8z82

Photosynthetic LH1-RC-HiPIP complex from the purple bacterium Halorhodospira halophila

spinqualitylabelsall models 8z82, resolution 2.40Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 8z82 is a 37 chain structure with sequence from Halorhodospira halophila. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: Electron Microscopy, Resolution 2.4Å Ligands: BPH, CDL, CRT, FE, HEC, LMT, MG, MQ8, PGV, PLM, UQ8, Z41 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function A1WXF5_HALHL The reaction center of purple bacteria contains a tightly bound cytochrome molecule which re-reduces the photo oxidized primary electron donor.[ARBA:ARBA00003196][PIRNR:PIRNR000017] Publication Abstract from PubMed Halorhodospira (Hlr.) halophila strain BN9622 is an extremely halophilic and alkaliphilic purple phototrophic bacterium and has been widely used as a model for exploring the osmoadaptive and photosynthetic strategies employed by phototrophic extreme halophiles that enable them to thrive in hypersaline environments. Here we present the cryo-EM structures of (1) a unique native Hlr. halophila triple-complex formed from light-harvesting (LH1), the reaction center (RC), and high-potential iron-sulfur protein (HiPIP) at 2.44 A resolution, and (2) a HiPIP-free LH1-RC complex at 2.64 A resolution. Differing from the LH1 in the Hlr. halophila LH1-LH2 co-complex where LH1 encircles LH2, the RC-associated LH1 complex consists of 16 (rather than 18) alphabeta-subunits circularly surrounding the RC. These distinct forms of LH1 indicate that the number of subunits in a Hlr. halophila LH1 complex is flexible and its size is a function of the photocomplex it encircles. Like LH1 in the LH1-LH2 co-complex, the RC-associated LH1 complex also contained two forms of alphabeta-polypeptides and both dimeric and monomeric molecules of bacteriochlorophyll a. The majority of the isolated Hlr. halophila LH1-RC complexes contained the electron donor HiPIP bound to the surface of the RC cytochrome subunit near the heme-1 group. The bound HiPIP consisted of an N-terminal functional domain and a long C-terminal extension firmly attached to the cytochrome subunit. Despite overall highly negative surface-charge distributions for both the cytochrome subunit and HiPIP, the interface between the two proteins was relatively uncharged and neutral, forming a pathway for electron tunneling. The structure of the Hlr. halophila LH1-RC-HiPIP complex provides insights into the mechanism of light energy acquisition coupled with a long-distance electron donating process toward the charge separation site in a multi-extremophilic phototroph. A Native LH1-RC-HiPIP Supercomplex from an Extremophilic Phototroph.,Tani K, Kanno R, Nagashima KVP, Kawakami M, Hiwatashi N, Nakata K, Nagashima S, Inoue K, Takaichi S, Purba ER, Hall M, Yu LJ, Madigan MT, Mizoguchi A, Humbel BM, Kimura Y, Wang-Otomo ZY Commun Biol. 2025 Jan 11;8(1):42. doi: 10.1038/s42003-024-07421-w. PMID:39799244 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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