title: Argyrins, immunosuppressive cyclic peptides from myxobacteria. II. Structure elucidation and stereochemistry.
abstract: The structures of argyrins A-H were elucidated by NMR spectroscopy, chemical degradation and X-ray analysis as cyclic octapeptides. Argyrins A and B, in addition to the common amino acids tryptophan, glycine, dehydroalanine and alanine or alpha-aminobutyric acid, sarcosine, contain 2-(1-aminoethyl)thiazol-4-caboxylic acid and the novel amino acid 4'-methoxytryptophan. In argyrins C and D the latter is replaced by 4'-methoxy 2'-methyltryptophan. According to NMR analysis the solution and crystal conformations of argyrins A and B are identical in CDCl3 and slightly different in acetone-d6. Argyrins A and B are identical with the antibiotics A21459 A and B, whose structures are revised with respect to 4'-methoxytryptophan.
authors.affiliation: GBF, Gesellschaft für Biotechnologische Forschung mbH, Abteilung Naturstoffchemie, Braunschweig, Germany.
authors.forename: Larissa
authors.initials: L
authors.lastname: Vollbrecht
authors.forename: Heinrich
authors.initials: H
authors.lastname: Steinmetz
authors.forename: Gerhard
authors.initials: G
authors.lastname: Hofle
authors.forename: Lukas
authors.initials: L
authors.lastname: Oberer
authors.forename: Grety
authors.initials: G
authors.lastname: Rihs
authors.forename: Günter
authors.initials: G
authors.lastname: Bovermann
authors.forename: Peter
authors.initials: P
authors.lastname: von Matt
mesh_terms: D018360:Crystallography, X-Ray; D007166:Immunosuppressive Agents / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008968:Molecular Conformation; D009231:Myxococcales / Q000378:metabolism; D010456:Peptides, Cyclic / Q000737:chemistry*
chemical_list: C099219:A21459 A; C099220:A21459 B; D007166:Immunosuppressive Agents; D010456:Peptides, Cyclic