6ozb | pdb_00006ozb

Crystal structure of the phycoerythrobilin-bound GAF domain from a cyanobacterial phytochrome

spinqualitylabelsall models 6ozb, resolution 1.80Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 6ozb is a 3 chain structure with sequence from Nostoc sp. PCC 7120 = FACHB-418. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.8Å Ligands: PEB Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function Q8YTL8_NOSS1 Publication Abstract from PubMed Phytochromes are a diverse family of bilin-binding photoreceptors that regulate a wide range of physiological processes. Their photochemical properties make them attractive for applications in optogenetics and superresolution microscopy. Phytochromes undergo reversible photoconversion triggered by the Z right arrow over left arrow E photoisomerization about the double bond in the bilin chromophore. However, it is not fully understood at the molecular level how the protein framework facilitates the complex photoisomerization dynamics. We have studied a single-domain bilin-binding photoreceptor All2699g1 (Nostoc sp. PCC 7120) that exhibits photoconversion between the red light-absorbing (Pr) and far red-absorbing (Pfr) states just like canonical phytochromes. We present the crystal structure and examine the photoisomerization mechanism of the Pr form as well as the formation of the primary photoproduct Lumi-R using time-resolved spectroscopy and hybrid quantum mechanics/molecular mechanics simulations. We show that the unusually long excited state lifetime (broad lifetime distribution centered at approximately 300 picoseconds) is due to the interactions between the isomerizing pyrrole ring D and an adjacent conserved Tyr142. The decay kinetics shows a strongly distributed character which is imposed by the nonexponential protein dynamics. Our findings offer a mechanistic insight into how the quantum efficiency of the bilin photoisomerization is tuned by the protein environment, thereby providing a structural framework for engineering bilin-based optical agents for imaging and optogenetics applications. The interplay between chromophore and protein determines the extended excited state dynamics in a single-domain phytochrome.,Slavov C, Fischer T, Barnoy A, Shin H, Rao AG, Wiebeler C, Zeng X, Sun Y, Xu Q, Gutt A, Zhao KH, Gartner W, Yang X, Schapiro I, Wachtveitl J Proc Natl Acad Sci U S A. 2020 Jun 26. pii: 1921706117. doi:, 10.1073/pnas.1921706117. PMID:32591422 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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