β-γ Subunit interaction is required for catalysis by H+-ATPase (ATP synthase). β subunit amino acid replacements suppress a γ subunit mutation having a long unrelated carboxyl terminus

C. Jeanteur-De Beukelaer, H. Omote, A. Iwamoto-Kihara, M. Maeda, M. Futai

Research output: Contribution to journalArticle

25 Citations (Scopus)

Abstract

The mechanisms of energy coupling and catalytic cooperativity are not yet understood for H+-ATPase (ATP synthase). An Escherichia coli γ subunit frameshift mutant (downstream of Thr-γ277) could not grow by oxidative phosphorylation because both mechanisms were defective (Iwamoto, A., Miki, J., Maeda, M., and Futai, M. (1990) J. Biol. Chem. 265, 5043-5048). The defect(s) of the γ frameshift was obvious, because the mutant subunit had a carboxyl terminus comprising 16 residues different from those in the wild type. However, in this study, we surprisingly found that an Arg-β52 → Cys or Gly-β150 → Asp replacement could suppress the deleterious effects of the γ frameshift. The membranes of the two mutants (γ frameshift/Cys-β52 with or without a third mutation, Val-β77 → Ala) exhibited increased oxidative phosphorylation, together with 70-100% of the wild type ATPase activity. Similarly, the γ frameshift/Asp-β150 mutant could grow by oxidative phosphorylation, although this mutant had low membrane ATPase activity. These results suggest that the β subunit mutation suppressed the defects of catalytic cooperativity and/or energy coupling in the γ mutant, consistent with the notion that conformational transmission between the two subunits is pertinent for this enzyme.

Original languageEnglish
Pages (from-to)22850-22854
Number of pages5
JournalJournal of Biological Chemistry
Volume270
Issue number39
DOIs
Publication statusPublished - Jan 1 1995
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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