Reference |
| PMID | Title & Author | Abstract | Year |
0 | 11856339 | The function of methyl-menaquinone-6 and polysulfide reductase membrane anchor (PsrC) in polysulfide respiration of Wolinella succinogenes.Wiebke Dietrich , Oliver Klimmek | Wolinella succinogenes grows by oxidative phosphorylation with polysulfide as terminal electron acceptor and either H2 or formate as electron donor (polysulfide respiration). The function of the respiratory chains catalyzing these reactions was investigated. Proteoliposomes containing polysulfide reductase (Psr) and either hydrogenase or formate dehydrogenase isolated from the membrane fraction of Wolinella succinogenes catalyzed polysulfide respiration, provided that methyl-menaquinone-6 isolated from W. succinogenes was also present. The specific activities of electron transport were commensurate with those of the bacterial membrane fraction. Using site-directed mutagenesis, certain residues were substituted in PsrC, the membrane anchor of polysulfide reductase. Replacement of Y23, D76, Y159, D218, E225 or R305 caused nearly full inhibition of polysulfide respiration without affecting the activity of Psr, which was still bound to the membrane. These residues are predicted to be located in hydrophobic helices of PsrC, or next to them. Substitution of 13 other residues of PsrC either caused partial inhibition ofblankpolysulfide respiration or had no effect. The function of methyl-menaquinone-6, which is thought to be bound to PsrC, is discussed. | 2002 |
1 | 18536726 | Molecular mechanism of energy conservation in polysulfide respiration.Mika Jormakka , Ken Yokoyama, Takahiro Yano, Masatada Tamakoshi, Satoru Akimoto, Tatsuro Shimamura, Paul Curmi, So Iwata | 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. | 2008 |
Krafft T , Gross R , Achim Kröger. The Function of Wolinella succinogenes psr Genes in Electron Transport with Polysulphide as the Terminal Electron Acceptor[J]. European Journal of Biochemistry, 1995, 230.
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