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- * Respiratory-chain NADH dehydrogenase 49 Kd subunit signature *
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- Respiratory-chain NADH dehydrogenase (EC 1.6.5.3) [1,2] (also known as complex
- I or NADH-ubiquinone oxidoreductase) is an oligomeric enzymatic complex
- located in the inner mitochondrial membrane which also seems to exist in
- the chloroplast and in cyanobacteria (as a NADH-plastoquinone oxidoreductase).
- Among the 25 to 30 polypeptide subunits of this bioenergetic enzyme complex
- there is one with a molecular weight of 49 Kd (in mammals), which is the third
- largest subunit of complex I and is a component of the iron-sulfur (IP)
- fragment of the enzyme. It seems to bind a 4Fe-4S iron-sulfur cluster. The 49
- Kd subunit has been found to be:
-
- - Nuclear encoded, as a precursor form with a transit peptide in mammals, and
- in Neurospora crassa.
- - Mitochondrial encoded in protozoan such as Paramecium (ORF 400), Leishmania
- and Trypanosoma (MURF 3).
- - Chloroplast encoded in various higher plants (ORF 392).
-
- The 49 Kd subunit is also highly similar to [3]:
-
- - Subunit D of Escherichia coli NADH-ubiquinone oxidoreductase (gene nuoD).
- - Subunit NQO4 of Paracoccus denitrificans NADH-ubiquinone oxidoreductase.
- - Subunit 5 of Escherichia coli formate hydrogenlyase (gene hycE).
-
- As as signature pattern we selected a highly conserved region, located in the
- N-terminal section of this subunit.
-
- -Consensus pattern: [LIVMH]-H-R-G-x-E-K-[LIVM]-x-E-x-[KRQ]
- -Sequences known to belong to this class detected by the pattern: ALL.
- -Other sequence(s) detected in SWISS-PROT: NONE.
- -Last update: June 1994 / Pattern and text revised.
-
- [ 1] Ragan C.I.
- Curr. Top. Bioenerg. 15:1-36(1987).
- [ 2] Weiss H., Friedrich T., Hofhaus G., Preis D.
- Eur. J. Biochem. 197:563-576(1991).
- [ 3] Weidner U., Geier S., Ptock A., Friedrich T., Leif H., Weiss H.
- J. Mol. Biol. 233:109-122(1993).
-