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- ************************************
- * ATP synthase c subunit signature *
- ************************************
-
- ATP synthase (proton-translocating ATPase) (EC 3.6.1.34) [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) c subunit (also called protein 9, proteolipid, or subunit III) [3,4]
- is a highly hydrophobic protein of about 8 Kd which has been implicated in the
- proton-conducting activity of ATPase. Structurally subunit c consist of two
- long terminal hydrophobic regions, which probably span the membrane, and a
- central hydrophilic region. N,N'-dicyclohexylcarbodiimide (DCCD) can bind
- covalently to subunit c and thereby abolish the ATPase activity. DCCD binds to
- a specific glutamate or aspartate residue which is located in the middle of
- the second hydrophobic region near the C-terminus of the protein.
-
- We derived a signature pattern which includes the DCCD-binding residue.
-
- -Consensus pattern: [GSTA]-R-[NQ]-P-x(10)-[LIVMFYW](2)-x(3)-[LIVMFYW]-x-[DE]
- [D or E binds DCCD]
- -Sequences known to belong to this class detected by the pattern: ALL, except
- for sunflower mitochondrial encoded subunit C which has Trp instead of Arg in
- position 2 of the pattern.
- -Other sequence(s) detected in SWISS-PROT: vaccinia virus protein E5.
-
- -Note: the proteolipid subunit of the vacuolar ATPase, a 16 Kd protein, which
- also binds DCCD, is evolutionary related to subunit c and has arisen by the
- duplication of a subunit c type domain. This protein is however too divergent
- to be detected by this pattern.
-
- -Expert(s) to contact by email: Recipon H.
- recipon@ncbi.nlm.nih.gov
-
- -Last update: December 1992 / Text revised.
-
- [ 1] Futai M., Noumi T., Maeda M.
- Annu. Rev. Biochem. 58:111-136(1989).
- [ 2] Senior A.E.
- Physiol. Rev. 68:177-231(1988).
- [ 3] Ivaschenko A.T., Karpenyuk T.A., Ponomarenko S.V.
- Biokhimiya 56:406-419(1991).
- [ 4] Recipon H., Perasso R., Adoutte A., Quetier F.
- J. Mol. Evol. 34:292-303(1992).
-