Characterization of domain interfaces in monomeric and dimeric ATP synthase.
We disassembled monomeric and dimeric yeast ATP synthase under mild conditions to identify labile proteins and transiently stable subcomplexes that had not been observed before. Specific removal of subunits alpha, beta, oligomycin sensitivity conferring protein (OSCP), and h disrupted the ATP synthase at the gamma-alpha(3)beta(3) rotor-stator interface. Loss of two F(1)-parts from dimeric ATP synthase led to the isolation of a dimeric subcomplex containing membrane and peripheral stalk proteins thus identifying the membrane/peripheral stalk sectors immediately as the dimerizing parts of ATP synthase. Almost all subunit a was found associated with a ring of 10 c-subunits in two-dimensional blue native/SDS gels. We therefore postulate that c10a1-complex is a stable structure in resting ATP synthase until the entry of protons induces a breaking of interactions and stepwise rotation of the c-ring relative to the a-subunit in the catalytic mechanism. Dimeric subunit a was identified in SDS gels in association with two c10-rings suggesting that a c10a2c10-complex may constitute an important part of the monomer-monomer interface in dimeric ATP synthase that seems to be further tightened by subunits b, i, e, g, and h. In contrast to the monomer-monomer interface, the interface between dimers in higher oligomeric structures remains largely unknown. However, we could show that the natural inhibitor protein Inh1 is not required for oligomerization.
Wittig
Ilka
I
Zentrum der Biologischen Chemie, Molekulare Bioenergetik, Cluster of Excellence "Macromolecular Complexes", Johann Wolfgang Goethe-Universität Frankfurt, D-60590 Frankfurt, Germany.
Velours
Jean
J
Stuart
Rosemary
R
Schägger
Hermann
H
D048868:Adaptor Proteins, Signal Transducing; D000251:Adenosine Triphosphatases / Q000737:chemistry / Q000235:genetics; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics; D019281:Dimerization; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics; D024101:Mitochondrial Proteins / Q000737:chemistry / Q000235:genetics; D025261:Mitochondrial Proton-Translocating ATPases / Q000737:chemistry* / Q000235:genetics; D009097:Multienzyme Complexes / Q000737:chemistry* / Q000235:genetics; D009154:Mutation; D017434:Protein Structure, Tertiary; D021122:Protein Subunits / Q000737:chemistry / Q000235:genetics; D011506:Proteins / Q000737:chemistry / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry* / Q000235:genetics; D000097795:ATPase Inhibitory Protein
D048868:Adaptor Proteins, Signal Transducing; D000251:Adenosine Triphosphatases; D002352:Carrier Proteins; D008565:Membrane Proteins; D024101:Mitochondrial Proteins; D025261:Mitochondrial Proton-Translocating ATPases; D009097:Multienzyme Complexes; D021122:Protein Subunits; D011506:Proteins; D029701:Saccharomyces cerevisiae Proteins; D000097795:ATPase Inhibitory Protein; C469352:STF1 protein, S cerevisiae; C469353:STF2 protein, S cerevisiae; C020439:oligomycin sensitivity-conferring protein