Anchored clathrate waters bind antifreeze proteins to ice.

ABSTRACT: The mechanism by which antifreeze proteins (AFPs) irreversibly bind to ice has not yet been resolved. The ice-binding site of an AFP is relatively hydrophobic, but also contains many potential hydrogen bond donors/acceptors. The extent to which hydrogen bonding and the hydrophobic effect contribute to ice binding has been debated for over 30 years. Here we have elucidated the ice-binding mechanism through solving the first crystal structure of an Antarctic bacterial AFP. This 34-kDa domain, the largest AFP structure determined to date, folds as a Ca(2+)-bound parallel beta-helix with an extensive array of ice-like surface waters that are anchored via hydrogen bonds directly to the polypeptide backbone and adjacent side chains. These bound waters make an excellent three-dimensional match to

SUBMITTER: Garnham CP 

PROVIDER: S-EPMC3088597 | biostudies-literature | 2011 May

REPOSITORIES: biostudies-literature