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- * Respiratory-chain NADH dehydrogenase 75 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 75 Kd (in mammals), which is the
- largest subunit of complex I and is a component of the iron-sulfur (IP)
- fragment of the enzyme. It seems to bind to two 4Fe-4S clusters (called N-3
- and N-4).
-
- It has been shown [3] that the 75 Kd subunit is highly similar to subunit
- gamma of the NAD-reducing hydrogenase of Alcaligenes eutrophus (EC 1.12.1.2)
- (gene hoxU) which also binds two 4Fe-4S clusters. The Paracoccus
- denitrificans NQO3 and Escherichia coli nuoG subunits also belong to this
- family [4].
-
- The 75 Kd subunit and the bacterial hydrogenase gamma subunit contains three
- conserved clusters of cysteine residues which are most probably involved in
- the binding of the iron-sulfur clusters. We have developed signature patterns
- for these three regions.
-
- -Consensus pattern: P-x(2)-C-[YW]-x(7)-G-x-C-R-x-C
- [The three C's are putative 4Fe4S ligands]
- -Sequences known to belong to this class detected by the pattern: ALL.
- -Other sequence(s) detected in SWISS-PROT: NONE.
-
- -Consensus pattern: C-P-x-C-[DE]-x-[GS](2)-x-C-x-L-Q
- [The three C's are putative 4Fe4S ligands]
- -Sequences known to belong to this class detected by the pattern: ALL.
- -Other sequence(s) detected in SWISS-PROT: NONE.
-
- -Consensus pattern: R-C-[LIVM]-x-C-x-R-C-[LIVM]-x-F
- [The three C's are putative 4Fe4S ligands]
- -Sequences known to belong to this class detected by the pattern: ALL, except
- for NQO3 and nuoG.
- -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).
-