8qfh

Room temperature crystal structure of the Photoactivated Adenylate Cyclase OaPAC with ATP bound

spinqualitylabelsall models 8qfh, resolution 1.80Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 8qfh is a 1 chain structure with sequence from Oscillatoria acuminata PCC 6304. 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: ATP, FMN, MG Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function K9TLZ5_9CYAN Publication Abstract from PubMed The understanding of signal transduction mechanisms in photoreceptor proteins is essential for elucidating how living organisms respond to light as environmental stimuli. In this study, we investigated the ATP binding, photoactivation and signal transduction process in the photoactivatable adenylate cyclase from Oscillatoria acuminata (OaPAC) upon blue light excitation. Structural models with ATP bound in the active site of native OaPAC at cryogenic as well as room temperature are presented. ATP is found in one conformation at cryogenic- and in two conformations at ambient-temperature, and is bound in an energetically unfavorable conformation for the conversion to cAMP. However, FTIR spectroscopic experiments confirm that this conformation is the native binding mode in dark state OaPAC and that transition to a productive conformation for ATP turnover only occurs after light activation. A combination of time-resolved crystallography experiments at synchrotron and X-ray Free Electron Lasers sheds light on the early events around the Flavin Adenine Dinucleotide (FAD) chromophore in the light-sensitive BLUF domain of OaPAC. Early changes involve the highly conserved amino acids Tyr6, Gln48 and Met92. Crucially, the Gln48 side chain performs a 180 degrees rotation during activation, leading to the stabilization of the FAD chromophore. Cryo-trapping experiments allowed us to investigate a late light-activated state of the reaction and revealed significant conformational changes in the BLUF domain around the FAD chromophore. In particular, a Trp(in)/Met(out) transition upon illumination is observed for the first time in the BLUF domain and its role in signal transmission via alpha-helix 3 and 4 in the linker region between sensor and effector domain is discussed. Light-induced Trp(in)/Met(out) Switching During BLUF Domain Activation in ATP-bound Photoactivatable Adenylate Cyclase OaPAC.,Chretien A, Nagel MF, Botha S, de Wijn R, Brings L, Dorner K, Han H, Koliyadu JCP, Letrun R, Round A, Sato T, Schmidt C, Secareanu RC, von Stetten D, Vakili M, Wrona A, Bean R, Mancuso A, Schulz J, Pearson AR, Kottke T, Lorenzen K, Schubert R J Mol Biol. 2024 Mar 1;436(5):168439. doi: 10.1016/j.jmb.2024.168439. Epub 2024 , Jan 5. PMID:38185322 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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