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Updated: Aug 11, 2026

Visualization of ATP Synthase Dimers in Mitochondria by Electron Cryo-tomography
10:39

Visualization of ATP Synthase Dimers in Mitochondria by Electron Cryo-tomography

Published on: September 14, 2014

Topography of oligomycin sensitivity conferring protein in the mitochondrial adenosinetriphosphatase-ATP synthase

P Archinard, C Godinot, J Comte

    Biochemistry
    |June 3, 1986
    PubMed

    Insights

    Oligomycin sensitivity conferring protein (OSCP) is located on the inner face of the mitochondrial inner membrane. This ATP synthase component interacts with alpha, beta, and other subunits, suggesting a conserved structural role.

    Area of Science:

    • Biochemistry
    • Molecular Biology
    • Cell Biology

    Background:

    • The mitochondrial ATP synthase is crucial for cellular energy production.
    • Understanding the topographical organization of its subunits is key to elucidating its function.
    • Oligomycin sensitivity conferring protein (OSCP) is a component of the ATP synthase.

    Purpose of the Study:

    • To determine the topographical organization of OSCP within the mitochondrial ATP synthase complex.
    • To investigate the interactions of OSCP with other subunits of the ATP synthase.
    • To compare the organization of OSCP with homologous proteins in other organisms.

    Main Methods:

    • Immunocytochemistry using protein A-gold electron microscopy to visualize OSCP accessibility.
    • Immunotitration to quantitatively estimate OSCP.
    • Chemical cross-linking experiments with various cross-linkers (e.g., [125I]TID, dimethyl suberimidate, [35S]SNAP).
    • Identification of cross-linked products via immunocharacterization and molecular weight analysis.

    Main Results:

    • OSCP is located on the inner face of the inner mitochondrial membrane, inaccessible to hydrophobic labeling agents.
    • Cross-linking experiments revealed interactions between OSCP and the alpha- and beta-subunits of F1, as well as a 24,000 MW subunit.
    • Further cross-linking indicated OSCP's proximity to two peptides of approximately 30,000 MW.
    • A structural analogy was suggested between OSCP and the hydrophilic portion of the Escherichia coli b-subunit.

    Conclusions:

    • OSCP is situated on the matrix side of the inner mitochondrial membrane.
    • OSCP plays a role in the structural integrity and/or function of the ATP synthase by interacting with multiple subunits.
    • The findings suggest a conserved structural motif for this subunit across different species.

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