Interaction between anti-freeze protein and ice: dynamics of diffusion and adsorption

2017 Fiscal Year Final Research Report

• Project/Area Number: 16K13672
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Crystal engineering
• Research Institution: Hokkaido University
• Principal Investigator: Sazaki Gen 北海道大学, 低温科学研究所, 教授 (60261509)
• Research Collaborator: VORONTSOV DMITRY ; BAYER MADDALENA
• Project Period (FY): 2016-04-01 – 2018-03-31
• Keywords: 不凍タンパク質 / レーザー共焦点蛍光観察 / 吸着

Outline of Final Research Achievements

We prepared two kinds of fluorescent-labeled anti-freeze proteins, AFP-III from polar fish and fc-AFP from sea ice algae, by chemical modification and genetic engineering, respectively. Then we studied the adsorption of these AFPs on ice crystal surfaces and their effects on the growth of ice crystals using a laser confocal fluorescence microscope and a Mach-Zehnder interferometer. We found that AFP-III adsorbs specifically on ice prism faces but not on ice basal faces, and that fc-AFP adsorbs on both ice prism and basal faces. These results agree well with the effects of these AFPs on the growth of ice crystals: the growth of ice crystals in the crystallographic c-direction is promoted by AFP-III but suppressed by fc-AFP significantly. In this study, we revealed for the first time that different AFPs with different affinities with ice crystal surfaces show different effects on the growth of ice crystals.

Free Research Field

結晶成長学