BIOSYNTHESIS OF PEPTIDE INHIBITOR MR-387 BY STREPTOMYCES-NEYAGAWAENSIS

Biosynthesis of MR-387 by Streptomyces neyagawaensis SL-387 was studie d by testing the incorporation of radioactive precursors and the detec tion of biosynthetic enzyme. L-Phenylalanine, L-valine, L-proline, and acetic acid were efficiently incorporated into MR-387, but phenylethy lamine and oxalic acid were not. These results suggest that the (2S,3R )-3-amino-2-hydroxy-4-phenylbutanoic acid moiety of MR-387 is synthesi zed from phenylalanine and acetic acid but not directly via the phenyl ethylamine. Synthesis of MR-387 is mediated by a peptide synthetase wi th a novel activity.