Jahnellamides, α‑Keto-β-Methionine-Containing Peptides from the Terrestrial Myxobacterium <i>Jahnella</i> sp.: Structure and Biosynthesis

Abstract

Two new cyclic peptides, termed jahnellamides A and B, were isolated from the myxobacterium <i>Jahnella</i> sp. Their structures were solved by NMR, ESIMS, and chemical derivatizations. Jahnellamides are a new class of α-ketoamide-containing peptides comprised of nonproteinogenic amino acids, including α-keto-β-methionine and 4-hydroxyglutamic acid. Moreover, <i>in silico</i> analysis of the genome sequence along with feeding experiments allowed us to identify and annotate a candidate nonribosomal peptide synthetase biosynthetic gene cluster containing a polyketide synthase module involved in the formation of the α-ketoamide moiety