Scyptolin A and B, cyclic depsipeptides from axenic cultures of Scytonema hofmanni PCC 7110. |
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| Authors: | U Matern L Oberer R A Falchetto M Erhard W A K?nig M Herdman J Weckesser |
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| Affiliation: | Institut für Biologie II (Mikrobiologie), Albert-Ludwigs-Universit?t, Sch?nzlestrasse 1, D-79104 Freiburg i. Br., Germany. matern@uni-freiburg.de |
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| Abstract: | Two novel cyclic depsipeptides were isolated from axenic cultures of the terrestrial cyanobacterium Scytonema hofmanni PCC 7110 and designated scyptolin A and B. Amino acid analyses in context with mass and 1H/13C NMR spectroscopies revealed a composition typical for heterologous cyanopeptolins but containing the uncommon residue 3'-chloro-N-methyl-Tyr (cmTyr) and a unique sidechain. Scyptolin A and B both consist of the N-acylated peptide But(1)-Ala(2)-Thr(3)-Thr(4)-Leu(5)-Ahp(6) (3-amino-6-hydroxy-2-oxo-1-piperidine)-Thr(7)-cmTyr(8)-Val(9), which forms a 19-membered ring by esterification of the carboxyl of Val(9) with the hydroxyl of Thr(4). In scyptolin B, the hydroxyl of the Thr(3) residue is additionally esterified with N-butyroyl-Ala. Both scyptolin A and B exhibit selective inhibition of porcine pancreatic elastase in vitro with IC(50) values of 3.1 microg/ml. |
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