DOI: 10.1021/acs.jnatprod.6c01093 ISSN: 0163-3864
Piperapeptins A and B, Cyclic Hexapeptides Containing the Rare Amino Acid Piperazic Acid, Produced by a Combined-Culture of Amycolatopsis sp. and Tsukamurella pulmonis
Chengqian Pan, Maki Kurimura, Mai Taniguchi, Takefumi Kuranaga, Yuko Kishida, Hidehiro Uekusa, Aa Haeruman Azam, Kotaro Kiga, Koichi Watashi, Hiroyasu Onaka, Naoya Shinzato, Hideaki KakeyaAbstract
The novel cyclic hexapeptides, piperapeptins A (1) and B (2) with rare N−OH-Leu and piperazic acid moieties, were discovered in the combined-culture broth of Amycolatopsis sp. 26-11 and Tsukamurella pulmonis TP-B0596. The planar structures were elucidated by HR-MS and 1D/2D NMR analyses. The stereochemistry of Ala and Phe was determined using our highly sensitive advanced Marfey’s method. The structures of N-OH-Leu, piperazic acids, and 4-OH-piperazic acids were confirmed by single-crystal X-ray diffraction analysis. Piperapeptins A (1) and B (2) exhibited weak antibacterial activity against Bacillus subtilis, and 1 showed an IC50 value of 14.9 ± 3.9 μM against HeLa S3 cells.