Barrettides: A Peptide Family Specifically Produced by the Deep-Sea Sponge Geodia barretti

• Published in: Journal of Natural Products
• Main Authors: Steffen, Karin, Laborde, Quentin, Gunasekera, Sunithi, Payne, Colton D., Rosengren, K. Johan, Riesgo, Ana, Göransson, Ulf, Cárdenas, Paco
• Format: Text
• Language: English
• Published: American Chemical Society and American Society of Pharmacognosy 2021
• Subjects: North Atlantic
• Online Access: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8713285/; http://www.ncbi.nlm.nih.gov/pubmed/34874154; https://doi.org/10.1021/acs.jnatprod.1c00938

[Image: see text] Natural product discovery by isolation and structure elucidation is a laborious task often requiring ample quantities of biological starting material and frequently resulting in the rediscovery of previously known compounds. However, peptides are a compound class amenable to an alternative genomic, transcriptomic, and in silico discovery route by similarity searches of known peptide sequences against sequencing data. Based on the sequences of barrettides A and B, we identified five new barrettide sequences (barrettides C–G) predicted from the North Atlantic deep-sea demosponge Geodia barretti (Geodiidae). We synthesized, folded, and investigated one of the newly described barrettides, barrettide C (NVVPCFCVEDETSGAKTCIPDNCDASRGTNP, disulfide connectivity I–IV, II–III). Co-elution experiments of synthetic and sponge-derived barrettide C confirmed its native conformation. NMR spectroscopy and the anti-biofouling activity on larval settlement of the bay barnacle Amphibalanus improvisus (IC(50) 0.64 μM) show that barrettide C is highly similar to barrettides A and B in both structure and function. Several lines of evidence suggest that barrettides are produced by the sponge itself and not one of its microbial symbionts.