用ESR研究水合作用对RNaseA分子动力学性质的影响  

An ESR Study on the Effect of Hydration on the Dynamic Property of RNase A

作　　者：傅亚珍[1] 杨景文[1] 

机构地区：[1]中国科学院生物物理研究所,北京100101

出　　处：《生物化学与生物物理学报》2000年第1期39-42,共4页

基　　金：国家自然科学基金

摘　　要：通过ＲＮａｓｅ Ａ的水合等温线， 确定ＲＮａｓｅ Ａ吸附水时所处的相对湿度及其水合值的关系； 将标记上自旋探针（马来酰亚胺氮氧自由基） 的ＲＮａｓｅ Ａ溶液经透析后冷冻干燥并装入样品管后， 在不同相对湿度下与水相互作用， 待吸附平衡后将样品管密封测其ＥＳＲ波谱， 找出谱图上的Ａｍａｘ与ＲＮａｓｅ Ａ 水合值的关系； 从而建立了含微量水的ＲＮａｓｅ Ａ 分子运动与其水含量关系的检测方法， 得到导致ＲＮａｓｅ Ａ分子开始运动的最低水含量阈值约为每克干酶含水０．２０ ｇ， 即当１ 个ＲＮａｓｅ Ａ 分子周围有约１５２ 个水分子时ＲＮａｓｅ Ａ分子开始运动。A method is described for the measurement of dynamic property of RNase A by ESR under xeric conditions. The relationship between relative humidity and hydration degree of RNase A was determined by hydration isotherm. A solution of RNase A was allowed to react with a solution containing maleimide nitroxide label at 25 ℃, then was dialysed and lyophilized. The stable powder of RNase A maleimide nitroxide label compound was put into the tubules, then was hydrated under different relative humidity for 11 days. After hydration, the tubules were closed and measured by ESR. The relationship between hydration value and A max was detected. The results showed that the lowest water content that could induce motion of RNase A by water is about 0.20 g of water per g of RNase A. That means the motion of RNase A molecule becomes detectable when there are 152 water molecules around one RNase A molecule.

关 键 词：水合作用 RNASE A 电子自旋共振 动力学性质 

分 类 号：Q615[生物学—生物物理学]