Interpretation of crystallographic and mutational studies of antifreeze proteins
(AFPs) requires molecular modeling of AFPs with ice. Most models proposed so far
suggested H-bonds as the major driving force of AFP-ice association. However, the bulk
water offers optimal network of H-bonds and van der Waals contacts to the isolated AFP
and ice suggesting that corresponding components of free energy would not decrease
upon AFP-ice association. In an attempt to resolve this controversy, we Monte Carlominimized
complexes of several AFPs with taking into account, in addition to nonbonded
interactions and H-bonds, the hydration potential for proteins (Augspurger and Scheraga,
1996). Parameters of the hydration potential for ice were developed basing on an
assumption that at the melting temperature the free energy of water-ice association is
small. Simulations demonstrate that desolvation of hydrophobic groups in the AFPs upon
their fitting to the grooves at the ice surface presents the major stabilizing contributions to
the free energy of AFP-ice binding. Our results explain available data on structure of
AFPs and their mutational analyses, in particular, a paradoxical fact that substitution of
Thr residues to Val does not affect potency of Winter Flounder AFP. / Thesis / Master of Science (MS)
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/22702 |
| Date | 05 1900 |
| Creators | Jorov, Alexander |
| Contributors | Yang, Daniel S.C, Biochemistry |
| Source Sets | McMaster University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis |
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