Li Y, Leonard K, Weiss H
Eur J Biochem. 1981 May;116(1):199-205. doi: 10.1111/j.1432-1033.1981.tb05319.x.
Cytochrome c1 is a subunit of ubiquinol--cytochrome c reductase (EC 1.10.2.2). In Neurospora crassa wild type 74A grown in the presence of chloramphenicol, the subunit is inserted only into the bilayer of the mitochondrial inner membranes without associating with other proteins. From these modified membranes a monodisperse (cytochrome c1)-Triton complex was isolated by subjecting the Triton-solubilized membranes to affinity chromatography on immobilized cytochrome c. A water-soluble pentamer of cytochrome c1 was prepared from the (cytochrome c1)-Triton complex by removing the detergent. By limited proteolytic digestion of the cytochrome c1-Triton complex with chymotrypsin, a water-soluble monomeric cytochrome c1 was prepared which has a molecular weight of only 24 000 as compared to 31 000 of the membrane-bound cytochrome c1. The 24 000-Mr cytochrome c1 and the 31 000-Mr cytochrome c1 have same light absorption spectra and cytochrome-c-binding properties. These results are used to propose the following model. Cytochrome c1 consists of a large hydrophilic part and a small hydrophobic part. The hydrophilic part extends from the mitochondrial inner membrane into the intermembrane space. This part carries the heme and interacts with cytochrome c. The hydrophobic part anchors the cytochrome c1 to the bilayer.
细胞色素c1是泛醇-细胞色素c还原酶（EC 1.10.2.2）的一个亚基。在氯霉素存在下生长的粗糙脉孢菌野生型74A中，该亚基仅插入线粒体内膜的双层中，而不与其他蛋白质结合。通过将Triton溶解的膜在固定化细胞色素c上进行亲和层析，从这些修饰的膜中分离出单分散的（细胞色素c1）-Triton复合物。通过去除去污剂，从（细胞色素c1）-Triton复合物中制备了细胞色素c1的水溶性五聚体。用胰凝乳蛋白酶对细胞色素c1-Triton复合物进行有限的蛋白水解消化，制备了一种水溶性单体细胞色素c1，其分子量仅为24000，而膜结合的细胞色素c1分子量为31000。24000分子量的细胞色素c1和31000分子量的细胞色素c1具有相同的光吸收光谱和细胞色素c结合特性。这些结果被用于提出以下模型。细胞色素c1由一个大的亲水部分和一个小的疏水部分组成。亲水部分从线粒体内膜延伸到膜间隙。这部分携带血红素并与细胞色素c相互作用。疏水部分将细胞色素c1锚定在双层膜上。
