Abstract：
The analysis of pressure induced changes in the chemical shift of proteins allows statements on structural fluctuations proteins exhibit at ambient pressure. The inherent issue of separating general pressure effects from structural related effects on the pressure dependence of chemical shifts has so far been addressed by considering the characteristics of random coil peptides on increasing pressure. In this work, chemically and pressure denatured states of the cold shock protein B from Bacillus subtilis (BsCspB) have been assigned in 2D 1H-15N HSQC NMR spectra and their dependence on increasing hydrostatic pressure has been evaluated. The pressure denatured polypeptide chain has been used to separate general from structural related effects on 1H and 15N chemical shifts of native BsCspB and the implications on the interpretation of pressure induced changes in the chemical shift regarding the structure of BsCspB are discussed. It has been found that the ensemble of unstructured conformations of BsCspB shows different responses to increasing pressure than random coil peptides do. Thus, the approach used for considering the general effects that arise when hydrostatic pressure increases changes the structural conclusions that are drawn from high pressure NMR spectroscopic experiments that rely on the analysis of chemical shifts.
摘要：
对压力引起的蛋白质化学位移变化的分析可以说明蛋白质在环境压力下表现出的结构波动。迄今为止，通过考虑随机卷曲肽在增加压力时的特性，已经解决了将一般压力效应与结构相关效应对化学位移的压力依赖性的固有问题。在这项工作中,来自枯草芽孢杆菌（BsCspB）的冷休克蛋白B的化学和压力变性状态已在2D1H-15NHSQCNMR光谱中指定，并评估了它们对静水压力增加的依赖性。压力变性的多肽链已用于将对天然BsCspB的1H和15N化学位移的一般与结构相关的影响分开，并讨论了压力诱导的化学位移变化对解释BsCspB结构的影响。已经发现，BsCspB的非结构化构象的集合对增加的压力显示出与无规卷曲肽不同的响应。因此，用于考虑当静水压力增加时产生的一般效应的方法改变了从依赖于化学位移分析的高压NMR光谱实验得出的结构结论。
