Amino AcidsSequence Homology, Amino AcidAmino Acid SequenceAmino Acid SubstitutionCloning, MolecularAmino Acids, EssentialAmino Acid Transport SystemsSequence AlignmentBase SequenceAmino Acid MotifsEscherichia coliMutationBinding SitesMutagenesis, Site-DirectedMolecular Sequence DataDNA, ComplementaryAmino Acids, AromaticSequence Homology, Nucleic AcidAmino Acids, Branched-ChainPeptide FragmentsKineticsRecombinant ProteinsAmino Acids, SulfurProtein ConformationLeucineModels, MolecularStructure-Activity RelationshipProtein Structure, TertiaryDNASubstrate SpecificityPeptidesMolecular WeightProtein BindingBacterial ProteinsRestriction MappingCell LinePhylogenySequence Analysis, DNAProteinsRecombinant Fusion ProteinsGenes, BacterialAlanine