A common ancestor for a subunit in the mitochondrial
proton-translocating NADH:ubiquinone oxidoreductase (complex I) and
short-chain dehydrogenases/reductases
M. E. Baker, W. N. Grundy, C. P. Elkan
Cellular and Molecular Life Sciences 55(3):450-455,
1999
Abstract
The proton-translocating NADH:ubiquinone oxidoreductase or complex I
is located in the inner membranes of mitochondria, where it catalyzes
the transfer of electrons from NADH to ubiquinone. Here we report that
one of the subunits in complex I is homologous to short-chain
dehydrogenases and reductases, a family of enzymes with diverse
activities that include metabolizing steroids, prostaglandins and
nucleotide sugars. We discovered that a subunit of complex I in human,
cow, Neurospora crassa and Aquifex aeolius is homologous
to nucleotide-sugar epimerases and hydroxysteroid dehydrogenases while
seeking distant homologs of these enzymes with a hidden Markov
model-based search of Genpept. This homology allows us to use
information from the solved three-dimensional structures of
nucleotide-sugar epimerases and hydroxysteroid dehydrogenases and our
motif analysis of these enzymes to predict functional domains on their
homologs in complex I.
CMLS version of the article
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