A serendipitous discovery of isomotuporin-containing sponge populations of Theonella swinhoei.

An in-depth LCMS examination of 14 different collections of Indo-Pacific Theonella swinhoei sponges resulted in the discovery of four diastereomeric analogues of the cyclic pentapeptide motuporin. These motuporin analogues all contain a novel 2R configuration for the Adda amino acid. Additionally, one analogue has a unique nonoxygenated Adda amino acid. In all, 15 different compounds were observed by LCMS or isolated. The stereochemistries of the constituent amino acids were determined through a combination of the advanced Marfey technique and 1H NMR data.