8a83 | pdb_00008a83

rsEGFP2 with a chlorinated chromophore in the fluorescent ON-state in a crystal dehydrated after illumination

spinqualitylabelsall models 8a83, resolution 1.81Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 8a83 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 1.81Å Ligands: OHD, SO4 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 Chromophore cis/trans photoisomerization is a fundamental process in chemistry and in the activation of many photosensitive proteins. A major task is understanding the effect of the protein environment on the efficiency and direction of this reaction compared to what is observed in the gas and solution phases. In this study, we set out to visualize the hula twist (HT) mechanism in a fluorescent protein, which is hypothesized to be the preferred mechanism in a spatially constrained binding pocket. We use a chlorine substituent to break the twofold symmetry of the embedded phenolic group of the chromophore and unambiguously identify the HT primary photoproduct. Through serial femtosecond crystallography, we then track the photoreaction from femtoseconds to the microsecond regime. We observe signals for the photoisomerization of the chromophore as early as 300 fs, obtaining the first experimental structural evidence of the HT mechanism in a protein on its femtosecond-to-picosecond timescale. We are then able to follow how chromophore isomerization and twisting lead to secondary structure rearrangements of the protein beta-barrel across the time window of our measurements. Serial Femtosecond Crystallography Reveals that Photoactivation in a Fluorescent Protein Proceeds via the Hula Twist Mechanism.,Fadini A, Hutchison CDM, Morozov D, Chang J, Maghlaoui K, Perrett S, Luo F, Kho JCX, Romei MG, Morgan RML, Orr CM, Cordon-Preciado V, Fujiwara T, Nuemket N, Tosha T, Tanaka R, Owada S, Tono K, Iwata S, Boxer SG, Groenhof G, Nango E, van Thor JJ J Am Chem Soc. 2023 Jul 7. doi: 10.1021/jacs.3c02313. PMID:37418747 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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