Steinhoff H, Lieutenant K, Schlitter J
Institut für Biophysik, Ruhr-Universität Bochum, Bundesrepublik Deutschland.
Z Naturforsch C J Biosci. 1989 Mar-Apr;44(3-4):280-8. doi: 10.1515/znc-1989-3-417.
The residual motion of spin labels bound to cysteine beta 93 of methemoglobin and oxyhemoglobin has been analyzed as a function of temperature and hydration. The rotational diffusion of the whole protein molecule has been prevented or restricted by crystallization, lyophilization or by high viscosity of the solution. The residual motion of the labels is characterized by an angle of the limited motion cone and their rotational correlation time using computer simulations of the EPR spectra. Two types of motion can be separated due to different correlation times and different dependences on temperature and hydration. One of these motional mechanisms can be shown to be determined by protein fluctuations. Correlation times of these fluctuations decrease from 2 X 10(-8) s at T = 220 K to 10(-9) s at T = 300 K in the samples of high water concentration. Strong correlation between the properties of the hydration shell and these fluctuations are observed.
已分析了与高铁血红蛋白和氧合血红蛋白的半胱氨酸β93结合的自旋标记的残余运动随温度和水合作用的变化情况。通过结晶、冻干或溶液的高粘度来阻止或限制整个蛋白质分子的旋转扩散。利用电子顺磁共振光谱的计算机模拟，通过有限运动锥的角度及其旋转相关时间来表征标记的残余运动。由于相关时间不同以及对温度和水合作用的依赖性不同，可以分离出两种类型的运动。这些运动机制之一可证明是由蛋白质波动决定的。在高水浓度样品中，这些波动的相关时间从T = 220 K时的2×10^(-8) s降至T = 300 K时的10^(-9) s。观察到水合壳层性质与这些波动之间存在强相关性。
