2o24 | pdb_00002o24

Spectroscopic and Structural Study of the Heterotropic Linkage between Halide and Proton Ion Binding to Gfp Proteins: E2(GFP)-Cl Complex

spinqualitylabelsall models 2o24, resolution 1.45Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2o24 is a 1 chain structure with sequence from Aeqvi. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: CL NonStd Res: CRO Related: 2h6v, 2o29, 2o2b Gene: GFP (AEQVI) Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [GFP_AEQVI] Energy-transfer acceptor. Its role is to transduce the blue chemiluminescence of the protein aequorin into green fluorescent light by energy transfer. Fluoresces in vivo upon receiving energy from the Ca(2+)-activated photoprotein aequorin. 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 This study reports the influence of halogens on fluorescence properties of the Aequorea victoria Green Fluorescent Protein variant S65T/T203Y (E(2)GFP). Halide binding forms a specific nonfluorescent complex generating a substantial drop of the fluorescence via static quenching. Spectroscopic analysis under different solution conditions reveals high halogen affinity, which is strongly dependent on the pH. This evidences the presence in E(2)GFP of interacting binding sites for halide ions and for protons. Thermodynamic link and cooperative interaction are assessed demonstrating that binding of one halide ion is associated with the binding of one proton in a cooperative fashion with the formation, in the pH range 4.5-10, of a single fully protonated E(2)GFP.halogen complex. To resolve the structural determinants of E(2)GFP sensitivity to halogens, high-resolution crystallographic structures were obtained for the halide-free and I(-), Br(-), and Cl(-) bound E(2)GFP. Remarkably the first high-resolution (1.4 A) crystallographic structure of a chloride-bound GFP is reported. The chloride ion occupies a specific and unique binding pocket in direct contact (3.4 A) with the chromophore imidazolidinone aromatic ring. Unanticipated flexibility, strongly modulated by halide ion interactions, is observed in the region surrounding the chromophore. Furthermore molecular dynamics simulations identified E222 residue (along with the chromophore Y66 residue) being in the protonated state when E(2)GFP.halogen complex is formed. The impact of these results on high-sensitivity biosensor design will be discussed. Spectroscopic and structural study of proton and halide ion cooperative binding to gfp.,Arosio D, Garau G, Ricci F, Marchetti L, Bizzarri R, Nifosi R, Beltram F Biophys J. 2007 Jul 1;93(1):232-44. Epub 2007 Apr 13. PMID:17434942 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Green Fluorescent Protein 3D structures

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