37 抗生物質Longicatenamycinの化学構造

概要

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Longicatenamycin is a new peptide antibiotic which was isolated from Streptomyces diastaticus S-520 and reported to be effective against Gram positive bacteria. This is a mixture of congeners of cyclic hexapeptide with three exchangeable amino acid residues. Constituent amino acids were established to be each one mole of glycine, D-ornithine (D-lysine), D-valine (D-isoleucine), threo-β-hydroxy-L-glutamic acid, L-α-amino isooctanoic acid (L-α-amino isoheptanoic acid, L-α-amino isononanoic acid) and 5-chloro-D-tryptophan, of which the amino acids in parenthesis were the replaceable ones at each position. Free amino group in longicatenamycin was shown to be only δ-amino group of ornithine (ε-amino group in lysine) by means of 2,4-dinitrophenylation and hydrolysis. Although partial hydrolysis of this peptide with 6N HCl revealed only a sequence of Lca (α-amino isoalkanoic acid)-Val (Ile)-Orn (Lys), the selective chemical cleavage by oxidation with N-bromosuccinimide followed by Edman degradation clarified the total structure of longicatenamycin as shown below. cyclo (Lca-Val-Orn-HyGlu-ClTrp-Gly) Lca: L-α-aminoisooctanoic acid and its homologs HyGlu: threo-β-hydroxy-L-glutamic acid ClTrp: 5-chloro-D-tryptophan
天然有機化合物討論会の論文
1974-10-01