Respiratory Na+ pump and Na+-dependent energetics inVibrio alginolyticus |
| |
Authors: | Hajime Tokuda |
| |
Affiliation: | (1) Institute of Applied Microbiology, University of Tokyo, 1-1-1 Yayoi, Bunkyo, 113 Tokyo, Japan |
| |
Abstract: | The marine bacteriumVibrio alginolyticus was found to possess the respiratory Na+ pump that generates an electrochemical potential of Na+, which plays a central role in bioenergetics ofV. alginolyticus, as a direct result of respiration. Mutants defective in the Na+ pump revealed that one of the two kinds of NADH: quinone oxidoreductase requires Na+ for activity and functions as the Na+ pump. The Na+ pump composed of three subunits was purified and reconstituted into liposomes. Generation of membrane potential by the reconstituted proteoliposomes required Na+. The respiratory Na+ pump coupled to the NADH: quinone oxidoreductase was found in wide varieties of Gramnegative marine bacteria belonging to the generaAlcaligenes, Alteromonas, andVibrio, and showed a striking similarity in the mode of electron transfer and enzymic properties. Na+ extrusion seemed to be coupled to a dismutation reaction, which leads to the formation of quinol and quinone from semi-quinone radical. |
| |
Keywords: | Na+ pump NADH quinone oxidoreductase marine bacteria Na+-circulation respiration |
本文献已被 SpringerLink 等数据库收录! |
|