title: Oxidative phosphorylation by mutant Escherichia coli membranes with impaired proton permeability.
abstract: The effect on the function of the Escherichia coli F1F0-ATPase of the substitution of leucine-31 by phenylalanine in the c-subunit of the enzyme was examined. The assembly of the mutant c-subunit requires an increased gene dosage [Jans, Fimmel, Langman, James, Downie, Senior, Ash, Gibson & Cox (1983) Biochem. J. 211, 717-726], and this was achieved by incorporation of the uncE408 or uncE463 alleles on to F-plasmids or multicopy plasmids. Membranes from strains carrying either the uncE463 or uncE408 alleles on F-plasmids or multicopy plasmids were capable of carrying out oxidative phosphorylation. In particular, membranes from strain AN1928 (pAN162, uncE463) gave phosphorylation rates and P/O ratios equal to or greater than those obtained for the control strain AN1460 (pAN45, unc+). However, the mutant membranes, on removal of the F1-ATPase, appeared to be proton-impermeable. The ATPase activity of the mutant membranes was also resistant to the inhibitor dicyclohexylcarbodi-imide.
mesh_terms: D000251:Adenosine Triphosphatases / Q000037:antagonists & inhibitors; D002462:Cell Membrane / Q000378:metabolism; D002463:Cell Membrane Permeability / Q000187:drug effects; D004024:Dicyclohexylcarbodiimide / Q000494:pharmacology; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D007930:Leucine / Q000378:metabolism; D009154:Mutation; D009876:Operon; D010085:Oxidative Phosphorylation / Q000187:drug effects; D010649:Phenylalanine / Q000378:metabolism; D011522:Protons; D013050:Spectrometry, Fluorescence
chemical_list: D011522:Protons; D010649:Phenylalanine; D004024:Dicyclohexylcarbodiimide; D000251:Adenosine Triphosphatases; D007930:Leucine