Amino Acyl-tRNA Synthetases: A subclass of enzymes that aminoacylate AMINO ACID-SPECIFIC TRANSFER RNA with their corresponding AMINO ACIDS.Peptide Synthases: Ligases that catalyze the joining of adjacent AMINO ACIDS by the formation of carbon-nitrogen bonds between their carboxylic acid groups and amine groups.Lysine-tRNA Ligase: An enzyme that activates lysine with its specific transfer RNA. EC 6.1.1.6.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.Methionine-tRNA Ligase: An enzyme that activates methionine with its specific transfer RNA. EC 6.1.1.10.Transfer RNA Aminoacylation: The conversion of uncharged TRANSFER RNA to AMINO ACYL TRNA.Isoleucine-tRNA Ligase: An enzyme that activates isoleucine with its specific transfer RNA. EC 6.1.1.5.Leucine-tRNA Ligase: An enzyme that activates leucine with its specific transfer RNA. EC 6.1.1.4.Glutamate-tRNA Ligase: An enzyme that activates glutamic acid with its specific transfer RNA. EC 6.1.1.17.Valine-tRNA Ligase: An enzyme that activates valine with its specific transfer RNA. EC 6.1.1.9Sequence Homology, Amino Acid: The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.Phenylalanine-tRNA Ligase: An enzyme that activates phenylalanine with its specific transfer RNA. EC 6.1.1.20.Serine-tRNA Ligase: An enzyme that activates serine with its specific transfer RNA. EC 6.1.1.11.Aspartate-tRNA Ligase: An enzyme that activates aspartic acid with its specific transfer RNA. EC 6.1.1.12.Arginine-tRNA Ligase: An enzyme that activates arginine with its specific transfer RNA. EC 6.1.1.19.Tyrosine-tRNA Ligase: An enzyme that activates tyrosine with its specific transfer RNA. EC 6.1.1.1.Coenzyme A Ligases: Enzymes that catalyze the formation of acyl-CoA derivatives. EC 6.2.1.Glycine-tRNA Ligase: An enzyme that activates glycine with its specific transfer RNA. EC 6.1.1.14.Histidine-tRNA Ligase: An enzyme that activates histidine with its specific transfer RNA. EC 6.1.1.21.Aminoacylation: A reaction that introduces an aminoacyl group to a molecule. TRANSFER RNA AMINOACYLATION is the first step in GENETIC TRANSLATION.Tryptophan-tRNA Ligase: An enzyme that activates tryptophan with its specific transfer RNA. EC 6.1.1.2.RNA, Transfer: 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.Escherichia coli: 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.Threonine-tRNA Ligase: An enzyme that activates threonine with its specific transfer RNA. EC 6.1.1.3.Molecular Sequence Data: 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.RNA, Transfer, Amino Acyl: 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.Peptide Biosynthesis, Nucleic Acid-Independent: The enzymatic synthesis of PEPTIDES without an RNA template by processes that do not use the ribosomal apparatus (RIBOSOMES).Amino Acid 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.Alanine-tRNA Ligase: An enzyme that activates alanine with its specific transfer RNA. EC 6.1.1.7.Cloning, Molecular: 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.Substrate Specificity: A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.RNA, Transfer, Gln: A transfer RNA which is specific for carrying glutamine to sites on the ribosomes in preparation for protein synthesis.Sequence Alignment: 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.Anticodon: The sequential set of three nucleotides in TRANSFER RNA that interacts with its complement in MESSENGER RNA, the CODON, during translation in the ribosome.Kinetics: The rate dynamics in chemical or physical systems.Genetic Code: 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).Amino Acid Substitution: 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.Binding Sites: The parts of a macromolecule that directly participate in its specific combination with another molecule.Models, Molecular: Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.RNA, Transfer, Pro: A transfer RNA which is specific for carrying proline to sites on the ribosomes in preparation for protein synthesis.Mutation: 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.Acylation: The addition of an organic acid radical into a molecule.Protein Structure, Tertiary: 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.Tyrocidine: 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.Isoleucine: 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.RNA, Transfer, Glu: A transfer RNA which is specific for carrying glutamic acid to sites on the ribosomes in preparation for protein synthesis.Bacterial Proteins: Proteins found in any species of bacterium.Acetate-CoA Ligase: 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.