biostudies-literatureGrigoryan LHigher Education and Science Committee of the Ministry of Education Science Culture and Sports of the Republic of ArmeniaMinistry of Education and Science100225https://www.ebi.ac.uk/biostudies/studies/S-EPMC12396580biostudies-literatureUnknown5(3)Escherichia coli translocates formate/formic acid bidirectionally across the cytoplasmic membrane by the FocA/FocB formate channels during fermentation. Depending on the pH and whether formate is supplied exogenously or generated internally, the mechanisms of translocation differ. This study elucidates the role of these channels in dependence on FOF1 ATPase activity in stationary phase cells after cultivation by mixed-carbon fermentation at pH 7.5. In cells cultivated with glucose plus glycerol, exogenously added formate increased the N,N'-dicyclohexylcarbodiimide (DCCD)-sensitive (FOF1 ATPase-dependent) proton flux in single or double foc mutants. Moreover, exogenously supplied formate also increased the DCCD-sensitive potassium flux, but only iBiophysical reportsEscherichia coli FocA/B-dependent H+ and K+ fluxes: Influence of exogenous versus endogenous formate.PMC1239658021AG-1F043Poladyan AVassilian ASawers GTrchounian KGrigoryan LBabayan AfalseEscherichia coli FocA/B-dependent H+ and K+ fluxes: Influence of exogenous versus endogenous formate.Escherichia coli translocates formate/formic acid bidirectionally across the cytoplasmic membrane by the FocA/FocB formate channels during fermentation. Depending on the pH and whether formate is supplied exogenously or generated internally, the mechanisms of translocation differ. This study elucidates the role of these channels in dependence on FOF1 ATPase activity in stationary phase cells after cultivation by mixed-carbon fermentation at pH 7.5. In cells cultivated with glucose plus glycerol, exogenously added formate increased the N,N'-dicyclohexylcarbodiimide (DCCD)-sensitive (FOF1 ATPase-dependent) proton flux in single or double foc mutants. Moreover, exogenously supplied formate also increased the DCCD-sensitive potassium flux, but only i2025-01-01T00:00:00Z2025 Aug2026-04-08T11:11:31.041Z2026-04-08T01:50:04.153ZS-EPMC123965804078458310.1016/j.bpr.2025.100225