3ir8

Red fluorescent protein mKeima at pH 7.0

spinqualitylabelsall models 3ir8, resolution 1.63Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3ir8 is a 2 chain structure with sequence from Montipora sp. 20. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. NonStd Res: CRQ Gene: m-keima (Montipora sp. 20) Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT 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 mKeima is an unusual monomeric red fluorescent protein (lambda(em)(max) approximately 620 nm) that is maximally excited in the blue (lambda(ex)(max) approximately 440 nm). The large Stokes shift suggests that the chromophore is normally protonated. A 1.63 A resolution structure of mKeima reveals the chromophore to be imbedded in a novel hydrogen bond network, different than in GFP, which could support proton transfer from the chromophore hydroxyl, via Ser142, to Asp157. At low temperatures the emission contains a green component (lambda(em)(max) approximately 535 nm), enhanced by deuterium substitution, presumably resulting from reduced proton transfer efficiency. Ultrafast pump/probe studies reveal a rising component in the 610 nm emission with a lifetime of approximately 4 ps, characterizing the rate of proton transfer. Mutation of Asp157 to neutral Asn changes the chromophore resting charge state to anionic (lambda(ex)(max) approximately 565 nm, lambda(em)(max) approximately 620 nm). Thus, excited state proton transfer (ESPT) explains the large Stokes shift. This work unambiguously characterizes green emission from the protonated acylimine chromophore of red fluorescent proteins. Excited State Proton Transfer in the Red Fluorescent Protein mKeima.,Henderson JN, Osborn MF, Koon N, Gepshtein R, Huppert D, Remington SJ J Am Chem Soc. 2009 Aug 26. PMID:19708654 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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