Amino Acids, Peptides, and ProteinsAmino AcidsAmino Acid SequenceAnhydridesMolecular Sequence DataSequence Homology, Amino AcidProteinsAmino Acid SubstitutionCloning, MolecularAmino Acids, EssentialAmino Acid Transport SystemsSequence AlignmentAmino Acid MotifsBase SequenceEscherichia coliMutationBinding SitesMutagenesis, Site-DirectedDNA, ComplementaryAmino Acids, Aromatic