THE ROLE OF SOLVENT VISCOSITY IN THE DYNAMICS OF PROTEIN CONFORMATIONAL-CHANGES
THE ROLE OF SOLVENT VISCOSITY IN THE DYNAMICS OF PROTEIN CONFORMATIONAL-CHANGES
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DOI：
10.1126/science.1615323
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发表时间：
1992-06-26
期刊：
影响因子：
56.9
通讯作者：
EATON, WA
中科院分区：
文献类型：
--
作者：
ANSARI, A;JONES, CM;EATON, WA
使用纳秒激光测量肌红蛋白在常温下配体解离后的构象变化速率。在低溶剂粘度时，该速率与粘度无关，但在高粘度时，它取决于粘度的近似一次幂的倒数。单分子速率过程的Kramers理论可以用来解释这一结果，如果摩擦项被修改为包括蛋白质和溶剂摩擦。理论和实验表明，在甘油-水的低温(10(7)厘米)下，显著降低肌红蛋白构象变化率的主要因素是甘油-水。也就是说，在低温下，构象亚态可能与其说是“冻结”，不如说是“卡住”。
Nanosecond lasers were used to measure the rate of conformational changes ir myoglobin after ligand dissociation at ambient temperatures. At low solvent viscosities the rate is independent of viscosity, but at high viscosities it depends on approximately the inverse first power of the viscosity. Kramers theory for unimolecular rate processes can be used to explain this result if the friction term is modified to include protein as well as solvent friction. The theory and experiment suggest that the dominant factor in markedly reducing the rate of conformational changes in myoglobin at low temperatures (10(7) centipoise) of the glycerol-water solvent. That is, at low temperatures conformational substates may not be "frozen" so much as "stuck."