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- * Respiratory-chain NADH dehydrogenase 51 Kd subunit signatures *
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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 51 Kd (in mammals), which is the
- second largest subunit of complex I and is a component of the iron-sulfur (IP)
- fragment of the enzyme. It seems to bind to NAD, FMN, and a 2Fe2S cluster.
-
- It has been shown [3] that the 51 Kd subunit is highly similar to subunit
- alpha of the NAD-reducing hydrogenase of Alcaligenes eutrophus (EC 1.12.1.2)
- (gene hoxF) which also binds to NAD, FMN, and a 2Fe2S cluster. The
- Paracoccus denitrificans NQO1 and Escherichia coli nuoF subunits also belong
- to this family [4].
-
- The 51 Kd subunit and the bacterial hydrogenase alpha subunit contains three
- regions of sequence similarities. The first one most probably corresponds to
- the NAD-binding site, the second to the FMN-binding site, and the third one,
- which contains three cysteines, to the iron-sulfur binding region. We have
- developed signature patterns for the FMN-binding and for the 2Fe2S binding
- regions.
-
- -Consensus pattern: G-A-G-[AR]-Y-[LIVM]-C-G-[DE](2)-[STA](2)-[LI](2)-[EN]-S
- -Sequences known to belong to this class detected by the pattern: ALL.
- -Other sequence(s) detected in SWISS-PROT: NONE.
-
- -Consensus pattern: E-S-C-G-x-C-x-P-C-R-x-G
- [The three C's are putative 2Fe2S ligands]
- -Sequences known to belong to this class detected by the pattern: ALL.
- -Other sequence(s) detected in SWISS-PROT: NONE.
-
- -Last update: June 1994 / Patterns 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] Preis D., Weidner U., Conzen C., Azevedo J.E., Nehls U., Roehlen D.-A.,
- van der Pas J.C., Sackmann U., Schneider R., Werner S., Weiss H.
- Biochim. Biophys. Acta 1090:133-138(1991).
- [ 4] Weidner U., Geier S., Ptock A., Friedrich T., Leif H., Weiss H.
- J. Mol. Biol. 233:109-122(1993).
-