Amino AcidsSequence Homology, Amino AcidAmino Acid SequenceAmino Acid SubstitutionCloning, MolecularAmino Acids, EssentialMolecular Sequence DataAmino Acid Transport SystemsBase SequenceSequence AlignmentEscherichia coliBinding SitesPeptide FragmentsAmino Acid MotifsPeptidesMutationKineticsMutagenesis, Site-DirectedRecombinant ProteinsDNA, ComplementaryModels, MolecularProtein ConformationSequence Homology, Nucleic AcidSynthetic BiologySubstrate SpecificityAmino Acids, AromaticAmino Acids, Branched-ChainDNALeucineProtein BindingGenes, SyntheticAmino Acids, SulfurProtein Structure, TertiaryCell LineMolecular WeightBacterial ProteinsStructure-Activity RelationshipRestriction MappingRecombinant Fusion ProteinsRNA, MessengerElectrophoresis, Polyacrylamide GelProteinsChromatography, High Pressure LiquidPlasmidsSequence Analysis, DNAProtein Structure, SecondaryPhylogenyAlanine