Bogachev A V, Murtazina R A, Skulachev V P
Department of Bioenergetics, A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Russia.
J Bacteriol. 1996 Nov;178(21):6233-7. doi: 10.1128/jb.178.21.6233-6237.1996.
Anaerobically grown Escherichia coli cells were shown to acidify the reaction medium in response to oxygen or dimethyl sulfoxide (DMSO) pulses, with the H+/e- stoichiometry being close to 2.5 and 1.5, respectively. In the presence of the NADH dehydrogenase I (NDH-I) inhibitor 8-methyl-N-vanillyl-6-nonenamide (capsaicin) or in mutants lacking NDH-I, this ratio decreased to 1 for O2 and to 0 for DMSO. These data suggest that (i) the H+/e- stoichiometry for E. coli NDH-I is at least 1.5 and (ii) the DMSO reductase does not generate a proton motive force.