人体胰岛素质子交换反应的核磁共振研究

用线型拟合的方法通过核磁共振谱图测得了人体胰岛素R6六聚体中酰胺质子与重氢的交换速度.因为用这一方法对实验谱图进行计算模拟时考虑了核磁共振谱线所提供的所有信息,所以我们获得了化学位移非常接近的蛋白质酰胺质子与重氢的交换速度,这是用其它方法难以得到的数据.结果表明,用本文所述方法获得的酰胺质子的交换速度与由2DNMR计算所得的蛋白质结构有非常好的吻合.在获得酰胺质子交换速度的基础上,本文详细讨论了交换反应速度与蛋白质结构的关系,结果表明,在该蛋白质中影响酰胺质子交换速度大小的因素以强弱顺序排列为:质子在肽链中的位置 > 是否参与形成氢键 > 蛋白质的二级及三级结构.

NMR STUDY OF CHARACTERIZATION OF AMIDE HYDROGEN EXCHANGE IN HUMAN INSULIN R6 HEXAMER

In this paper, the exchange rates of slowly exchanging amide protons in human insulin R6 hexamer were obtained by using NMR Linear Prediction Model Method. Because the method is able to combine information from independent prediction calculation and to exploit differences in chemical shift and exchange rate simultaneously, it allows exchange rates of amide protons with closely spaced signal to be determined. The values of exchange rates from calculation are in good agreement with those from 2D NMR spectrum. The relationship between exchange rates and structure of the protein are discussed in the paper.