Zickermann V, Barquera B, Wikström M, Finel M
Helsinki Bioenergetics Group, Department of Medical Chemistry, University of Helskinki, Finland.
Biochemistry. 1998 Aug 25;37(34):11792-6. doi: 10.1021/bi9810555.
The human mitochondrial ND1/3460 mutation changes Ala52 to Thr in the ND1 subunit of Complex I, and causes Leber's hereditary optic neuropathy (LHON) [Huoponen et al. (1991) Am. J. Hum. Genet. 48, 1147]. We have used a bacterial counterpart of Complex I, NDH-1 from Paracoccus denitrificans, for studying the effect of mutations in the ND1 subunit on the enzymatic activity. The LHON mutation as well as several other mutations in strictly conserved amino acids in its vicinity were introduced into the NQO8 subunit of NDH-1, a bacterial homologue of ND1. The enzymatic activity of the mutants in the presence of hexammineruthenium (rotenone-insensitive) and ubiquinone-1 (rotenone-sensitive) were assayed. In addition, the kinetics of the interaction of selected mutant enzymes with ubiquinone-1, ubiquinone-2, and decylubiquinone was studied. The results suggest that the mutated residues play an important role in ubiquinone reduction by Complex I.
人类线粒体ND1/3460突变使复合体I的ND1亚基中的丙氨酸52变为苏氨酸，导致Leber遗传性视神经病变（LHON）[霍波宁等人（1991年）《美国人类遗传学杂志》48卷，第1147页]。我们使用了复合体I的细菌对应物，反硝化副球菌的NDH-1，来研究ND1亚基中的突变对酶活性的影响。将LHON突变以及其附近严格保守氨基酸中的其他几个突变引入到NDH-1的NQO8亚基中，NDH-1的NQO8亚基是ND1的细菌同源物。测定了突变体在六氨合钌（对鱼藤酮不敏感）和泛醌-1（对鱼藤酮敏感）存在下的酶活性。此外，还研究了选定突变酶与泛醌-1、泛醌-2和癸基泛醌相互作用的动力学。结果表明，突变残基在复合体I还原泛醌过程中起重要作用。
