Protein hydrogels are of interest as biocompatible scaffolds or interfaces in sensors. We have used NMR methods to determine the structure and dynamics of protein hydrogels prepared from recombinant proteins selected for their mechanical and transport properties. The properties of hydrogels strongly depend on the crosslinking method, the degree of crosslinking and amino acid composition. The proteins of interest, suckerin 12 and reflectin from squid and the worm jaw protein NVJP1, are disordered in solution but have a tendency to self-assemble through β-sheet formation. The hydrogels were crosslinked using both selective and non-selective enzymatic methods. The effect of crosslinking with horseradish peroxidase, for example, is visible in the NMR spectra by a change in line widths, relaxation times and the disappearance of selected peaks in the swollen hydrogels. These effects allow the identification of crosslinking sites in hydrogels crosslinked with enzymes or metals. The dynamics of protein hydrogels were measured from the relaxation times and the rate of water diffusion through the gels.<br/>Suckerin 12 is of particular interest as a self-assembling hydrogel because of it is constructed of repeating sequence domain structures that resemble block copolymers. The role of the domains in self-assembly is examined by comparing the proton NMR spectra for the hydrogels with the amino acid probabilities. The spectra show narrow lines from the histidine, threonine and alanine that are most prevalent in the M1 domain and demonstrates that crosslinking occurs predominantly through the M2 domain. The properties of protein hydrogels are related to both the sequence and amino acid probabilities.

Structure and dynamics of protein hydrogels

255th National Meeting (2018)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.