9ins

MONOVALENT CATION BINDING IN CUBIC INSULIN CRYSTALS

spinqualitylabelsall models 9ins, resolution 1.70Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 9ins is a 2 chain structure with sequence from Pig. 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 [INS_PIG] Insulin decreases blood glucose concentration. It increases cell permeability to monosaccharides, amino acids and fatty acids. It accelerates glycolysis, the pentose phosphate cycle, and glycogen synthesis in liver. 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 Two localized monovalent cation binding sites have been identified in cubic insulin from 2.8 A-resolution difference electron density maps comparing crystals in which the Na+ ions have been replaced by Tl+. One cation is buried in a closed cavity between insulin dimers and is stabilized by interaction with protein carbonyl dipoles in two juxtaposed alternate positions related by the crystal dyad. The second cation binding site, which also involves ligation with carbonyl dipoles, is competitively occupied by one position of two alternate His B10 side chain conformations. The cation occupancy in both sites depends on the net charge on the protein which was varied by equilibrating crystals in the pH range 7-10. Detailed structures of the cation binding sites were inferred from the refined 2-A resolution map of the sodium-insulin crystal at pH 9. At pH 9, the localized monovalent cations account for less than one of the three to four positive counterion charges necessary to neutralize the negative charge on each protein molecule. The majority of the monovalent counterions are too mobile to show up in the electron density maps calculated using data only at resolution higher than 10 A. Monovalent cations of ionic radius less than 1.5 A are required for crystal stability. Replacing Na+ with Cs+, Mg++, Ca++ or La+++ disrupts the lattice order, but crystals at pH 9 with 0.1 M Li+, K+, NH4+, Rb+ or Tl+ diffract to at least 2.8 A resolution. Monovalent cation binding to cubic insulin crystals.,Gursky O, Li Y, Badger J, Caspar DL Biophys J. 1992 Mar;61(3):604-11. PMID:1504238 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also PDB identification code User:Eric Martz/Introduction to Structural Bioinformatics 2016 User:Eric Martz/Introduction to Structural Bioinformatics I User:Eric Martz/Introduction to Structural Bioinformatics I%2C 2014

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