Cutting Edge Structural Protein from the Jaws of Nereis virens

Abstract

The fang-like jaws of the marine polychaete Nereis Virens possess remarkable mechanical properties considering their high protein content and lack of mineralization. Hardness and stiffness properties in the jaw tip are comparable to human dentin and are achieved by extensive coordination of Zn 2+ by a histidine-rich protein framework. In the present study, the predominant protein in the jaw tip, NVjp-1, was purified and characterized by partial peptide mapping and molecular cloning of a partial cDNA from a jaw pulp library. The deduced amino acid sequence revealed an ∼38 kDa histidine-rich protein rich in glycine and histidine (∼36 and 27%, respectively) with no well-defined repetitive motifs. The effects of pH and metal treatment on aggregation, secondary structure, and hydrodynamic properties of recombinant Nvjp-1 are described. Notably, Zn treatment induced the formation of amyloid-like fibers.

RNA-Seq reveals a central role for lectin, C1q and von Willebrand factor A domains in the defensive glue of a terrestrial slug

“…Histidine is a common zinc and copper binding motif, and zinc is abundant in slug glue (Werneke et al 2007). Furthermore, the amino acid composition recalls the structure of the zinc-binding protein Nvjp-1a, which hardens the jaws of nereid worms (Broomell et al 2008). Nvjp-1a has 36% glycine and 27% histidine (Broomell et al 2008), which is similar to the 5’ end of the transcript for Asmp57a (45% gly and 21% his).…”

“…Furthermore, the amino acid composition recalls the structure of the zinc-binding protein Nvjp-1a, which hardens the jaws of nereid worms (Broomell et al 2008). Nvjp-1a has 36% glycine and 27% histidine (Broomell et al 2008), which is similar to the 5’ end of the transcript for Asmp57a (45% gly and 21% his). A similar proportion of glycine and histidine was found in spinalin, a protein implicated in strengthening the spines of cnidarian nematocysts (Koch et al 1998).…”

Marine hydroid perisarc: A chitin- and melanin-reinforced composite with DOPA–iron(III) complexes

“…3). Histidine, present at >10 mol.% levels in both squid beak and polychaete jaws, was less than 2 mol.% in the perisarc [1,4,7,8]. Another intriguing compound detected by the AA composition analysis was a broad peak at 40 min corresponding to glucosamine (Fig.…”

“…Both jaws have similar shapes and mechanical properties that resemble those of human dentin but without a similar reliance on mineral. Glycera jaws consist of melanin ($37 dry wt.%), protein ($50%), copper-based minerals and metal ions (up to 10%), whereas Nereis jaws are a composite of halogenated proteins (70-90% of the total dry mass) and metal ions [1,4,[6][7][8][9][10]. Melanin, which is usually associated with pigmentation, has significant load-bearing properties in Glycera jaw [2].…”

Modular peptides from the thermoplastic squid sucker ring teeth form amyloid-like cross-β supramolecular networks

“…[60] Both Ala and Gly-rich motifs also exhibit resemblance to peptide sequences from the wing cuticles of migratory locusts, [64] oyster shell matrix proteins (Pinctada genus) [65] and chicken claw keratins. [66] Finally, His-rich SRT motifs exhibit similarity to His-rich proteins [67] of the King ragworm jaw (Nereis virens), another hard tissues made of sclerotized proteins that are mechanically reinforced via His-Zn coordination bonds [68][69][70] and dense covalent cross-linking. [71,72] Generally speaking, our combinatorial assay showed that Ala-rich and His-rich peptides exhibit the strongest homo-peptidic interactions and such interactions are pH-dependent, being weaker under acidic conditions and the strongest near neutral pH.…”