Definition of the nuclear encoded protein composition of bovine heart mitochondrial complex I. Identification of two new subunits

Mitochondrial NADH:ubiquinone oxidoreductase (complex I) from bovine heart is a complicated multisubunit, membrane-bound assembly. Seven subunits are encoded by mitochondrial DNA, and the sequences of 36 nuclear encoded subunits have been described. The subunits of complex I and two subcomplexes (Ia...

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Bibliographic Details
Published in:The Journal of biological chemistry 2002-12, Vol.277 (52), p.50311-50317
Main Authors: Carroll, Joe, Shannon, Richard J, Fearnley, Ian M, Walker, John E, Hirst, Judy
Format: Article
Language:English
Subjects:
Amino Acid Sequence
Animals
Base Sequence
Cattle
Cell Nucleus - genetics
Chromatography, High Pressure Liquid
Electron Transport Complex I
Mass Spectrometry
Mitochondria, Heart - enzymology
Molecular Sequence Data
NADH, NADPH Oxidoreductases - chemistry
NADH, NADPH Oxidoreductases - genetics
NADH, NADPH Oxidoreductases - metabolism
Neurospora crassa - enzymology
Protein Subunits
Protein Transport
Sequence Alignment
Sequence Homology, Amino Acid
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Summary:Mitochondrial NADH:ubiquinone oxidoreductase (complex I) from bovine heart is a complicated multisubunit, membrane-bound assembly. Seven subunits are encoded by mitochondrial DNA, and the sequences of 36 nuclear encoded subunits have been described. The subunits of complex I and two subcomplexes (Ialpha and Ibeta) were resolved on one- and two-dimensional gels and by reverse-phase high performance liquid chromatography. Mass spectrometric analysis revealed two previously unknown subunits in complex I, named B14.7 and ESSS, one in each subcomplex. Coding sequences for each protein were identified in data bases and were confirmed by cDNA cloning and sequencing. Subunit B14.7 has an acetylated N terminus, no presequence, and contains four potential transmembrane helices. It is homologous to subunit 21.3b from complex I in Neurospora crassa and is related to Tim17, Tim22, and Tim23, which are involved in protein translocation across the inner membrane. Subunit ESSS has a cleaved mitochondrial import sequence and one potential transmembrane helix. A total of 45 different subunits of bovine complex I have now been characterized.
ISSN:0021-9258
DOI:10.1074/jbc.M209166200