3P043 Mutagenesis study of an antifreeze protein isoform from a snow-mold fungus, Typhula ishikariensis(01B. Protein: Structure & Function,Poster,The 52nd Annual Meeting of the Biophysical Society of Japan(BSJ2014))

Antifreeze proteins (AFPs) facilitate cold-survival of the organisms living under freezing environment by inhibiting ice crystal growth. In this study, we focused on a fungal AFP denoted TisAFP secreted from a psychrophilic snow-mold fungus, Typhula ishikariensis. It reported seven isoforms of TisAFP that share a high sequence identity. Significantly, fluorescencebased ice plane affinity (FIPA) analysis showed that the ice binding specificity of TisAFP8 is quite different from the others. To clarify what determines the uniqueness of TisAFP8, we performed mutagenesis experiments on TisAFP8, especially on the residues constructing its putative ice-binding site. The data suggested an importance of inward pointing residues not just outward pointing residues of TisAFP8.