FIGURE 7.

Dashed lines indicate a quorum of anchored clathrate waters organized by each of the four ranks of threonine residues. All four water patterns, any of which could potentially independently bind the AFP to ice, are illustrated. Crystallographic waters are in red; simulation waters are in pink. Dashed lines (black) represent potential hydrogen bonds (within 2.4–3.5 Å). It is unlikely that more than two ranks of anchored clathrate waters can simultaneously fit well to either the primary prism or basal plane of ice.