Yamaguchi M, Belogrudov G I, Matsuno-Yagi A, Hatefi Y
Division of Biochemistry, Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA, USA.
Eur J Biochem. 2000 Jan;267(2):329-36. doi: 10.1046/j.1432-1327.2000.00999.x.
Direct photoaffinity labeling of purified bovine heart NADH:ubiquinone oxidoreductase (complex I) with 32P-labeled NAD(H), NADP(H) and ADP has shown that five polypeptides become labeled, with molecular masses of 51, 42, 39, 30, and 18-20 kDa. The 51 and the 30-kDa polypeptides were labeled with either [32P]NAD(H), [32P]NADP(H) or [beta-32P]ADP. The 42-kDa polypeptide was labeled with [32P]NAD(H) and to a small extent with [beta-32P]ADP. It was not labeled with [32P]NADP(H). The 39-kDa polypeptide was labeled with [32P]NADPH and to a small extent with [beta-32P]ADP. Our previous studies had shown that this subunit also binds NADP, but not NAD(H) [Yamaguchi, M., Belogrudov, G.I. & Hatefi, Y. (1998) J. Biol. Chem. 273, 8094-8098]. The 18-20-kDa polypeptide was labeled only with [32P]NADPH. Among these polypeptides, the 51-kDa subunit is known to contain FMN and a [4Fe-4S] cluster, and is the NAD(P)H-binding subunit of the primary dehydrogenase domain of complex I. The possible roles of the other nucleotide-binding subunits of complex I have been discussed.
用³²P标记的NAD(H)、NADP(H)和ADP对纯化的牛心NADH：泛醌氧化还原酶（复合体I）进行直接光亲和标记，结果表明有5种多肽被标记，其分子量分别为51、42、39、30和18 - 20 kDa。51 kDa和30 kDa的多肽可被[³²P]NAD(H)、[³²P]NADP(H)或[β - ³²P]ADP标记。42 kDa的多肽可被[³²P]NAD(H)标记，也能被少量的[β - ³²P]ADP标记，但不能被[³²P]NADP(H)标记。39 kDa的多肽可被[³²P]NADPH标记，也能被少量的[β - ³²P]ADP标记。我们之前的研究表明，该亚基也结合NADP，但不结合NAD(H) [山口，M.，别洛格鲁多夫，G.I. & 哈泰菲，Y. (1998) J. Biol. Chem. 273, 8094 - 8098]。18 - 20 kDa的多肽仅被[³²P]NADPH标记。在这些多肽中，已知51 kDa亚基含有FMN和一个[4Fe - 4S]簇，是复合体I初级脱氢酶结构域的NAD(P)H结合亚基。文中还讨论了复合体I其他核苷酸结合亚基可能的作用。
