Morishima I, Ogawa S, Yonezawa T, Iizuka T
Biochim Biophys Acta. 1978 Jan 25;532(1):48-56. doi: 10.1016/0005-2795(78)90446-4.
The structure of the heme environment of horse heart ferric cytochrome c was examined in the presence of various nitrogenous bases at several temperatures with the aid of hyperfine shifted proton NMR spectra at 220 MHz. The resonance positions and line widths of the signals for the peripheral methyl groups of the heme exhibited distinctive features of its low-spin state characteristic of each external ligand. In the imidazole complex of ferric cytochrome c, remarkable line sharpening of the heme-linked proton signals was encountered on raising the temperature. This may be related to the apoprotein perturbation on the binding of external ligand to the heme iron. These spectral peculiarities were discussed in relation to the electronic structure of the heme, the basicity of the external ligand and the van der Waals contact interaction between heme side chains and apoprotein.
借助220兆赫的超精细位移质子核磁共振谱，在不同温度下于多种含氮碱存在的情况下，对马心铁细胞色素c的血红素环境结构进行了研究。血红素外围甲基基团信号的共振位置和线宽展现出了每种外部配体低自旋态特征的独特特性。在铁细胞色素c的咪唑配合物中，升高温度时会遇到血红素连接质子信号显著的线锐化现象。这可能与外部配体与血红素铁结合时脱辅基蛋白的扰动有关。结合血红素的电子结构、外部配体的碱性以及血红素侧链与脱辅基蛋白之间的范德华接触相互作用，对这些光谱特性进行了讨论。
