Shelnutt J A, Rousseau D L, Dethmers J K, Margoliashi E
Proc Natl Acad Sci U S A. 1979 Aug;76(8):3865-9. doi: 10.1073/pnas.76.8.3865.
Raman difference spectra have been obtained for the cytochromes c of a number of species by simultaneous data acquisition from two samples. Frequency differences as small as 0.1 cm-1 can be measured reproducibly by the technique we have developed. In comparisons between cytochromes c isolated from two different species, the frequency differences in the heme vibrational modes range from 0 to 6 cm-1. The vibrational frequencies of the heme are sensitive to the electronic charge density on the porphyrin macrocycle. The frequency differences are interpreted in terms of the influence of the heme-packed aromatic and highly electronegative amino acid side chains on the pi* charge density and distribution on the heme. Such a control of the electronic properties of the heme by the protein may be important for the function of cytochrome c.
通过同时采集两个样品的数据,获得了多个物种细胞色素c的拉曼差光谱。利用我们开发的技术,可以可重复地测量低至0.1 cm-1的频率差异。在比较从两个不同物种分离出的细胞色素c时,血红素振动模式的频率差异范围为0至6 cm-1。血红素的振动频率对卟啉大环上的电子电荷密度敏感。频率差异可以根据血红素周围堆积的芳香族和高电负性氨基酸侧链对血红素上π*电荷密度和分布的影响来解释。蛋白质对血红素电子性质的这种控制可能对细胞色素c的功能很重要。