Robinson M N, Boswell A P, Huang Z X, Eley C G, Moore G R
Biochem J. 1983 Sep 1;213(3):687-700. doi: 10.1042/bj2130687.
1H-n.m.r. studies of horse, tuna, Candida krusei and Saccharomyces cerevisiae cytochromes c showed that each of the proteins contains a similar cluster of residues at the bottom of the protein that assists in shielding the haem from the solvent. The relative positions of the residues forming these clusters vary continuously with temperature, and they change with the change in protein redox state. This conformational heterogeneity is discussed with reference to the conformational flexibility of cytochrome c around residues 57, 59 and 74. Spectroscopic measurements of pKa values for Lys-55 (horse and tuna cytochromes c) and His-33 and His-39 (C. krusei and S. cerevisiae cytochromes c) are in excellent agreement with expectations based on chemical-modification studies of horse cytochrome c. [Bosshard & Zürrer (1980) J. Biol. Chem. 255, 6694-6699] and on the X-ray-crystallographic structure of tuna cytochrome c [Takano & Dickerson (1981) J. Mol. Biol. 153, 79-94, 95-115].
对马、金枪鱼、克鲁斯假丝酵母和酿酒酵母细胞色素c的1H核磁共振研究表明，每种蛋白质在蛋白质底部都含有一组相似的残基，有助于保护血红素免受溶剂影响。形成这些簇的残基的相对位置随温度连续变化，并且它们会随着蛋白质氧化还原状态的变化而改变。参照细胞色素c在57、59和74位残基周围的构象灵活性讨论了这种构象异质性。对赖氨酸-55（马和金枪鱼细胞色素c）以及组氨酸-33和组氨酸-39（克鲁斯假丝酵母和酿酒酵母细胞色素c）的pKa值进行的光谱测量，与基于对马细胞色素c的化学修饰研究[博斯哈德和祖勒（1980年）《生物化学杂志》255卷，6694 - 6699页]以及金枪鱼细胞色素c的X射线晶体结构[高野和迪克森（1981年）《分子生物学杂志》153卷，79 - 94页，95 - 115页]的预期结果高度一致。
