Δ3,52,4-dienoyl-CoA isomerase from rat liver. Molecular characterization

S. A. Filppula, A. I. Yagi, S. H. Kilpeläinen, D. Novikov, D. R. FitzPatrick, M. Vihinen, D. Valle, J. K. Hiltunen

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45 Scopus citations

Abstract

rECH1, a recently identified rat cDNA (FitzPatrick, D. R., Germain-Lee, E., and Valle, D. (1995) Genomics 27, 457-466) encodes a polypeptide belonging to the hydratase/isomerase superfamily. We modeled the structure of rECH1 based on rat mitochondrial 2-enoyl-CoA hydratase 1. The model predicts that rECH1p has the hydratase fold in the core domain and two domains for interaction with other subunits. When we incubated 3,5,8,11,14- eicosapentaenoyl-CoA with purified rECH1p, the spectral data suggested a switching of the double bonds from the Δ35 to the Δ24 positions. This was confirmed by demonstrating that the product was a valid substrate for 2,4-dienoyl-CoA reductase. These results indicate that rECH1p is Δ3,52,4-dienoyl-CoA isomerase. Subcellular fractionation and immunoelectron microscopy using antibodies to a synthetic polypeptide derived from the C terminus of rECH1p showed that rECH1p is located in the matrix of both mitochondria and peroxisomes in rat liver. Consistent with these observations, the 36,000-Da rECH1p has a potential N-terminal mitochondrial targeting signal as well as a C-terminal peroxisomal targeting signal type 1. Transport of the protein into the mitochondria with cleavage of the targeting signal results in a mature mitochondrial form with a molecular mass of 32,000 Da; transport to peroxisomes yields a protein of 36,000 Da.

Original languageEnglish (US)
Pages (from-to)349-355
Number of pages7
JournalJournal of Biological Chemistry
Volume273
Issue number1
DOIs
StatePublished - Jan 2 1998

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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