Effect of the N-terminal residues on the quaternary dynamics of human adult hemoglobin
Effect of the N-terminal residues on the quaternary dynamics of human adult hemoglobin
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DOI：
10.1016/j.chemphys.2016.02.009
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发表时间：
2016-05-01
期刊：
影响因子：
2.3
通讯作者：
Mizutani, Yasuhisa
中科院分区：
文献类型：
--
作者：
Chang, Shanyan;Mizuno, Misao;Mizutani, Yasuhisa
通过时间分辨共振拉曼光谱研究了配体光解后人血红蛋白的蛋白质动力学。将大肠杆菌表达的两种重组血红蛋白（正常重组血红蛋白和α（V1M）/β（V1M）双突变体）的时间分辨光谱与从血液中纯化的成人血红蛋白（HbA）的时间分辨光谱进行了比较。在所有三个血红蛋白样品的时间分辨光谱中观察到铁-组氨酸伸缩 [v(Fe-His)] 带的频移，表明光解后蛋白质发生了三级和四级变化。 α(V1M)/β(V1M)双突变体的光谱变化在数十微秒范围内与HbA的光谱变化不同，而正常重组血红蛋白的光谱变化与从血液中分离的HbA的光谱变化相似。这些结果表明，N末端的结构变化参与了血红蛋白四级结构变化的第二步。我们讨论这些结果对于理解 HbA1c 变构途径的影响。 (C) 2016 Elsevier B.V. 保留所有权利。
The protein dynamics of human hemoglobin following ligand photolysis was studied by time-resolved resonance Raman spectroscopy. The time-resolved spectra of two kinds of recombinant hemoglobin expressed in Escherichia coli, normal recombinant hemoglobin and the alpha(V1M)/beta(V1M) double mutant, were compared with those of human adult hemoglobin (HbA) purified from blood. A frequency shift of the iron-histidine stretching [v(Fe-His)] band was observed in the time-resolved spectra of all three hemoglobin samples, indicative of tertiary and quaternary changes in the protein following photolysis. The spectral changes of the alpha(V1M)/beta(V1M) double mutant were distinct from those of HbA in the tens of microseconds region, whereas the spectral changes of normal recombinant hemoglobin were similar to those of HbA isolated from blood. These results demonstrated that a structural change in the N-termini is involved in the second step of the quaternary structure change of hemoglobin. We discuss the implications of these results for understanding the allosteric pathway of HbA. (C) 2016 Elsevier B.V. All rights reserved.