Formation of the nonproteinogenic amino acid 2S,3R-capreomycidine by VioD from the viomycin biosynthesis pathway

The tuberactinomycin peptide antibiotics possess several nonproteinogenic amino acids, including the signature capreomycidine residue arising from the oxidative cyclization of the L-arginine side chain. The vioD gene from the recently cloned viomycin biosynthesis gene cluster was expressed in E. coli, and the corresponding protein shown to catalyze the pyridoxal phosphate dependent conversion of 3S-hydroxy-L-arginine to 2S,3R-capreomycidine. VioD is the first example of a PLP-dependent enzyme that promotes an intramolecular β-replacement reaction.