Identification of the NADH-binding subunit of energy-transducing NADH-quinone oxidoreductase (NDH-1) of thermus thermophilus HB-8.
The energy-transducing NADH--quinone oxidoreductase (NDH-1) isolated from Thermus thermophilus HB-8 is composed of approximately 10 unlike polypeptides and contains noncovalently bound FMN and at least three iron-sulfur clusters [Yagi, T., Hon-nami, K., and Ohnishi, T. (1988) Biochemistry 27, 2008-2013]. When NDH-1 of T. thermophilus HB-8 was irradiated by short UV light in the presence of [adenylate-32P]NADH or [adenylate-32P]NAD, radioactivity was incorporated into a single polypeptide of Mr 47,000. The labeling of the Mr 47,000 polypeptide was diminished when UV irradiation of the enzyme complex with [adenylate-32P]NAD was carried out in the presence of NADH or deamino-NADH which act as substrates for the NDH-1, but not in the presence of NADP(H) or AMP which act neither as substrates nor as competitive inhibitors. These results strongly suggest that the Mr 47,000 polypeptide is an NADH-binding subunit of the NDH-1 of T. thermophilus HB-8.
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Department of Molecular and Experimental Medicine, Research Institute of Scripps Clinic, La Jolla, California 92037.
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D000249:Adenosine Monophosphate / Q000494:pharmacology; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D001665:Binding Sites; D002417:Cattle; D007700:Kinetics; D046911:Macromolecular Substances; D009206:Myocardium / Q000201:enzymology; D009243:NAD / Q000378:metabolism*; D016660:NAD(P)H Dehydrogenase (Quinone); D009249:NADP / Q000494:pharmacology; D010084:Oxidation-Reduction; D010231:Paracoccus denitrificans / Q000201:enzymology; D011808:Quinone Reductases / Q000378:metabolism*; D013824:Thermus / Q000201:enzymology
D000596:Amino Acids; D046911:Macromolecular Substances; D009243:NAD; D000249:Adenosine Monophosphate; D009249:NADP; D016660:NAD(P)H Dehydrogenase (Quinone); D011808:Quinone Reductases