Phosphoenolpyruvate:glycose phosphotransferase system in species of Vibrio, a widely distributed marine bacterial genus

Abstract

The genus Vibrio is one of the most common and widely distributed groups of marine bacteria. Studies on the physiology of marine Vibrio species were initiated by examining 15 species for the bacterial phosphoenolpyruvate:glycose phosphotransferase system (PTS). All species tested contained a PTS analogous to the glucose-specific (IIGlc) system in enteric bacteria. Crude extracts of the cells showed immunological cross-reactivity with antibodies to enzyme I, HPr, and IIIGlc from Salmonella typhimurium when assayed by the rocket-line method. Toluene-permeabilized cells of 11 species were tested and were active in phosphorylating methyl alpha-D-glucoside with phosphoenolpyruvate but not ATP as the phosphoryl donor. Membranes from 10 species were assayed, and they phosphorylated methyl alpha-D-glucoside when supplemented with a phospho-IIIGlc-generating system composed of homogeneous proteins from enteric bacteria. Toluene-permeabilized cells and membranes of seven species were assayed, as were phosphorylated fructose and 2-deoxyglucose. IIIGlc was isolated from Vibrio fluvialis and was active in phosphorylating methyl alpha-D-glucoside when supplemented with a phospho-HPr-generating system composed of homogeneous proteins from Escherichia coli and membranes from either E. coli or V. fluvialis. These results show that the bacterial PTS is widely distributed in the marine environment and that it is likely to have a significant role in marine bacterial physiology and in the marine ecosystem.