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Publication Abstract from PubMed

Bacterial polysulfide reductase (PsrABC) is an integral membrane protein complex responsible for quinone-coupled reduction of polysulfide, a process important in extreme environments such as deep-sea vents and hot springs. We determined the structure of polysulfide reductase from Thermus thermophilus at 2.4-A resolution, revealing how the PsrA subunit recognizes and reduces its unique polyanionic substrate. The integral membrane subunit PsrC was characterized using the natural substrate menaquinone-7 and inhibitors, providing a comprehensive representation of a quinone binding site and revealing the presence of a water-filled cavity connecting the quinone binding site on the periplasmic side to the cytoplasm. These results suggest that polysulfide reductase could be a key energy-conserving enzyme of the T. thermophilus respiratory chain, using polysulfide as the terminal electron acceptor and pumping protons across the membrane via a previously unknown mechanism.

Molecular mechanism of energy conservation in polysulfide respiration.,Jormakka M, Yokoyama K, Yano T, Tamakoshi M, Akimoto S, Shimamura T, Curmi P, Iwata S Nat Struct Mol Biol. 2008 Jul;15(7):730-7. Epub 2008 Jun 8. PMID:18536726^[1]

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