Behavior of antifreeze proteins and glycoproteins at the ice/solution interface and ice growth kinetics during one-directional growth

COMP 17

Yoshinori Furukawa, frkw@lowtem.hokudai.ac.jp1, Salvador Zepeda1, Hiroyuki Nakaya1, Yukihiro Uda, y-uda@pop.lowtem.hokudai.ac.jp1, and Etsuro Yokoyama, yokoyama@gakushuin.ac.jp2. (1) ILTS, Hokkaido University, Kita19 Nishi8, Kita-ku, Sapporo, Japan, (2) Computer Center, Gakushuin University, 1-5-1 Mejiro, Toshima-ku, Tokyo, Japan
To observe the distribution of antifreeze proteins (AFPs) and glycoproteins (AFGPs) at the ice/water interface, one-directional ice growth experiments were carried out with FITC labeled antifreeze protein solutions. Fluorescence images clearly show the accumulation, distribution, and incorporation of AFGPs at the interface. For AFGPs, at slow growth velocities the interface is flat and the proteins accumulate at the interface and are entirely rejected from the crystal. At higher velocities the interface breaks up and forms finger structures with the proteins incorporating into veins formed between the ice fingers and none in the crystal matrix contrary to previously accepted paradigms for AFGP mechanism, namely a strong irreversible binding between the ice and protein. From the decay processes of the diffusion field after growth is stopped, we determined the diffusion and segregation coefficients of AFGPs in the solution.coefficients of AFGPs in the solution.
 

Antifreeze Proteins: A Memorial Symposium for Robert Feeney
8:30 AM-12:05 PM, Sunday, August 19, 2007 BCEC -- 162A, Oral

Division of Computers in Chemistry

The 234th ACS National Meeting, Boston, MA, August 19-23, 2007