title: Role of the b subunit of the Escherichia coli proton-translocating ATPase. A mutagenic analysis.
abstract: A plasmid that carries the uncF gene of Escherichia coli, which codes for the b subunit of the proton-translocating ATPase (F1F0), was mutagenized with hydroxylamine and ethyl methanesulfonate. Mutated plasmids were characterized by complementation analysis and by in vitro transcription/translation. Eleven of the plasmids mutated specifically in uncF were studied in detail: the nucleotide sequences of their uncF genes were determined and their effects on the F1F0 were measured. The results suggest that a C-terminal portion of the b subunit that involves the glycine residue at position 131, is required for the formation of a functional proton pore as well as for the binding of F1 to F0. A mutation in the N-terminal portion of the b subunit, in the glycine residue at position 9, also prevented the formation of a functional proton pore, but had only a small effect on the binding of F1 to F0.
authors.forename: A C
authors.initials: AC
authors.lastname: Porter
authors.forename: C
authors.initials: C
authors.lastname: Kumamoto
authors.forename: K
authors.initials: K
authors.lastname: Aldape
authors.forename: R D
authors.initials: RD
authors.lastname: Simoni
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D046911:Macromolecular Substances; D010957:Plasmids; D006180:Proton-Translocating ATPases / Q000235:genetics / Q000378:metabolism*; D013050:Spectrometry, Fluorescence
chemical_list: D046911:Macromolecular Substances; D006180:Proton-Translocating ATPases