Gombamide A, a Cyclic Thiopeptide from the Sponge Clathria gombawuiensis

Abstract

A new peptide, gombamide A (1), was isolated from the marine sponge Clathria gombawuiensis, collected from Korean waters. Based on the results of combined spectroscopic analyses, the structure of this compound was determined to be a cyclic C-terminally-modified thiohexapeptide containing the unusual amino acid residues para-hydroxystyrylamide (pHSA) and pyroglutamicacid (pyroGlu). The absolute configurations of all amino acid residues were determined to be L by advanced Marfeys analysis. The new compound exhibited weak cytotoxicity against A549 and K562 cell lines as well as moderate inhibitory activity against Na+/K+-ATPase.