3p4g | pdb_00003p4g

X-ray crystal structure of a hyperactive, Ca2+-dependent, beta-helical antifreeze protein from an Antarctic bacterium

spinqualitylabelsall models 3p4g, resolution 1.70Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3p4g is a 4 chain structure with sequence from Jcm 11775. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: ACT, CA, MG Gene: MpAFP (JCM 11775) Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed 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 both the primary prism and basal planes of ice and in effect provide an extensive X-ray crystallographic picture of the AFPice interaction. This unobstructed view, free from crystal-packing artefacts, shows the contributions of both the hydrophobic effect and hydrogen bonding during AFP adsorption to ice. We term this mode of binding the "anchored clathrate" mechanism of AFP action. Anchored clathrate waters bind antifreeze proteins to ice.,Garnham CP, Campbell RL, Davies PL Proc Natl Acad Sci U S A. 2011 Apr 11. PMID:21482800 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Antifreeze protein 3D structures

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