Hydrogen exchange studies of respiratory proteins. IV. A new, ligand-responsive class in hemoglobin.
Hydrogen exchange studies of respiratory proteins. IV. A new, ligand-responsive class in hemoglobin.
复制标题
呼吸蛋白的氢交换研究。
DOI：
--
复制
发表时间：
1974
影响因子：
4.8
通讯作者：
S. Englander
中科院分区：
文献类型：
--
作者：
R. Ghose;S. Englander
摘要作为一项正在进行的调查的一部分，研究了血红蛋白的氢交换曲线的早期区域，以寻找响应变构结构变化的氢。使用了以前为这种研究设计的差异氢交换法。在每个亚基研究的大约25个氢中，7个通过加速14倍的交换速率响应配体结合;其余的是配体无关的。反应氢在配体和脱氧血红蛋白中形成一级动力学类，这进一步支持了氢交换的“呼吸”图。观察到的交换率的增加表明，持有这些氢的片段在变构转变中经历了价值+1.5 Cal的净结构自由能变化。
Abstract As part of an ongoing survey, the early time region of hemoglobin's hydrogen exchange curve was studied to find hydrogens that respond to allosteric structure change. A difference hydrogen exchange method, previously designed for this kind of study, was used. Among the approximately 25 hydrogens per subunit studied, 7 respond to ligand binding by accelerating 14-fold in exchange rate; the remainder are ligand-indifferent. The responsive hydrogens form a first order kinetic class in both liganded and deoxyhemoglobin, and this gives further support to the "breathing" picture of hydrogen exchange. The increase in exchange rate observed indicates that the segment holding these hydrogens experiences a net structural free energy change worth +1.5 Cal in the allosteric transition.