1c4f

GREEN FLUORESCENT PROTEIN S65T AT PH 4.6

spinqualitylabelsall models 1c4f, resolution 2.25Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1c4f 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. NonStd Res: CRO 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 The green fluorescent protein (GFP) from the jellyfish Aequorea victoria has become a useful tool in molecular and cell biology. Recently, it has been found that the fluorescence spectra of most mutants of GFP respond rapidly and reversibly to pH variations, making them useful as probes of intracellular pH. To explore the structural basis for the titration behavior of the popular GFP S65T variant, we determined high-resolution crystal structures at pH 8.0 and 4.6. The structures revealed changes in the hydrogen bond pattern with the chromophore, suggesting that the pH sensitivity derives from protonation of the chromophore phenolate. Mutations were designed in yellow fluorescent protein (S65G/V68L/S72A/T203Y) to change the solvent accessibility (H148G) and to modify polar groups (H148Q, E222Q) near the chromophore. pH titrations of these variants indicate that the chromophore pKa can be modulated over a broad range from 6 to 8, allowing for pH determination from pH 5 to pH 9. Finally, mutagenesis was used to raise the pKa from 6.0 (S65T) to 7.8 (S65T/H148D). Unlike other variants, S65T/H148D exhibits two pH-dependent excitation peaks for green fluorescence with a clean isosbestic point. This raises the interesting possibility of using fluorescence at this isosbestic point as an internal reference. Practical real time in vivo applications in cell and developmental biology are proposed. Structural and spectral response of green fluorescent protein variants to changes in pH.,Elsliger MA, Wachter RM, Hanson GT, Kallio K, Remington SJ Biochemistry. 1999 Apr 27;38(17):5296-301. PMID:10220315 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Green Fluorescent Protein

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