PROSITE documentation PDOC00420
ATP synthase a subunit signature


ATP synthase (proton-translocating ATPase) (EC [1,2] is a component of the cytoplasmic membrane of eubacteria, the inner membrane of mitochondria, and the thylakoid membrane of chloroplasts. The ATPase complex is composed of an oligomeric transmembrane sector, called CF(0), which acts as a proton channel, and a catalytic core, termed coupling factor CF(1).

The CF(0) a subunit, also called protein 6, is a key component of the proton channel; it may play a direct role in translocating protons across the membrane. It is a highly hydrophobic protein that has been predicted to contain 8 transmembrane regions [3].

Sequence comparison of a subunits from all available sources reveals very few conserved regions. The best conserved region is located in what is predicted to be the fifth transmembrane domain. This region contains three perfectly conserved residues: an arginine, a leucine and an asparagine. Mutagenesis experiments carried out in Escherichia coli [4] have shown that the arginine is necessary for proton translocation and that its replacement by another amino acid results in loss of ATPase activity. We selected this region as a signature pattern.

Last update:

December 2004 / Pattern and text revised.


Technical section

PROSITE method (with tools and information) covered by this documentation:

ATPASE_A, PS00449; ATP synthase a subunit signature  (PATTERN)


1AuthorsFutai M. Noumi T. Maeda M.
TitleATP synthase (H+-ATPase): results by combined biochemical and molecular biological approaches.
SourceAnnu. Rev. Biochem. 58:111-136(1989).
PubMed ID2528322

2AuthorsSenior A.E.
TitleATP synthesis by oxidative phosphorylation.
SourcePhysiol. Rev. 68:177-231(1988).
PubMed ID2892214

3AuthorsLewis M.J. Chang J.A. Simoni R.D.
TitleA topological analysis of subunit alpha from Escherichia coli F1F0-ATP synthase predicts eight transmembrane segments.
SourceJ. Biol. Chem. 265:10541-10550(1990).
PubMed ID2162353

4AuthorsCain B.D. Simoni R.D.
TitleProton translocation by the F1F0ATPase of Escherichia coli. Mutagenic analysis of the a subunit.
SourceJ. Biol. Chem. 264:3292-3300(1989).
PubMed ID2536742

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