title: Role of the carboxyl terminal region of H(+)-ATPase (F0F1) a subunit from Escherichia coli.
abstract: The effects of amino acid substitutions in the carboxyl terminal region of the H(+)-ATPase a subunit (271 amino acid residues) of Escherichia coli were studied using a defined expression system for uncB genes coded by recombinant plasmids. The a subunits with the mutations, Tyr-263----end, Trp-231----end, Glu-219----Gln, and Arg-210----Lys (or Gln) were fully defective in ATP-dependent proton translocation, and those with Gln-252----Glu (or Leu), His-245----Glu, Pro-230----Leu, and Glu-219----His were partially defective. On the other hand, the phenotypes of the Glu-269----end, Ser-265----Ala (or end), and Tyr-263----Phe mutants were essentially similar to that of the wild-type. These results suggested that seven amino acid residues between Ser-265 and the carboxyl terminus were not required for the functional proton pathway but that all the other residues except Arg-210, Glu-219, and His-245 were required for maintaining the correct conformation of the proton pathway. The results were consistent with a report that Arg-210 is directly involved in proton translocation.
authors.affiliation: Department of Organic Chemistry and Biochemistry, Osaka University, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Eya
authors.forename: M
authors.initials: M
authors.lastname: Maeda
authors.forename: M
authors.initials: M
authors.lastname: Futai
mesh_terms: D001120:Arginine; D001483:Base Sequence; D004252:DNA Mutational Analysis; D004926:Escherichia coli / Q000201:enzymology* / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008564:Membrane Potentials; D008969:Molecular Sequence Data; D009841:Oligonucleotides / Q000737:chemistry; D010085:Oxidative Phosphorylation; D006180:Proton-Translocating ATPases / Q000502:physiology*; D013329:Structure-Activity Relationship
chemical_list: D009841:Oligonucleotides; D001120:Arginine; D006180:Proton-Translocating ATPases