title: Polytheonamides A and B, highly cytotoxic, linear polypeptides with unprecedented structural features, from the marine sponge, Theonella swinhoei.
abstract: Polytheonamides A and B are highly cytotoxic polypeptides with 48 amino acid residues isolated from the marine sponge, Theonella swinhoei. The structure of polytheonamide B was determined by spectral and chemical methods, especially extensive 2D NMR experiments, which resulted in the unprecedented polypeptide structure; the N-terminal glycine blocked with a 5,5-dimethyl-2-oxo-hexanoyl group, the presence of eight tert-leucine, three beta-hydroxyvaline, six gamma-N-methylasparagine, two gamma-N-methyl-beta-hydroxyasparagine, and beta,beta-dimethymethionine sulfoxide residues. More significantly, it has the sequence of alternating D- and L-amino acids. Polytheonamide A is an epimer of polytheonamide B differing only in the stereochemistry of the sulfoxide of the 44(th) residue.
authors.affiliation: Laboratory of Aquatic Natural Products Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan.
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Hamada
authors.forename: Shigeki
authors.initials: S
authors.lastname: Matsunaga
authors.forename: Gen
authors.initials: G
authors.lastname: Yano
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Fusetani
mesh_terms: D000596:Amino Acids / Q000032:analysis / Q000737:chemistry*; D000818:Animals; D047908:Intracellular Signaling Peptides and Proteins; D008387:Marine Toxins / Q000737:chemistry; D019906:Nuclear Magnetic Resonance, Biomolecular; D011506:Proteins / Q000737:chemistry*; D013237:Stereoisomerism; D047232:Theonella / Q000737:chemistry*
chemical_list: D000596:Amino Acids; D047908:Intracellular Signaling Peptides and Proteins; D008387:Marine Toxins; D011506:Proteins; C111717:polytheonamide B