Characteristics of the paramagnetic 1H-NMR spectra of the ferricytochrome c-551 family.
Characteristics of the paramagnetic 1H-NMR spectra of the ferricytochrome c-551 family.
复制标题
铁细胞色素 c-551 家族的顺磁 1H-NMR 谱的特征。
DOI：
10.1111/j.1432-1033.1994.tb20037.x
复制
发表时间：
1994
期刊：
影响因子：
--
通讯作者：
Hooper,AB
中科院分区：
文献类型：
--
作者：
Timkovich,R;Cai,M;Zhang,B;Arciero,DM;Hooper,AB
血红素质子共振已分配给从四种不同细菌中分离的ferricytochromesc-551。虽然现有的结构信息表明，四种细胞色素在溶液中具有非常相似的构象，包括甲硫氨酸配体硫键的手性，顺磁位移共振的化学位移是令人惊讶的不同，比以前报道的同源系列的ferricytochromes。共振在化学位移和位移的温度依赖性方面进行了对比，这对某些特定的质子产生了非常强的反居里效应。非甲基血红素共振确实显示出一组近似保守的化学位移，但血红素甲基基团显示出宽范围的值。121位血红素甲基总是出现频率最高的血红素甲基，但其他甲基的相对位置可能会发生变化。71位血红素甲基总是表现出强烈的反居里行为，而121位甲基则表现出正常的居里行为。其他甲基的行为是可变的。将讨论观察范围的可能原因。尽管它们的NMR存在差异，但所有ferricytochromesc-551都表现出与膜结合细胞色素还原酶系统相当的电子转移速率。
Heme proton resonances have been assigned for ferricytochromesc‐551 isolated from four distinct species of bacteria. While the available structure information indicates that the four cytochromes have very similar conformations in solution, including the chirality of the methionine ligand sulfur bond, the chemical shifts of the paramagnetically shifted resonances are surprisingly different, more so than has been previously reported for a homologous series of ferricytochromes. The resonances are contrasted in terms of chemical shift and the temperature dependence of the shift, which gives rise to a very strong anti‐Curie effect for some specific protons. Non‐methyl heme resonances do display an approximately conserved set of chemical shifts, but the heme methyl groups demonstrate a wide range of values. The 121heme methyl group is always the highest frequency heme methyl, but the relative positions of the other methyl groups may change. The 71heme methyl group always displayed strong anti‐Curie behavior, while the 121methyl group displayed normal Curie behavior. The behavior of the other methyl groups was variable. Possible reasons for the range of observations will be discussed. In spite of their NMR differences, all the ferricytochromesc‐551 demonstrated comparable electron‐transfer rates to a membrane‐bound cytochrome reductase system.