Saruta F, Hirawake H, Takamiya S, Ma Y C, Aoki T, Sekimizu K, Kojima S, Kita K
Department of Parasitology, University of Tokyo, Japan.
Biochim Biophys Acta. 1996 Aug 7;1276(1):1-5. doi: 10.1016/0005-2728(96)00070-9.
Complex II in the mitochondria of the adult parasitic nematode, Ascaris suum, exhibits high fumarate reductase activity in addition to succinate dehydrogenase activity and plays a key role in the anaerobic energy metabolism of the worm. In this study, the amino acid sequence of the small subunit of cytochrome b558 (cybS) in adult complex II was deduced from the cDNA isolated by immunoscreening an A. suum muscle cDNA library. Histidine residues, which are possible heme axial ligands in cytochrome b558, were found in the second transmembrane segment of the subunit. This is the first report of the primary structure of the small subunit in the two-subunit cytochrome b in mitochondrial complex II from a multicellular eukaryote.
成年寄生线虫猪蛔虫线粒体中的复合物II除具有琥珀酸脱氢酶活性外，还表现出高延胡索酸还原酶活性，在该蠕虫的无氧能量代谢中起关键作用。在本研究中，通过免疫筛选猪蛔虫肌肉cDNA文库分离得到的cDNA推导了成年复合物II中细胞色素b558小亚基（cybS）的氨基酸序列。在该亚基的第二个跨膜区段发现了可能作为细胞色素b558中血红素轴向配体的组氨酸残基。这是多细胞真核生物线粒体复合物II中双亚基细胞色素b小亚基一级结构的首次报道。
