RRC ID 1889
Author Goepfert S, Hiltunen JK, Poirier Y.
Title Identification and functional characterization of a monofunctional peroxisomal enoyl-CoA hydratase 2 that participates in the degradation of even cis-unsaturated fatty acids in Arabidopsis thaliana.
Journal J Biol Chem
Abstract A gene, named AtECH2, has been identified in Arabidopsis thaliana to encode a monofunctional peroxisomal enoyl-CoA hydratase 2. Homologues of AtECH2 are present in several angiosperms belonging to the Monocotyledon and Dicotyledon classes, as well as in a gymnosperm. In vitro enzyme assays demonstrated that AtECH2 catalyzed the reversible conversion of 2E-enoyl-CoA to 3R-hydroxyacyl-CoA. AtECH2 was also demonstrated to have enoyl-CoA hydratase 2 activity in an in vivo assay relying on the synthesis of polyhydroxyalkanoate from the polymerization of 3R-hydroxyacyl-CoA in the peroxisomes of Saccharomyces cerevisiae. AtECH2 contained a peroxisome targeting signal at the C-terminal end, was addressed to the peroxisome in S. cerevisiae, and a fusion protein between AtECH2 and a fluorescent protein was targeted to peroxisomes in onion cells. AtECH2 gene expression was strongest in tissues with high beta-oxidation activity, such as germinating seedlings and senescing leaves. The contribution of AtECH2 to the degradation of unsaturated fatty acids was assessed by analyzing the carbon flux through the beta-oxidation cycle in plants that synthesize peroxisomal polyhydroxyalkanoate and that were over- or underexpressing the AtECH2 gene. These studies revealed that AtECH2 participates in vivo to the conversion of the intermediate 3R-hydroxyacyl-CoA, generated by the metabolism of fatty acids with a cis (Z)-unsaturated bond on an even-numbered carbon, to the 2E-enoyl-CoA for further degradation through the core beta-oxidation cycle.
Volume 281(47)
Pages 35894-903
Published 2006-11-24
DOI 10.1074/jbc.M606383200
PII M606383200
PMID 16982622
MeSH Amino Acid Sequence Arabidopsis / enzymology* Arabidopsis / genetics Arabidopsis Proteins / chemistry* Arabidopsis Proteins / genetics* Carbon / chemistry Catalysis Enoyl-CoA Hydratase / chemistry* Enoyl-CoA Hydratase / genetics Fatty Acids / chemistry Fatty Acids, Unsaturated / chemistry* Molecular Sequence Data Onions Oxygen / chemistry Peroxisomes / chemistry Peroxisomes / enzymology* Plant Proteins / chemistry Recombinant Fusion Proteins / chemistry Saccharomyces cerevisiae / metabolism Sequence Homology, Amino Acid
IF 4.106
Times Cited 20
Arabidopsis / Cultured plant cells, genes pda03253