Complementation between uncF alleles affecting assembly of the F1F0-ATPase complex of Escherichia coli.

AUTOR(ES)

Jans, D A

RESUMO

A mutant affected in the b subunit (coded by the uncF gene) of the F1F0-ATPase in Escherichia coli was isolated by a localized mutagenesis procedure in which a plasmid carrying the unc genes was mutagenized in vivo. The biochemical properties of cells carrying the uncF515 allele were examined in a strain carrying the allele on a multicopy plasmid and a mutator-induced polar unc mutation on the chromosome. The strain carrying the mutant unc allele was uncoupled with respect to oxidative phosphorylation. Membrane-bound ATPase activity was very low or absent, and membranes were somewhat proton permeable. It was concluded that the F0 sector was assembled. Determination of the DNA sequence of the uncF515 allele showed it differed from wild type in that a G----A substitution occurred at position 392, resulting in glycine being replaced by aspartate at position 131. Genetic complementation tests indicated that the uncF515 allele complemented the uncF476 allele (Gly 9----Asp). Two-dimensional gel electrophoresis of membrane preparations indicated that the uncF515 and uncF476 alleles interrupted assembly of the F1F0-ATPase at different stages.

Documentos Relacionados

• Altered translation of the uncC gene coding for the epsilon subunit of the F1F0-ATPase of Escherichia coli.
• An acidic or basic amino acid at position 26 of the b subunit of Escherichia coli F1F0-ATPase impairs membrane proton permeability: suppression of the uncF469 nonsense mutation.
• Analysis of F1F0-ATPase from Helicobacter pylori.
• Effect of the delta subunit on assembly and proton permeability of the F0 proton channel of Escherichia coli F1F0 ATPase.
• Mutations in the delta subunit influence the assembly of F1F0 ATP synthase in Escherichia coli.