1ops | pdb_00001ops

ICE-BINDING SURFACE ON A TYPE III ANTIFREEZE PROTEIN FROM OCEAN POUT

spinqualitylabelsall models 1ops, resolution 2.00Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1ops is a 1 chain structure with sequence from Macrozoarces americanus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [ANP1_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 (By similarity). Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed Antifreeze proteins (AFPs) adsorb to surfaces of growing ice crystals, thereby arresting their growth. The prevailing hypothesis explains the nature of adsorption in terms of a match between the hydrophilic side chains on the AFP's ice-binding surface (IBS) and the water molecules on the ice surface. The number and spatial arrangement of hydrogen bonds thus formed have been proposed to account, respectively, for the binding affinity and specificity. The crystal structure of a type III AFP from ocean pout (isoform HPLC-3) has been determined to 2.0-A resolution. The structure reveals an internal dyad motif formed by two 19-residue, loop-shaped elements. Based on of the flatness observed on the type I alpha-helical AFP's IBS, an automated algorithm was developed to analyze the surface planarity of the globular type III AFP and was used to identify the IBS on this protein. The surface with the highest flatness score is formed by one loop of the dyad motif and is identical to the IBS deduced from earlier mutagenesis studies. Interestingly, 67% of this surface contains nonpolar solvent-accessible surface area. The success of our approach to identifying the IBS on an AFP, without considering the presence of polar side chains, indicates that flatness is the first approximation of an IBS. We further propose that the specificity of interactions between an IBS and a particular ice-crystallographic plane arises from surface complementarity. Identification of the ice-binding surface on a type III antifreeze protein with a "flatness function" algorithm.,Yang DS, Hon WC, Bubanko S, Xue Y, Seetharaman J, Hew CL, Sicheri F Biophys J. 1998 May;74(5):2142-51. PMID:9591641 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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