AI Article Synopsis
- * One structure shows a 14-subunit LH1 ring that is open due to the presence of protein-W, while the other features a closed 16-subunit LH1 ring without the protein.
- * The findings reveal important details about how quinones interact with the RC-LH1 complex, including a new conformational change when quinones bind and the role of protein-W in facilitating faster quinone exchange by preventing the LH1 ring from closing.
Article Abstract
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 A 2.65-Å resolution structure of the RC-LH1-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-Å 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 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.
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| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7806223 | PMC |
| http://dx.doi.org/10.1126/sciadv.abe2631 | DOI Listing |
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