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Publication Abstract from PubMed

The reaction-center light-harvesting complex 1 (RC-LH1) is the core photosynthetic component in purple phototrophic bacteria. We present two cryo-electron microscopy structures of RC-LH1 complexes from Rhodopseudomonas palustris A 2.65-A resolution structure of the RC-LH1(14)-W complex consists of an open 14-subunit LH1 ring surrounding the RC interrupted by protein-W, whereas the complex without protein-W at 2.80-A resolution comprises an RC completely encircled by a closed, 16-subunit LH1 ring. Comparison of these structures provides insights into quinone dynamics within RC-LH1 complexes, including a previously unidentified conformational change upon quinone binding at the RC Q(B) site, and the locations of accessory quinone binding sites that aid their delivery to the RC. The structurally unique protein-W prevents LH1 ring closure, creating a channel for accelerated quinone/quinol exchange.

Structures of Rhodopseudomonas palustris RC-LH1 complexes with open or closed quinone channels.,Swainsbury DJK, Qian P, Jackson PJ, Faries KM, Niedzwiedzki DM, Martin EC, Farmer DA, Malone LA, Thompson RF, Ranson NA, Canniffe DP, Dickman MJ, Holten D, Kirmaier C, Hitchcock A, Hunter CN Sci Adv. 2021 Jan 13;7(3):eabe2631. doi: 10.1126/sciadv.abe2631. Print 2021 Jan. PMID:33523887^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.