Structure of the F1-binding domain of the stator of bovine F1Fo-ATPase and how it binds an alpha-subunit.
The peripheral stalk of ATP synthase holds the alpha3beta3 catalytic subcomplex stationary against the torque of the rotating central stalk. In bovine mitochondria, the N-terminal domain of the oligomycin sensitivity conferral protein (OSCP-NT; residues 1-120) anchors one end of the peripheral stalk to the N-terminal tails of one or more alpha-subunits of the F1 subcomplex. Here we present the solution structure of OSCP-NT and an NMR titration study of its interaction with peptides representing N-terminal tails of F1 alpha-subunits. The structure comprises a bundle of six alpha-helices, and its interaction site contains adjoining hydrophobic surfaces of helices 1 and 5; residues in the region 1-8 of the alpha-subunit are essential for the interaction. The OSCP-NT is similar to the N-terminal domain of the delta-subunit from Escherichia coli ATP synthase (delta-NT), except that their surface charges differ (basic and acidic, respectively). As the charges of the adjacent crown regions in their alpha3beta3 complexes are similar, the OSCP-NT and delta-NT probably do not contact the crowns extensively. The N-terminal tails of alpha-subunit tails are probably alpha-helical, and so this interface, which is essential for the rotary mechanism of the enzyme, appears to consist of helix-helix interactions.
Carbajo
Rodrigo J
RJ
MRC Dunn Human Nutrition Unit, Hills Road, Cambridge CB2 2XY, UK.
Kellas
Fiona A
FA
Runswick
Michael J
MJ
Montgomery
Martin G
MG
Walker
John E
JE
Neuhaus
David
D
D000251:Adenosine Triphosphatases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002352:Carrier Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D002417:Cattle; D066298:In Vitro Techniques; D008565:Membrane Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D025261:Mitochondrial Proton-Translocating ATPases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D010446:Peptide Fragments / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017434:Protein Structure, Tertiary; D021122:Protein Subunits; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D055672:Static Electricity
D002352:Carrier Proteins; D008565:Membrane Proteins; D010446:Peptide Fragments; D021122:Protein Subunits; D011994:Recombinant Proteins; D000251:Adenosine Triphosphatases; D025261:Mitochondrial Proton-Translocating ATPases; C020439:oligomycin sensitivity-conferring protein