Article (Scientific journals)
Identification and characterization of a protozoan uncoupling protein in Acanthamoeba castellanii.
Jarmuszkiewicz, Wieslawa; Sluse-Goffart, Claudine; Hryniewiecka, L. et al.
1999In Journal of Biological Chemistry, 274 (33), p. 23198-23202
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Keywords :
Identification; characterization; protozoan; uncoupling protein; acanthamoebia castellanii
Abstract :
[en] An uncoupling protein (UCP) has been identified in mitochondria from Acanthamoeba castellanii, a nonphotosynthetic soil amoeboid protozoon that, in molecular phylogenesis, appears on a branch basal to the divergence points of plants, animals, and fungi. The existence of UCP in A. castellanii (AcUCP) has been revealed using antibodies raised against plant UCP. Its molecular mass (32,000 Da) was similar to those of plant and mammalian UCPs. The activity of AcUCP has been investigated in mitochondria depleted of free fatty acids. Additions of linoleic acid stimulated state 4 respiration and decreased transmembrane electrical potential (DeltaPsi) in a manner expected from fatty acid cycling-linked H(+) reuptake. The half-maximal stimulation by linoleic acid was reached at 8.1 +/- 0.4 microM. Bovine serum albumin (fatty acid-free), which adsorbs linoleic acid, reversed the respiratory stimulation and correspondingly restored DeltaPsi. AcUCP was only weakly inhibited by purine nucleotides like UCP in plants. A single force-flow relationship has been observed for state 4 respiration with increasing concentration of linoleic acid or of an uncoupler and for state 3 respiration with increasing concentration of oligomycin, indicating that linoleic acid has a pure protonophoric effect. The activity of AcUCP in state 3 has been evidenced by ADP/oxygen atom determination. The discovery of AcUCP indicates that UCPs emerged, as specialized proteins for H(+) cycling, early during phylogenesis before the major radiation of phenotypic diversity in eukaryotes and could occur in the whole eukaryotic world.
Disciplines :
Biochemistry, biophysics & molecular biology
Author, co-author :
Jarmuszkiewicz, Wieslawa;  Université de Liège - ULiège
Sluse-Goffart, Claudine;  Université de Liège - ULiège
Hryniewiecka, L.
Sluse, Francis ;  Université de Liège - ULiège > Département des sciences de la vie > Bioénergétique et physiologie cellulaire
Language :
English
Title :
Identification and characterization of a protozoan uncoupling protein in Acanthamoeba castellanii.
Publication date :
1999
Journal title :
Journal of Biological Chemistry
ISSN :
0021-9258
eISSN :
1083-351X
Publisher :
American Society for Biochemistry and Molecular Biology, Baltimore, United States - Maryland
Volume :
274
Issue :
33
Pages :
23198-23202
Peer reviewed :
Peer Reviewed verified by ORBi
Available on ORBi :
since 17 December 2009

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