The determination of disulfide connectivity and conformation by the SAIL method

蛋白质中二硫键连通性和构象的测定对于理解蛋白质的结构稳定性至关重要。但是，还没有确定对它们进行调查的方法。本文提出了一种观察含有两个不同半胱氨酸残基的b质子的跨桥noe的方法。在传统的均匀同位素标记蛋白质中，由于信号重叠和自旋扩散效应，很难观察到这种NOE。在我们的方法中，除了两个Cys的β-质子外，使用了一种质子完全氘化的蛋白质，这样就可以很容易地确定连性和质子-质子距离。

The determination of disulfide connectivity and conformation in a protein is essential for understanding the structural stability of the protein. However, no method for investigating them has been established. Here, a method for observing cross-bridge NOEs involving two b-protons of different cysteine residues has been developed. In a conventional uniformly isotope-labeled protein, the observation of such a NOE is difficult due to signal overlap and spin diffusion effect. In our approach, a protein whose protons are exclusively deuterated except for the two Cys's β-protons is employed, such that the connectivity and proton-proton distance can readily be determined.