1. The role of the ESSS protein in the assembly of a functional and stable mammalian mitochondrial complex I (NADH-ubiquinone oxidoreductase).
- Author
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Potluri, Prasanth, Yadava, Nagendra, and Scheffler, Immo E.
- Subjects
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PROTEINS , *DNA , *ELECTROPHORESIS , *POLAROGRAPHY , *HEMAGGLUTININ , *EPITOPES - Abstract
The ESSS protein is a recently identified subunit of mammalian mitochondrial complex I. It is a relatively small integral membrane protein (122 amino acids) found in the β-subcomplex. Genomic sequence database searches reveal its localization to the X-chromosome in humans and mouse. The ESSS cDNA from Chinese hamster cells was cloned and shown to complement one complementation group of our previously described mutants with a proposed X-linkage. Sequence analyses of the ESSS cDNA in these mutants revealed chain termination mutations. In two of these mutants the protein is truncated at the C-terminus of the targeting sequence; the mutants are null mutants for the ESSS subunit. There is no detectable complex I assembly and activity in the absence of the ESSS subunit as revealed by blue native polyacrylamide gel electrophoresis (BN/PAGE) analysis and polarography. Complex I activity can be restored with ESSS subunits tagged with either hemagglutinin (HA) or hexahistidine (His6) epitopes at the C-terminus. Although, the accumulation of ESSS-HA is not dependent upon the presence of mtDNA-encoded subunits (ND1-6,4 L), it is incorporated into complex I only in presence of compatible complex I subunits from the same species. [ABSTRACT FROM AUTHOR]
- Published
- 2004
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