The structures and functions of ice crystal-controlling proteins from bacteria.
Many organisms have evolved into unique mechanisms which minimize freezing injury due to extracellular ice formation. Specifically, certain bacteria have produced a few proteins each with different functions. For example, the ice nucleation protein acts as a template for ice formation, which is responsible for imparting ice nucleating activity. The anti-nucleating protein inhibits the fluctuation of ice nucleus formation by a foreign particle in the water drop. Also, the antifreeze proteins depress the freezing temperature, modify or suppress ice crystal growth, inhibit ice recrystallization, and protect the cell membrane from cold-induced damage. In this article, a review on the current knowledge of the structure and the function of these three types of proteins, which are capable of interacting with ice itself or its nuclei from bacteria.
Kawahara
Hidehisa
H
Department of Biotechnology, Faculty of Engineering, Kansai University, 3-3-35 Yamate-cho, Suita, Osaka 564-8680, Japan. kawahara@ipcku.kansai-u.ac.jp