DsrMKJOP is the terminal reductase complex in anaerobic sulfate respiration

• 成果类型: Article
• 署名作者: Barbosa, Ana C. C.; Venceslau, Sofia S.; Pereira, Ines A. C.
• 署名单位: Universidade Nova de Lisboa
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-11410
• DOI: 10.1073/pnas.2313650121
• 发表日期: 2024-02-06
• 关键词: heterodisulfide reductase; allochromatium-vinosum; electron-transfer; 4fe-4s cluster; active-site; vulgaris hildenborough; transmembrane complex; sulfite reductase; sulfur; protein

摘要

Microbial dissimilatory sulfate reduction (DSR) is a key process in the Earth biogeochemical sulfur cycle. In spite of its importance to the sulfur and carbon cycles, industrial processes, and human health, it is still not clear how reduction of sulfate to sulfide is coupled to energy conservation. A central step in the pathway is the reduction of sulfite by the DsrAB dissimilatory sulfite reductase, which leads to the production of a DsrC- trisulfide. A membrane - bound complex, DsrMKJOP, is present in most organisms that have DsrAB and DsrC, and its involvement in energy conservation has been inferred from sequence analysis, but its precise function was so far not determined. Here, we present studies revealing that the DsrMKJOP complex of the sulfate reducer Archaeoglobus fulgidusworks as a menadiol:DsrC- trisulfide oxidoreductase. Our results reveal a close interaction between the DsrC- trisulfide and the DsrMKJOP complex and show that electrons from the quinone pool reduce consecutively the DsrM hemes b, the DsrK noncubane [4Fe- 4S]3+/2+ catalytic center, and finally the DsrC- trisulfide with concomitant release of sulfide. These results clarify the role of this widespread respiratory membrane complex and support the suggestion that DsrMKJOP contributes to energy conservation upon reduction of the DsrC- trisulfide in the last step of DSR.