENCE. AMINO ACID MOTIFS are often composed of conserved sequences.

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.

An enzyme that catalyzes the conversion of ATP into a series of (2'-5') linked oligoadenylates and pyrophosphate in the presence of double-stranded RNA. These oligonucleotides activate an endoribonuclease (RNase L) which cleaves single-stranded RNA. Interferons can act as inducers of these reactions. EC 2.7.7.-.

Amino acids that are not synthesized by the human body in amounts sufficient to carry out physiological functions. They are obtained from dietary foodstuffs.

Electrophoresis in which a polyacrylamide gel is used as the diffusion medium.

An enzyme that catalyzes the conversion of ATP, L-glutamate, and NH3 to ADP, orthophosphate, and L-glutamine. It also acts more slowly on 4-methylene-L-glutamate. (From Enzyme Nomenclature, 1992) EC 6.3.1.2.

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.

Short sequences (generally about 10 base pairs) of DNA that are complementary to sequences of messenger RNA and allow reverse transcriptases to start copying the adjacent sequences of mRNA. Primers are used extensively in genetic and molecular biology techniques.

A transfer RNA which is specific for carrying leucine to sites on the ribosomes in preparation for protein synthesis.

A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms.

Ribonucleic acid in archaea having regulatory and catalytic roles as well as involvement in protein synthesis.

A multistage process that includes cloning, physical mapping, subcloning, determination of the DNA SEQUENCE, and information analysis.

A photoactivable URIDINE analog that is used as an affinity label.

Single-stranded complementary DNA synthesized from an RNA template by the action of RNA-dependent DNA polymerase. cDNA (i.e., complementary DNA, not circular DNA, not C-DNA) is used in a variety of molecular cloning experiments as well as serving as a specific hybridization probe.

An enzyme that forms CMP-acylneuraminic acids, which donate the N-acylneuraminic acid residues to the terminal sugar residue of a ganglioside or glycoprotein. EC 2.7.7.43.

The process of cleaving a chemical compound by the addition of a molecule of water.

A test used to determine whether or not complementation (compensation in the form of dominance) will occur in a cell with a given mutant phenotype when another mutant genome, encoding the same mutant phenotype, is introduced into that cell.

A non-essential amino acid that occurs in high levels in its free state in plasma. It is produced from pyruvate by transamination. It is involved in sugar and acid metabolism, increases IMMUNITY, and provides energy for muscle tissue, BRAIN, and the CENTRAL NERVOUS SYSTEM.

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)

Liquid chromatographic techniques which feature high inlet pressures, high sensitivity, and high speed.

The level of protein structure in which regular hydrogen-bond interactions within contiguous stretches of polypeptide chain give rise to alpha helices, beta strands (which align to form beta sheets) or other types of coils. This is the first folding level of protein conformation.

One of the three domains of life (the others being BACTERIA and Eukarya), formerly called Archaebacteria under the taxon Bacteria, but now considered separate and distinct. They are characterized by: (1) the presence of characteristic tRNAs and ribosomal RNAs; (2) the absence of peptidoglycan cell walls; (3) the presence of ether-linked lipids built from branched-chain subunits; and (4) their occurrence in unusual habitats. While archaea resemble bacteria in morphology and genomic organization, they resemble eukarya in their method of genomic replication. The domain contains at least four kingdoms: CRENARCHAEOTA; EURYARCHAEOTA; NANOARCHAEOTA; and KORARCHAEOTA.

Semiautonomous, self-reproducing organelles that occur in the cytoplasm of all cells of most, but not all, eukaryotes. Each mitochondrion is surrounded by a double limiting membrane. The inner membrane is highly invaginated, and its projections are called cristae. Mitochondria are the sites of the reactions of oxidative phosphorylation, which result in the formation of ATP. They contain distinctive RIBOSOMES, transfer RNAs (RNA, TRANSFER); AMINO ACYL T RNA SYNTHETASES; and elongation and termination factors. Mitochondria depend upon genes within the nucleus of the cells in which they reside for many essential messenger RNAs (RNA, MESSENGER). Mitochondria are believed to have arisen from aerobic bacteria that established a symbiotic relationship with primitive protoeukaryotes. (King & Stansfield, A Dictionary of Genetics, 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.

Members of the class of compounds composed of AMINO ACIDS joined together by peptide bonds between adjacent amino acids into linear, branched or cyclical structures. OLIGOPEPTIDES are composed of approximately 2-12 amino acids. Polypeptides are composed of approximately 13 or more amino acids. PROTEINS are linear polypeptides that are normally synthesized on RIBOSOMES.

A species of gram-positive bacteria that is a common soil and water saprophyte.

A transfer RNA which is specific for carrying tyrosine to sites on the ribosomes in preparation for protein synthesis.

A non-essential amino acid present abundantly throughout the body and is involved in many metabolic processes. It is synthesized from GLUTAMIC ACID and AMMONIA. It is the principal carrier of NITROGEN in the body and is an important energy source for many cells.

A sequence of successive nucleotide triplets that are read as CODONS specifying AMINO ACIDS and begin with an INITIATOR CODON and end with a stop codon (CODON, TERMINATOR).

The functional hereditary units of FUNGI.

A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.

Inorganic salts of phosphoric acid that contain two phosphate groups.

Cellular proteins and protein complexes that transport amino acids across biological membranes.

A general term for single-celled rounded fungi that reproduce by budding. Brewers' and bakers' yeasts are SACCHAROMYCES CEREVISIAE; therapeutic dried yeast is YEAST, DRIED.

RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.

Proteins obtained from ESCHERICHIA COLI.

A protein found in bacteria and eukaryotic mitochondria which delivers aminoacyl-tRNA's to the A site of the ribosome. The aminoacyl-tRNA is first bound to a complex of elongation factor Tu containing a molecule of bound GTP. The resulting complex is then bound to the 70S initiation complex. Simultaneously the GTP is hydrolyzed and a Tu-GDP complex is released from the 70S ribosome. The Tu-GTP complex is regenerated from the Tu-GDP complex by the Ts elongation factor and GTP.

Large enzyme complexes composed of a number of component enzymes that are found in STREPTOMYCES which biosynthesize MACROLIDES and other polyketides.

A genus of EUKARYOTES, in the phylum EUGLENIDA, found mostly in stagnant water. Characteristics include a pellicle usually marked by spiral or longitudinal striations.

Chromatography on thin layers of adsorbents rather than in columns. The adsorbent can be alumina, silica gel, silicates, charcoals, or cellulose. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)

One of the three domains of life (the others being Eukarya and ARCHAEA), also called Eubacteria. They are unicellular prokaryotic microorganisms which generally possess rigid cell walls, multiply by cell division, and exhibit three principal forms: round or coccal, rodlike or bacillary, and spiral or spirochetal. Bacteria can be classified by their response to OXYGEN: aerobic, anaerobic, or facultatively anaerobic; by the mode by which they obtain their energy: chemotrophy (via chemical reaction) or PHOTOTROPHY (via light reaction); for chemotrophs by their source of chemical energy: CHEMOLITHOTROPHY (from inorganic compounds) or chemoorganotrophy (from organic compounds); and by their source for CARBON; NITROGEN; etc.; HETEROTROPHY (from organic sources) or AUTOTROPHY (from CARBON DIOXIDE). They can also be classified by whether or not they stain (based on the structure of their CELL WALLS) with CRYSTAL VIOLET dye: gram-negative or gram-positive.

Process of generating a genetic MUTATION. It may occur spontaneously or be induced by MUTAGENS.

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.

A species of STIGMATELLA usually isolated from rotting wood. (From Bergey's Manual of Determinative Bacteriology, 9th ed)

Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.

A sulfur-containing essential L-amino acid that is important in many body functions.

Genes that have a suppressor allele or suppressor mutation (SUPPRESSION, GENETIC) which cancels the effect of a previous mutation, enabling the wild-type phenotype to be maintained or partially restored. For example, amber suppressors cancel the effect of an AMBER NONSENSE MUTATION.

A process of GENETIC TRANSLATION, when an amino acid is transferred from its cognate TRANSFER RNA to the lengthening chain of PEPTIDES.

An essential amino acid that is necessary for normal growth in infants and for NITROGEN balance in adults. It is a precursor of INDOLE ALKALOIDS in plants. It is a precursor of SEROTONIN (hence its use as an antidepressant and sleep aid). It can be a precursor to NIACIN, albeit inefficiently, in mammals.

Post-transcriptional biological modification of messenger, transfer, or ribosomal RNAs or their precursors. It includes cleavage, methylation, thiolation, isopentenylation, pseudouridine formation, conformational changes, and association with ribosomal protein.

Deoxyribonucleic acid that makes up the genetic material of bacteria.

Enzymes that catalyze the transfer of nitrogenous groups, primarily amino groups, from a donor, generally an amino acid, to an acceptor, usually a 2-oxoacid. EC 2.6.

Proteins found in any species of archaeon.

An analytical method used in determining the identity of a chemical based on its mass using mass analyzers/mass spectrometers.

The ginseng plant family of the order Apiales, subclass Rosidae, class Magnoliopsida. Leaves are generally alternate, large, and compound. Flowers are five-parted and arranged in compound flat-topped umbels. The fruit is a berry or (rarely) a drupe (a one-seeded fruit). It is well known for plant preparations used as adaptogens (immune support and anti-fatigue).

Cells of the higher organisms, containing a true nucleus bounded by a nuclear membrane.

Spectroscopic method of measuring the magnetic moment of elementary particles such as atomic nuclei, protons or electrons. It is employed in clinical applications such as NMR Tomography (MAGNETIC RESONANCE IMAGING).

A family of enzymes that catalyze the endonucleolytic cleavage of RNA. It includes EC 3.1.26.-, EC 3.1.27.-, EC 3.1.30.-, and EC 3.1.31.-.

A non-essential amino acid. It is found primarily in gelatin and silk fibroin and used therapeutically as a nutrient. It is also a fast inhibitory neurotransmitter.

Established cell cultures that have the potential to propagate indefinitely.

Proteins obtained from the species SACCHAROMYCES CEREVISIAE. The function of specific proteins from this organism are the subject of intense scientific interest and have been used to derive basic understanding of the functioning similar proteins in higher eukaryotes.

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).

Chromatography on non-ionic gels without regard to the mechanism of solute discrimination.

A metallic element that has the atomic symbol Mg, atomic number 12, and atomic weight 24.31. It is important for the activity of many enzymes, especially those involved in OXIDATIVE PHOSPHORYLATION.

A thiol-containing non-essential amino acid that is oxidized to form CYSTINE.

The production of PEPTIDES or PROTEINS by the constituents of a living organism. The biosynthesis of proteins on RIBOSOMES following an RNA template is termed translation (TRANSLATION, GENETIC). There are other, non-ribosomal peptide biosynthesis (PEPTIDE BIOSYNTHESIS, NUCLEIC ACID-INDEPENDENT) mechanisms carried out by PEPTIDE SYNTHASES and PEPTIDYLTRANSFERASES. Further modifications of peptide chains yield functional peptide and protein molecules.

Techniques used to separate mixtures of substances based on differences in the relative affinities of the substances for mobile and stationary phases. A mobile phase (fluid or gas) passes through a column containing a stationary phase of porous solid or liquid coated on a solid support. Usage is both analytical for small amounts and preparative for bulk amounts.

A multistage process that includes the determination of a sequence (protein, carbohydrate, etc.), its fragmentation and analysis, and the interpretation of the resulting sequence information.

Recombinant proteins produced by the GENETIC TRANSLATION of fused genes formed by the combination of NUCLEIC ACID REGULATORY SEQUENCES of one or more genes with the protein coding sequences of one or more genes.

The facilitation of biochemical reactions with the aid of naturally occurring catalysts such as ENZYMES.

A modified nucleoside which is present in the first position of the anticodon of tRNA-tyrosine, tRNA-histidine, tRNA-asparagine and tRNA-aspartic acid of many organisms. It is believed to play a role in the regulatory function of tRNA. Nucleoside Q can be further modified to nucleoside Q*, which has a mannose or galactose moiety linked to position 4 of its cyclopentenediol moiety.

A genus of BACILLACEAE that are spore-forming, rod-shaped cells. Most species are saprophytic soil forms with only a few species being pathogenic.

The functional genetic units of ARCHAEA.

A basic science concerned with the composition, structure, and properties of matter; and the reactions that occur between substances and the associated energy exchange.

A non-essential amino acid occurring in natural form as the L-isomer. It is synthesized from GLYCINE or THREONINE. It is involved in the biosynthesis of PURINES; PYRIMIDINES; and other amino acids.

Enzymes that catalyze the synthesis of FATTY ACIDS from acetyl-CoA and malonyl-CoA derivatives.

The composition, conformation, and properties of atoms and molecules, and their reaction and interaction processes.

A fractionated cell extract that maintains a biological function. A subcellular fraction isolated by ultracentrifugation or other separation techniques must first be isolated so that a process can be studied free from all of the complex side reactions that occur in a cell. The cell-free system is therefore widely used in cell biology. (From Alberts et al., Molecular Biology of the Cell, 2d ed, p166)

Multicellular, eukaryotic life forms of kingdom Plantae (sensu lato), comprising the VIRIDIPLANTAE; RHODOPHYTA; and GLAUCOPHYTA; all of which acquired chloroplasts by direct endosymbiosis of CYANOBACTERIA. They are characterized by a mainly photosynthetic mode of nutrition; essentially unlimited growth at localized regions of cell divisions (MERISTEMS); cellulose within cells providing rigidity; the absence of organs of locomotion; absence of nervous and sensory systems; and an alternation of haploid and diploid generations.

Cells lacking a nuclear membrane so that the nuclear material is either scattered in the cytoplasm or collected in a nucleoid region.

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).

An enzyme that catalyzes the formation of carbamoyl phosphate from ATP, carbon dioxide, and glutamine. This enzyme is important in the de novo biosynthesis of pyrimidines. EC 6.3.5.5.

The phenomenon whereby compounds whose molecules have the same number and kind of atoms and the same atomic arrangement, but differ in their spatial relationships. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)

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.

An essential amino acid occurring naturally in the L-form, which is the active form. It is found in eggs, milk, gelatin, and other proteins.

Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.

A group of ribonucleotides (up to 12) in which the phosphate residues of each ribonucleotide act as bridges in forming diester linkages between the ribose moieties.

Transferases are enzymes transferring a group, for example, the methyl group or a glycosyl group, from one compound (generally regarded as donor) to another compound (generally regarded as acceptor). The classification is based on the scheme "donor:acceptor group transferase". (Enzyme Nomenclature, 1992) EC 2.