THE DYNAMICS AND BINDING OF A TYPE-III ANTIFREEZE PROTEIN IN WATER AND ON ICE

Certain plants, insects and fish living in cold environments prevent t issue damage from freezing by producing antifreeze proteins or antifre eze glycoproteins [1]. These proteins work by inhibiting ice growth be low the normal equilibrium freezing point of water. Fish antifreeze pr oteins are categorized into helical Type I AFPs, cysteine rich globula r Type II AFPs, and small globular Type III AFPs. A three dimensional structure of Type III antifreeze protein was determined recently by NM R spectroscopy [2]. Using this solution structure we performed a 110 p s molecular dynamics simulation in a 50 x 50 x 50 Angstrom box of TIP3 P water. Structural, dynamical and protein-water interactions during t he simulation were investigated and are reported in this article. In a ddition, the dynamics structure was used to investigate possible prote in-ice binding interactions. In particular, the protein face proposed by Chao et al. [3] was modeled on the (100) ice face and is discussed in terms of protein-ice interactions.