Characterization of Zinc-Histidine Interactions in Nvjp-1

The mandible of Nereis virens, a marine sandworm, is mostly organic with stiffness and hardness comparable to that of human dentin. Nvjp-1 is the primary protein in the Nereis jaw and is inherently Histidine rich. Histidine contributes to the stability of the protein structure and superior mechanical properties through metal-coordinate bonds. Crosslinking of purified recombinant Nvjp-1 creates a water stable hydrogel that is capable of expanding and contracting upon exposure to various ions. Nvjp-1 hydrogels exhibit sclerotization through metal-coordination with divalent cations. Over ninety percent of the amino acid sequence of the carboxy-terminal of Nvjp-1 is comprised of only four amino acids. In order to determine the genetic/protein motifs directly responsible for the mechanical response, a carboxy-terminal truncation mutant of Nvjp-1 was recombinately expressed and crosslinked to form hydrogels. Dynamic mechanical analysis was performed on the carboxy-terminal truncation mutant to compare its mechanical properties to that of the full-length protein. De Novo structure prediction was performed using Molecular Dynamics simulations as a technique for determining native protein structures. The role of Zn-Histidine interactions in Nvjp-1 and their effect on protein structure was also investigated