2h9w

Green fluorescent protein ground states: the influence of a second protonation site near the chromophore

spinqualitylabelsall models 2h9w, resolution 1.82Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2h9w 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: SO4 NonStd Res: CRO, CSD Gene: GFP (AEQVI) Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum 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 The photophysical properties of most green fluorescent protein mutants (GFPs) are strongly affected by pH. This effect must be carefully taken into account when using GFPs as fluorescent probes or indicators. Usually, the pH-dependence of GFPs is rationalized on the basis of the ionization equilibrium of the chromophore phenol group. Yet many different mutants show spectral behavior that cannot be explained by ionization of this group alone. In this study, we propose a general model of protonation comprising two ionization sites (2S model). Steady-state optical measurements at different pH and temperature and pH-jump relaxation experiments were combined to highlight the thermodynamic and kinetic properties of paradigmatically different GFP variants. Our experiments support the 2S model. For the case of mutants in which E222 is the second protonation site, thermodynamic coupling between this residue's and the chromophore's ionization reactions was demonstrated. In agreement with the 2S model predictions, X-ray analysis of one of these mutants showed the presence of two chromophore populations at high pH. Green fluorescent protein ground states: the influence of a second protonation site near the chromophore.,Bizzarri R, Nifosi R, Abbruzzetti S, Rocchia W, Guidi S, Arosio D, Garau G, Campanini B, Grandi E, Ricci F, Viappiani C, Beltram F Biochemistry. 2007 May 8;46(18):5494-504. Epub 2007 Apr 17. PMID:17439158 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Green Fluorescent Protein

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