Abstract
Antifreeze protein (AFP) specifically binds to ice crystal surface and inhibits its growth. In order to elucidate ice-binding mechanism of fungal AFPs, we performed measurements of thermal hysteresis (TH) activity and a recently developed method called "Fluorescence-based Ice Plane Affinity (FIPA)" analysis against AFP identified from Antarctic ascomycete, Antarctomyces psychrotrophicus (AnpAFP). AnpAFP showed a maximum TH of 0.8℃ and led to an ice growth along with the c-axis, which were typical for AFP with moderate antifreeze activity. In addition, FIPA analysis showed that AnpAFP bound to only prism planes of an ice crystal. Such an ice-binding manner of AnpAFP is different from that of the other known microbial AFPs, since they can bind to both prism and basal planes.
