Protein structure determination using NMR is dependent on experimentally acquired distance restraints. Often, however, an insufficient number of these restraints are available for determining a protein's correct fold, much less its detailed three-dimensional structure. In consideration of this problem, we propose a simple means to acquire supplemental structural restraints from protein surface accessibilities using solvent saturation transfer to proteins (SSTP), based on the principles of paramagnetic chemical-exchange saturation transfer. Here, we demonstrate the utility of SSTP in structure calculations of two proteins, TSG101 and ubiquitin. The observed SSTP was found to be directly proportional to solvent accessibility. Since SSTP does not involve the direct excitation of water, which compromises the analysis of protein protons entangled in the breadth of the water resonance, it has an advantage over conventional water-based magnetization transfers. Inclusion of structural restraints derived from SSTP improved both the precision and accuracy of the final protein structures in comparison to those determined by traditional approaches, when using minimal amounts of additional structural data. Furthermore, we show that SSTP can detect weak protein-protein interactions which are unobservable by chemical shift perturbations.

中文翻译：

---

溶剂饱和转移至蛋白质（SSTP），用于蛋白质的结构和功能表征。

使用NMR确定蛋白质结构取决于实验获得的距离限制。但是，通常没有足够数量的这些约束来确定蛋白质的正确折叠，而不是其详细的三维结构。考虑到此问题，我们基于顺磁性化学交换饱和转移的原理，提出了一种简单的方法，利用溶剂饱和转移至蛋白质（SSTP），从蛋白质表面可及性获得补充的结构限制。在这里，我们展示了SSTP在两种蛋白质TSG101和泛素的结构计算中的效用。发现观察到的SSTP与溶剂可及性成正比。由于SSTP不涉及水的直接激发，它折衷了纠缠在水共振宽度内的蛋白质质子的分析，它比常规的水基磁化转移具有优势。与使用传统方法确定的蛋白质相比，当使用最少数量的其他结构数据时，包含源自SSTP的结构限制提高了最终蛋白质结构的精确度和准确性。此外，我们表明SSTP可以检测到微弱的蛋白质-蛋白质相互作用，这是化学位移扰动所无法观察到的。使用最少数量的其他结构数据时。此外，我们表明SSTP可以检测到微弱的蛋白质-蛋白质相互作用，这是化学位移扰动所无法观察到的。使用最少数量的其他结构数据时。此外，我们表明SSTP可以检测到微弱的蛋白质-蛋白质相互作用，这是化学位移扰动所无法观察到的。