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The role of the amino-terminal beta-barrel domain of the alpha and beta subunits in the yeast F1-ATPase.

The crystal structure of mitochondrial F1-ATPase indicates that the alpha and beta subunits fold into a structure defined by three domains: the top beta-barrel domain, the middle nucleotide-binding domain, and the C-terminal alpha-helix bundle domain (Abrahams et al., 1994); Bianchet et al., 1998). The beta-barrel domains of the alpha and beta subunits form a crown structure at the top of F1, which was suggested to stabilize it (Abrahams et al. 1994). In this study, the role of the beta-barrel domain in the alpha and beta subunits of the yeast Saccharomyces cerevisiae F1, with regard to its folding and assembly, was investigated. The beta-barrel domains of yeast F1alpha and beta subunits were expressed individually and together in Escherichia coli. When expressed separately, the beta-barrel domain of the beta subunit formed a large aggregate structure, while the domain of the alpha subunit was predominately a monomer or dimer. However, coexpression of the beta-barrel domain of alpha subunit with the beta-barrel domain of beta subunit, greatly reduced the aggregation of the beta subunit domain. Furthermore, the two domains copurified in complexes with the major portion of the complex found in a small molecular weight form. These results indicate that the beta-barrel domain of the alpha and beta subunits interact specifically with each other and that these interactions prevent the aggregation of the beta-barrel domain of the beta subunit. These results mimic in vivo results and suggest that the interactions of the beta-barrel domains may be critical during the folding and assembly of F1.

Pubmed ID: 10449236

Authors

  • Yao B
  • Mueller DM

Journal

Journal of bioenergetics and biomembranes

Publication Data

April 14, 1999

Associated Grants

  • Agency: NIGMS NIH HHS, Id: GM44412

Mesh Terms

  • Amino Acid Sequence
  • Animals
  • Cattle
  • Cloning, Molecular
  • Escherichia coli
  • Macromolecular Substances
  • Mitochondria
  • Molecular Sequence Data
  • Molecular Weight
  • Peptide Fragments
  • Polymerase Chain Reaction
  • Protein Structure, Secondary
  • Proton-Translocating ATPases
  • Recombinant Proteins
  • Saccharomyces cerevisiae
  • Sequence Alignment
  • Sequence Homology, Amino Acid