6t39

Crystal structure of rsEGFP2 in its off-state determined by SFX

spinqualitylabelsall models 6t39, resolution 1.60Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 6t39 is a 1 chain structure with sequence from Aequorea victoria. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.6Å Ligands: PIA 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. Publication Abstract from PubMed Reversibly switchable fluorescent proteins (RSFPs) serve as markers in advanced fluorescence imaging. Photoswitching from a non-fluorescent off-state to a fluorescent on-state involves trans-to-cis chromophore isomerization and proton transfer. Whereas excited-state events on the ps timescale have been structurally characterized, conformational changes on slower timescales remain elusive. Here we describe the off-to-on photoswitching mechanism in the RSFP rsEGFP2 by using a combination of time-resolved serial crystallography at an X-ray free-electron laser and ns-resolved pump-probe UV-visible spectroscopy. Ten ns after photoexcitation, the crystal structure features a chromophore that isomerized from trans to cis but the surrounding pocket features conformational differences compared to the final on-state. Spectroscopy identifies the chromophore in this ground-state photo-intermediate as being protonated. Deprotonation then occurs on the mus timescale and correlates with a conformational change of the conserved neighbouring histidine. Together with a previous excited-state study, our data allow establishing a detailed mechanism of off-to-on photoswitching in rsEGFP2. Photoswitching mechanism of a fluorescent protein revealed by time-resolved crystallography and transient absorption spectroscopy.,Woodhouse J, Nass Kovacs G, Coquelle N, Uriarte LM, Adam V, Barends TRM, Byrdin M, de la Mora E, Bruce Doak R, Feliks M, Field M, Fieschi F, Guillon V, Jakobs S, Joti Y, Macheboeuf P, Motomura K, Nass K, Owada S, Roome CM, Ruckebusch C, Schiro G, Shoeman RL, Thepaut M, Togashi T, Tono K, Yabashi M, Cammarata M, Foucar L, Bourgeois D, Sliwa M, Colletier JP, Schlichting I, Weik M Nat Commun. 2020 Feb 6;11(1):741. doi: 10.1038/s41467-020-14537-0. PMID:32029745 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Green Fluorescent Protein 3D structures

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