A new 3-methyl-4-ethylideneproline-containing peptide from the marine-derived Actinomycete Nocardiopsis lucentensis

Abstract

A new peptide containing 3-methyl-4-ethylideneproline residue was isolated from Norcardiopsis lucentensis CNR-712. The structure of compound was determined by analyses of extensive NMR spectroscopic experiment. Absolute configuration of amino acids including the alkene geometry and two stereogenic centers of 3-methyl-4-ethyldeneproline residue were deduced by ROESY experiment and Advanced Marfey analysis. For the determination of the absolute configuration of modified proline residue, Marfey analysis was performed with four stereoisomers of modified proline residue. Through the comparison of HPLC retention times of L-FDLA derivatives of each, the absolute configuration of modified proline residue was determined to (2S, 3R, E)-3-methyl-4-ethylideneproline.