title: Properties of membranes from mutant strains of Escherichia coli in which the beta-subunit of the adenosine triphosphatase is abnormal.
abstract: Five uncoupled mutant strains of Escherichia coli carrying mutations in the uncD gene have been studied. In each of these mutant strains the beta-subunit of the F1 portion of the membrane-bound adenosine triphosphatase is abnormal. In one of the mutant strains (carrying the uncD12 allele) in F1-ATPase aggregate was formed which was purified and found to have low ATPase activity. ATPase activity was absent in the other four strains and the abnormal beta-subunits were tightly bound to the membranes. However, membranes from these strains exhibited various proton permeabilities as indicated by NADH-dependent atebrin-fluorescence quenching and bound different amounts of normal F1-ATPase. The amounts of reconstitution of energy-linked reactions after the addition of normal F1-ATPase also varied depending on the mutant allele. It is apparent that considerable phenotypic variations can occur between strains carrying mutations in the same unc gene.
mesh_terms: D000251:Adenosine Triphosphatases / Q000235:genetics* / Q000302:isolation & purification; D000483:Alleles; D002462:Cell Membrane / Q000201:enzymology; D055598:Chemical Phenomena; D002621:Chemistry; D004586:Electrophoresis; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics*; D009154:Mutation; D011485:Protein Binding
chemical_list: D000251:Adenosine Triphosphatases