1hg7
From Proteopedia
High resolution structure of HPLC-12 type III antifreeze protein from Ocean Pout Macrozoarces americanus
Structural highlights
FunctionANP12_ZOAAM Contributes to protect fish blood from freezing at subzero sea water temperatures. Lowers the blood freezing point. Binds to nascent ice crystals and prevents further growth. Evolutionary ConservationCheck, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedType III antifreeze proteins (AFPs) are present in the body fluids of some polar fishes where they inhibit ice growth at subzero temperatures. Previous studies of the structure of type III AFP by NMR and X-ray identified a remarkably flat surface on the protein containing amino acids that were demonstrated to be important for interaction with ice by mutational studies. It was proposed that this protein surface binds onto the (1 0 [\bar 1] 0) plane of ice with the key amino acids interacting directly with the water molecules in the ice crystal. Here, we show that the mechanism of type III AFP interaction with ice crystals is more complex than that proposed previously. We report a high-resolution X-ray structure of type III AFP refined at 1.15 A resolution with individual anisotropic temperature factors. We report the results of ice-etching experiments that show a broad surface coverage, suggesting that type III AFP binds to a set of planes that are parallel with or inclined at a small angle to the crystallographic c-axis of the ice crystal. Our modelling studies, performed with the refined structure, confirm that type III AFP can make energetically favourable interactions with several ice surfaces. Understanding the mechanism of ice binding by type III antifreeze proteins.,Antson AA, Smith DJ, Roper DI, Lewis S, Caves LS, Verma CS, Buckley SL, Lillford PJ, Hubbard RE J Mol Biol. 2001 Jan 26;305(4):875-89. PMID:11162099[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
|
Categories: Large Structures | Zoarces americanus | Antson AA | Buckley SL | Caves LSD | Hubbard RE | Lewis S | Lillford PJ | Roper DI | Smith DJ | Verma CS