Body temperature-related structural transitions of monotremal and human hemoglobin
Body temperature-related structural transitions of monotremal and human hemoglobin
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DOI：
10.1529/biophysj.106.087809
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发表时间：
2006-10-01
影响因子：
3.4
通讯作者：
Artmann, G. M.
中科院分区：
文献类型：
--
作者：
Digel, I.;Maggakis-Kelemen, Ch.;Artmann, G. M.
在这项研究中，温度相关的结构变化进行了研究，在人类，鸭嘴兽（Ornithorhynchus anatinus，体温Tb = 31-33摄氏度），针鼹（Tachyglossus aculeatus，体温Tb 32-33摄氏度）血红蛋白使用圆二色光谱和动态光散射。测量血红蛋白在222 +/-2 nm处的平均流体动力学半径（Rh）和椭圆率（F-obs）的分数（归一化）变化。温度从25 ° C逐步变化到45 ° C。在36-37摄氏度之间的临界温度T-C的人血红蛋白的结构转变的存在先前通过微量吸液管抽吸实验，粘度计，和圆二色光谱显示。基于光散射测量，这项研究证明了在Tc的分子聚集的发病。在两种不同的单孔类血红蛋白（针鼹鼠和鸭嘴兽）中，发现临界转变温度在32-33摄氏度之间，接近物种的体温Tb。这些数据表明，结构转变的临界温度Tc和物种的体温Tb的相关性不仅仅是巧合，而是一种更普遍的结构现象，可能包括许多其他蛋白质。
In this study, temperature-related structural changes were investigated in human, duck-billed platypus (Ornithorhynchus anatinus, body temperature T-b = 31-33 degrees C), and echidna (Tachyglossus aculeatus, body temperature Tb 32-33 degrees C) hemoglobin using circular dichroism spectroscopy and dynamic light scattering. The average hydrodynamic radius (Rh) and fractional (normalized) change in the ellipticity (F-obs) at 222 +/- 2 nm of hemoglobin were measured. The temperature was varied stepwise from 25 degrees C to 45 degrees C. The existence of a structural transition of human hemoglobin at the critical temperature T-c between 36-37 degrees C was previously shown by micropipette aspiration experiments, viscosimetry, and circular dichroism spectroscopy. Based on light-scattering measurements, this study proves the onset of molecular aggregation at Tc. In two different monotremal hemoglobins (echidna and platypus), the critical transition temperatures were found between 32-33 degrees C, which are close to the species' body temperature Tb. The data suggest that the correlation of the structural transition's critical temperature Tc and the species' body temperature Tb is not mere coincidence but, instead, is a more widespread structural phenomenon possibly including many other proteins.