Abstract:
Ice nucleation protein (INP), which exists widely in nature, can induce water molecules to arrange regularly at micro scale resulting in elevated freezing point, but their tertiary structures have not been determined by experiments. The latest research shows that INP may interact with water molecules to promote the formation of ice nuclei through TXT template of central repeat region, which shares identical structural feature of antifreeze proteins but with larger template area and opposite functionalities. INP also has tyrosine (TYR) ladders to form new
β-helix dimer along dimerization interface, thus increasing the active surface area of protein ice. At the same time, in a series of control experiments, it was found that polyglycerol at a certain concentration obviously combined with the INP of ice nucleation bacteria
Pseudomonas syringae and inhibited its ice nucleation activity. In this work, molecular simulation software AutoDock was used to study the binding interaction of ice nucleation protein model of
Pseudomonas borealis with glycerol and triglycerol molecules, in order to discover the corresponding inhibition mechanism on ice nucleation proteins and its universality with other INPs. The binding information showed that the ligand molecules expressed different binding abilities to TXT template and tyrosine ladder, and other residues of ice nucleation proteins might participate in the binding with TXT freezing template.