Nuclear magnetic resonance quadrupole relaxation studies of chloride binding to human oxy- and deoxyhaemoglobin.
Nuclear magnetic resonance quadrupole relaxation studies of chloride binding to human oxy- and deoxyhaemoglobin.
复制标题
氯化物与人氧合血红蛋白和脱氧血红蛋白结合的核磁共振四极弛豫研究。
DOI：
10.1016/0022-2836(72)90566-9
复制
发表时间：
1972
影响因子：
5.6
通讯作者：
J. Wyman
中科院分区：
文献类型：
--
作者：
E. Chiancone;J. Norne;S. Forsén;E. Antonini;J. Wyman
氯化物与氧血红蛋白、一氧化碳血红蛋白和脱氧血红蛋白以及肌红蛋白的结合已在核磁共振信号35cl -的超线宽的四极弛豫实验中直接测量。这些测量已经扩展到广泛的条件下，表明血红蛋白中至少有两类氯化物结合位点。高亲和位点是氧连接的，在0.1 ~ 2.5m范围内，nacl脱氧血红蛋白比配体血红蛋白结合更多的氯离子。相反，相应的肌红蛋白衍生物之间不存在这种差异。含氧血红蛋白和脱氧血红蛋白之间氯化物结合的差异可能与血红蛋白中与配体结合相关的构象转变有关，并反映在氯化物对氧平衡的影响上。与ATP的竞争实验表明，高亲和力的氯离子结合位点与有机磷的结合位点相对应。
Chloride binding to oxy-, carbon monoxy- and deoxyhaemoglobin and to myoglobin has been measured directly in quadrupole relaxation experiments on the excess line-width of the nuclear magnetic resonance signals of35Cl−associated with its binding to the protein. The measurements, which have been extended over a wide range of conditions, suggest that in haemoglobin there are at least two classes of chloride binding sites. The high affinity sites are oxygen linked and over the range 0.1 to 2.5m-NaCl deoxyhaemoglobin binds more chloride ions than liganded haemoglobin. In contrast no such difference exists between the corresponding myoglobin derivatives.The difference in chloride binding between oxy- and deoxyhaemoglobin may be correlated with the conformational transitions associated with ligand binding in haemoglobin and is reflected in the effect of chloride on the oxygen equilibrium.Competition experiments with ATP indicate that the high affinity chloride binding sites correspond to those for the organic phosphates.