Article (Scientific journals)
The fully-active and structurally-stable form of the mitochondrial ATP synthase of Polytomella sp is dimeric
Villavicencio-Queijeiro, Alexa; Vazquez-Acevedo, Miriam; Cano-Estrada, Araceli et al.
2009In Journal of Bioenergetics and Biomembranes, 41 (1), p. 1-13
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Abstract :
[en] Mitochondrial F1FO-ATP synthase of chlorophycean algae is a stable dimeric complex of 1,600 kDa. It lacks the classic subunits that constitute the peripheral stator-stalk and the orthodox polypeptides involved in the dimerization of the complex. Instead, it contains nine polypeptides of unknown evolutionary origin named ASA1 to ASA9. The isolated enzyme exhibited a very low ATPase activity (0.03 Units/mg), that increased upon heat treatment, due to the release of the F-1 sector. Oligomycin was found to stabilize the dimeric structure of the enzyme, providing partial resistance to heat dissociation. Incubation in the presence of low concentrations of several non-ionic detergents increased the oligomycin-sensitive ATPase activity up to 7.0-9.0 Units/mg. Incubation with 3% (w/v) taurodeoxycholate monomerized the enzyme. The monomeric form of the enzyme exhibited diminished activity in the presence of detergents and diminished oligomycin sensitivity. Cross-linking experiments carried out with the dimeric and monomeric forms of the ATP synthase suggested the participation of the ASA6 subunit in the dimerization of the enzyme. The dimeric enzyme was more resistant to heat treatment, high hydrostatic pressures, and protease digestion than the monomeric enzyme, which was readily disrupted by these treatments. We conclude that the fully-active algal mitochondrial ATP synthase is a stable catalytically active dimer; the monomeric form is less active and less stable. Monomer-monomer interactions could be mediated by the membrane-bound subunits ASA6 and ASA9, and may be further stabilized by other polypeptides such as ASA1 and ASA5.
Disciplines :
Biochemistry, biophysics & molecular biology
Author, co-author :
Villavicencio-Queijeiro, Alexa
Vazquez-Acevedo, Miriam
Cano-Estrada, Araceli
Zarco-Zavala, Mariel
de Gomez, Marietta Tuena
Mignaco, Julio A
Freire, Monica M
Scofano, Helena M
Foguel, Debora
Cardol, Pierre  ;  Université de Liège - ULiège > Département des sciences de la vie > Génétique
Remacle, Claire  ;  Université de Liège - ULiège > Département des sciences de la vie > Génétique
Gonzalez-Halphen, Diego
Language :
English
Title :
The fully-active and structurally-stable form of the mitochondrial ATP synthase of Polytomella sp is dimeric
Publication date :
2009
Journal title :
Journal of Bioenergetics and Biomembranes
ISSN :
0145-479X
eISSN :
1573-6881
Publisher :
Kluwer Academic/Plenum Publishers, New York, United States - New York
Volume :
41
Issue :
1
Pages :
1-13
Peer reviewed :
Peer Reviewed verified by ORBi
Available on ORBi :
since 28 February 2010

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