Na+-driven ATP synthesis of a psychrophilic marine bacterium,Vibriosp. strain ABE-1

Abstract

Abstract In vivo ATP synthesis of a psychrophilic marine bacterium, Vibrio sp. strain ABE-1, derived from endogenous respiration, was examined. ATP was synthesized at both pH 6.5 and 8.5 after the start of the endogenous respiration by supplying O 2 to the anaerobic cell suspension. The ATP synthesis at pH 6.5, but not at pH 8.5, was completely inhibited by a H + conductor, carbonylcyanide m -chlorophenylhydrazone (CCCP). The CCCP-resistant ATP synthesis at pH 8.5 was strongly inhibited by an inhibitor of the respiration-dependent primary Na + pump, 2- n -heptyl-4-hydroxyquinoline N -oxide, and essentially required Na + . These results show that this bacterium synthesizes ATP at pH 6.5 by electrochemical potentials across the membrane Δ ≈ μ H + , whereas at pH 8.5 by Δ ≈ μ Na + but not Δ ≈ μ H + .