title: Altered expression of the H+ ATPase in Streptococcus faecalis membranes.
abstract: Evidence is presented that expression of the H+ ATPase in S. faecalis is influenced by the extracellular pH and K+ level during growth. Altered expression was detected by assay of F1 ATPase and electrophoretic analysis of membrane proteins. K+-limited growth caused about a 2-fold increase in the F1 ATPase. The effect of growth at pH 6, 7 and 9 was studied. Compared to cells grown at pH 7, growth at pH 6 increased the F1 ATPase about 2-fold while growth at pH 9 reduced the F1 ATPase by nearly 4-fold. The elevated F1 ATPase activity in the pH 6 cells was associated with an increase in the F1 ATPase alpha and beta subunits in the membrane while the decrease in F1 ATPase in the pH 9 cells was associated with a marked loss of the alpha subunit. It is suggested that intracellular protons may act as effectors which regulate expression of the F1F0 gene cluster at the level of translation.
mesh_terms: D004591:Electrophoresis, Polyacrylamide Gel; D013293:Enterococcus faecalis / Q000201:enzymology* / Q000254:growth & development; D005786:Gene Expression Regulation / Q000187:drug effects*; D006863:Hydrogen-Ion Concentration; D008565:Membrane Proteins / Q000096:biosynthesis; D011188:Potassium / Q000494:pharmacology*; D006180:Proton-Translocating ATPases / Q000096:biosynthesis*
chemical_list: D008565:Membrane Proteins; D006180:Proton-Translocating ATPases; D011188:Potassium