Structure of deoxyhemoglobin Cowtown [His HC3(146) beta----Leu]: origin of the alkaline Bohr effect and electrostatic interactions in hemoglobin.
Structure of deoxyhemoglobin Cowtown [His HC3(146) beta----Leu]: origin of the alkaline Bohr effect and electrostatic interactions in hemoglobin.
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脱氧血红蛋白 Cowtown 的结构 [His HC3(146) beta----Leu]：血红蛋白中碱性玻尔效应和静电相互作用的起源。
DOI：
10.1073/pnas.81.15.4781
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发表时间：
1984
影响因子：
11.1
通讯作者：
Shih,TB
中科院分区：
文献类型：
--
作者：
Perutz,MF;Fermi,G;Shih,TB
血红蛋白 Cowtown [His HC3(146)-beta----Leu] 具有高氧亲和力和一半的碱性玻尔效应。 X射线分析显示COOH末端亮氨酸在两个位置之间处于平衡：一个位置末端羧基和Lys C5(40)α之间的盐桥完整且亮氨酰侧链倾斜于螺旋F和FG的主链原子，另一个位置末端盐桥断裂且亮氨酰侧链接触Pro C2(37)α。结构变化仅限于 COOH 末端附近，表明碱性玻尔效应减半直接归因于组氨酸的损失，而其他地方的结构变化导致其他可电离基团的 pK 值变化没有显着影响。
Hemoglobin Cowtown [His HC3(146)-beta----Leu] exhibits high oxygen affinity and a halved alkaline Bohr effect. X-ray analysis shows the COOH-terminal leucine to be in equilibrium between two positions: one with the salt bridge between the terminal carboxyl and Lys C5(40)alpha intact and the leucyl side chain leaning against main chain atoms of helices F and FG and the other with the terminal salt bridge broken and the leucyl side chain touching Pro C2(37)alpha. Structural changes are confined to the immediate neighborhood of the COOH terminus, showing the halving of the alkaline Bohr effect to be due directly to the loss of the histidine, without significant contributions from changes in pK values of other ionizable groups due to structural changes elsewhere.