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

Abstract

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.

Oceanographic setting influences the prokaryotic community and metabolome in deep-sea sponges

“…In the shallow water verongiid Aplysina aerophoba, bromotyrosine derivative variations are correlated with water temperature and season 92 , whereas our results suggested other factors associated with depth. The signals of bromotryptophane derivatives and barrettides A and B, as well as C 99 in G. barretti remained unaffected by depth.…”

Embracing the era of antimicrobial peptides with marine organisms

“…Barrettide is structurally similar to β-sheet AMPs with two disulfide bonds, but the antimicrobial activity has not been investigated yet except that barrettide C exhibited anti-biofouling activity. 69 Although many AMPs were claimed to be found in marine sponges, the sponges themselves are composed of a high amount of endosymbiotic bacteria, which account for up to 38% of sponge biomass. Therefore, the true origin of these AMPs is still in doubt which may be from the bacteria.…”

Whole genome sequence of the deep-sea sponge Geodia barretti (Metazoa, Porifera, Demospongiae)

“…This microbiota partly accounts for its richness in natural products ( Erngren et al . 2021 ; Steffen et al . 2021 ) with still many unknown bioactive metabolites.…”