Shao W, Liu G, Tang W
State Key Laboratory of Coordination Chemistry, Nanjing University, People's Republic of China.
Biochim Biophys Acta. 1995 Apr 27;1248(2):177-85. doi: 10.1016/0167-4838(95)00015-m.
The binding of 1-methylimidazole to the heme iron by displacing Met-80 of cytochrome c has been studied by two-dimensional (2D) exchange spectroscopy. Two components of cytochrome c ligated by 1-methylimidazole (1-MeIm-cyt c) are first identified, which are related to the sterically hindered orientation of 1-methylimidazole by the heme pocket. Based on a matrix formalism, the kinetic parameters are calculated from the 2D peak amplitudes. With the known resonance assignments of cytochrome c, some hyperfine shifted resonances arising from heme peripheral protons and two axial ligands, and some side-chain resonances of the aliphatic and aromatic protons of 1-MeIm-cyt c have been straightforwardly assigned, which provide a clue to ligand-induced electronic and molecular structural changes of the protein.
通过二维（2D）交换光谱研究了1-甲基咪唑通过取代细胞色素c的Met-80与血红素铁的结合。首先鉴定了由1-甲基咪唑连接的细胞色素c（1-MeIm-cyt c）的两个组分，这与血红素口袋对1-甲基咪唑的空间位阻取向有关。基于矩阵形式，从二维峰幅度计算动力学参数。利用细胞色素c的已知共振归属，直接归属了一些来自血红素周边质子和两个轴向配体的超精细位移共振，以及1-MeIm-cyt c的脂肪族和芳香族质子的一些侧链共振，这为配体诱导的蛋白质电子和分子结构变化提供了线索。
