Psychrophilic Arctic yeast Leucosporidium sp. produces a glycosylated ice-binding protein (LeIBP) with a molecular mass of approximately 25 kDa, which can lower the freezing point below the melting point once it binds to ice. LeIBP exhibits low amino acid sequence similarity to other antifreeze proteins with known protein structures. Recently, we developed an expression system allowing high-level production and efficient purification of recombinant pLeIBP. Furthermore, crystallization and preliminary X-ray crystallographic analysis of the ice-binding protein were performed.
To investigate the antifreeze mechanism of LeIBP, we have carried out structural studies. As the first step toward its structural elucidation, we report the results of preliminary X-ray crystallographic experiments with LeIBP.