Thomas M A, Delsuc M A, Beloeil J C, Lallemand J Y
Biochem Biophys Res Commun. 1987 Jun 30;145(3):1098-104. doi: 10.1016/0006-291x(87)91550-6.
1H-NMR spectroscopy has been used to study the modifications of certain characteristic resonances of the Hansenula anomala yeast cytochrome c on binding to its specific reductase (flavocytochrome b2) or to the isolated cytochrome domain obtained from the entire molecule. Normal titration curves are observed for the resonances at 37.8 ppm assigned to heme c methyl 8 and at 19.4 ppm, line of cytochrome b2 spectrum. In contrast, the shifts near 3.2 and 3.4 ppm for trimethyl-lysine resonances of this cytochrome c present abnormal titration curves, saturation being apparently reached at low molar (cytochrome b2)/(cytochrome c) ratio. An interpretation is proposed in terms of shifts due to local conformational transitions induced by reductase binding but not rapidly reversible upon dissociation.
1H-核磁共振光谱已被用于研究异常汉逊酵母细胞色素c与它的特异性还原酶（黄素细胞色素b2）或从整个分子中分离得到的细胞色素结构域结合时某些特征共振峰的变化。对于归属于血红素c甲基8的37.8 ppm处的共振峰以及细胞色素b2光谱的19.4 ppm处的谱线，观察到了正常的滴定曲线。相比之下，该细胞色素c的三甲基赖氨酸共振峰在3.2和3.4 ppm附近的位移呈现出异常的滴定曲线，在低摩尔比（细胞色素b2）/（细胞色素c）时显然就达到了饱和。根据还原酶结合诱导的局部构象转变引起的位移提出了一种解释，但在解离时这种转变不是快速可逆的。
