title: Ohmyungsamycins A and B: cytotoxic and antimicrobial cyclic peptides produced by Streptomyces sp. from a volcanic island.
abstract: Ohmyungsamycins A and B (1 and 2), which are new cyclic peptides, were isolated from a marine bacterial strain belonging to the Streptomyces genus collected from a sand beach on Jeju, a volcanic island in the Republic of Korea. Based on the interpretation of the NMR, UV, and IR spectroscopic and MS data, the planar structures of 1 and 2 were elucidated as cyclic depsipeptides bearing unusual amino acid units, including N-methyl-4-methoxytrytophan, β-hydroxyphenylalanine, and N,N-dimethylvaline. The absolute configurations of the α-carbons of the amino acid residues were determined using the advanced Marfey's method. The configurations of the additional stereogenic centers at the β-carbons of the threonine, N-methylthreonine, and β-hydroxyphenylalanine units were assigned by GITC (2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl isothiocyanate) derivatization and the modified Mosher's method. We have developed a new method utilizing PGME (phenylglycine methyl ester) derivatization coupled with chromatographic analysis to determine the absolute configuration of N,N-dimethylvaline. Our first successful establishment of the absolute configuration of N,N-dimethylvaline using PGME will provide a general and convenient analytical method for determining the absolute configurations of amino acids with fully substituted amine groups. Ohmyungsamycins A and B showed significant inhibitory activities against diverse cancer cells as well as antibacterial effects.
authors.affiliation: Natural Products Research Institute, College of Pharmacy, Seoul National University , 1 Gwanak-ro, Gwanak-gu, Seoul 151-742, Republic of Korea.
authors.forename: Soohyun
authors.initials: S
authors.lastname: Um
authors.forename: Tae Joon
authors.initials: TJ
authors.lastname: Choi
authors.forename: Heegyu
authors.initials: H
authors.lastname: Kim
authors.forename: Byung Yong
authors.initials: BY
authors.lastname: Kim
authors.forename: Seong-Hwan
authors.initials: SH
authors.lastname: Kim
authors.forename: Sang Kook
authors.initials: SK
authors.lastname: Lee
authors.forename: Ki-Bong
authors.initials: KB
authors.lastname: Oh
authors.forename: Jongheon
authors.initials: J
authors.lastname: Shin
authors.forename: Dong-Chan
authors.initials: DC
authors.lastname: Oh
mesh_terms: D000900:Anti-Bacterial Agents / Q000096:biosynthesis / Q000737:chemistry / Q000494:pharmacology*; D000970:Antineoplastic Agents / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects*; D049109:Cell Proliferation / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004354:Drug Screening Assays, Antitumor; D045325:HCT116 Cells; D006801:Humans; D062312:Islands; D008826:Microbial Sensitivity Tests; D008968:Molecular Conformation; D010456:Peptides, Cyclic / Q000096:biosynthesis / Q000737:chemistry / Q000494:pharmacology*; D012987:Soil / Q000737:chemistry; D013302:Streptomyces / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D013329:Structure-Activity Relationship; D014407:Tumor Cells, Cultured; D047630:Depsipeptides
chemical_list: D000900:Anti-Bacterial Agents; D000970:Antineoplastic Agents; D010456:Peptides, Cyclic; D012987:Soil; C000589266:ohmyungsamycin A; D047630:Depsipeptides; C000589267:ohmyungsamycin B