8gn2

Crystal structure of PPBQ-bound photosystem II complex

spinqualitylabelsall models 8gn2, resolution 1.95Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 8gn2 is a 20 chain structure with sequence from Thermostichus vulcanus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.95Å Ligands: BCR, BCT, CA, CL, CLA, DGD, DMS, FE2, FME, GOL, HEC, HEM, HSK, HTG, K3C, LHG, LMG, LMT, MG, OEX, PHO, PL9, RRX, SQD, UNL Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function PSBA_THEVL D1 (PsbA) and D2 (PsbD) bind P680, the primary electron donor of photosystem II (PSII) as well as electron acceptors. PSII is a light-driven water plastoquinone oxidoreductase, using light energy to abstract electrons from H(2)O, generating a proton gradient subsequently used for ATP formation.[HAMAP-Rule:MF_01379] Publication Abstract from PubMed Photosystem II (PSII) utilizes light energy to split water, and the electrons extracted from water are transferred to Q(B), a plastoquinone molecule bound to the D1 subunit of PSII. Many artificial electron acceptors (AEAs) with molecular structures similar to that of plastoquinone can accept electrons from PSII. However, the molecular mechanism by which AEAs act on PSII is unclear. Here, we solved the crystal structure of PSII treated with three different AEAs, 2,5-dibromo-1,4-benzoquinone, 2,6-dichloro-1,4-benzoquinone, and 2-phenyl-1,4-benzoquinone, at 1.95 to 2.10 A resolution. Our results show that all AEAs substitute for Q(B) and are bound to the Q(B)-binding site (Q(B) site) to receive electrons, but their binding strengths are different, resulting in differences in their efficiencies to accept electrons. The acceptor 2-phenyl-1,4-benzoquinone binds most weakly to the Q(B) site and showed the highest oxygen-evolving activity, implying a reverse relationship between the binding strength and oxygen-evolving activity. In addition, a novel quinone-binding site, designated the Q(D) site, was discovered, which is located in the vicinity of Q(B) site and close to Q(C) site, a binding site reported previously. This Q(D) site is expected to play a role as a channel or a storage site for quinones to be transported to the Q(B) site. These results provide the structural basis for elucidating the actions of AEAs and exchange mechanism of Q(B) in PSII and also provide information for the design of more efficient electron acceptors. Structural insights into the action mechanisms of artificial electron acceptors in photosystem II.,Kamada S, Nakajima Y, Shen JR J Biol Chem. 2023 May 19;299(7):104839. doi: 10.1016/j.jbc.2023.104839. PMID:37209822 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Photosystem II 3D structures

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