Streptocidins A-D, novel cyclic decapeptide antibiotics produced by Streptomyces sp. Tü 6071. II. Structure elucidation

• Published in: Journal of antibiotics Vol. 54; no. 5; p. 434
• Main Authors: Höltzel, A, Jack, R W, Nicholson, G J, Jung, G, Gebhardt, K, Fiedler, H P, Süssmuth, R D
• Format: Journal Article
• Language: English
• Published: Japan 25-05-2001
• Subjects: Amino Acid Sequence; Amino Acids - analysis; Anti-Bacterial Agents - chemistry; Gas Chromatography-Mass Spectrometry; Magnetic Resonance Spectroscopy; Peptides, Cyclic - chemistry; Peptides, Cyclic - isolation & purification; Peptides, Cyclic - pharmacology; Protein Structure, Secondary; Sequence Analysis, Protein; Spectrometry, Mass, Electrospray Ionization; Streptomyces - chemistry; Streptomyces - metabolism
• ISSN: 0021-8820
• DOI: 10.7164/antibiotics.54.434

The structures of the new antibiotics streptocidins A approximately D were elucidated as cyclic decapeptides cyclo[L-Val1-L-Orn2-L-Leu3-D-Phe4-L-Pro5-L-Leu6-X7-L-Asn8-L-Gln9-X10] with X7=D-Trp (A, B, C) or D-Phe (D) and X10=L-Tyr (A), L-Trp (B, D), or D-Trp (C). The amino acid composition (including the configuration) of the substances was determined by chiral-phase GC-MS of the hydrolysates. The sequences were established by EDMAN degradation following linearisation of the cyclic peptides upon treatment with LiAlH4. NMR spectroscopic studies of streptocidins C and D confirmed the proposed sequences and provided conformational data which indicate a molecular topology of streptocidins C and D similar to those of tyrocidine A and gramicidin S.