Suzuki H, Hosokawa Y, Toda H, Nishikimi M, Ozawa T
Department of Biomedical Chemistry, Faculty of Medicine, University of Nagoya, Japan.
Biochem Biophys Res Commun. 1988 Oct 31;156(2):987-94. doi: 10.1016/s0006-291x(88)80941-0.
The ubiquinone-binding protein (QP-C) is a nuclear-encoded component of ubiquinol-cytochrome c oxidoreductase in the mitochondrial respiratory chain and plays an important role in electron transfer as a ubiquinone-QP-C complex. We obtained a partial cDNA for rat liver QP-C by screening a lambda gt11 rat liver cDNA library using antiserum directed against bovine heart QP-C. Using this cDNA as a probe, a cDNA clone was isolated from a human fibroblast cDNA library by colony hybridization. The total length of the cloned cDNA was 518 base pairs with an open reading frame of 333 base pairs. The 111-amino acid sequence deduced from the nucleotide sequence of the cDNA is 85% homologous to that of bovine QP-C and contains only a single additional amino-terminal methionine. This implies that the human QP-C is synthesized without a presequence which is required for import of most nuclear-encoded mitochondrial proteins into mitochondria.
泛醌结合蛋白（QP-C）是线粒体呼吸链中泛醇-细胞色素c氧化还原酶的一种核编码成分，作为泛醌-QP-C复合物在电子传递中起重要作用。我们使用针对牛心QP-C的抗血清筛选λgt11大鼠肝脏cDNA文库，获得了大鼠肝脏QP-C的部分cDNA。以该cDNA为探针，通过菌落杂交从人成纤维细胞cDNA文库中分离出一个cDNA克隆。克隆的cDNA全长518个碱基对，开放阅读框为333个碱基对。从cDNA的核苷酸序列推导的111个氨基酸序列与牛QP-C的序列同源性为85%，且仅在氨基末端多一个甲硫氨酸。这意味着人QP-C的合成没有大多数核编码线粒体蛋白导入线粒体所需的前导序列。
