Introduction: Hydrogen–deuterium exchange (HDX) mass spectrometry (MS) is ideal for monitoring the protein folding and unfolding. The exchange of a deuterium in solution for an amide hydrogen in a protein can be very different depending on the degree of folding and protection of backbone amide positions. Molecular chaperones that assist with protein folding in vivo are necessary for folding of many substrate (client) proteins. HDX MS provides valuable insight into what chaperones are doing in protein folding and how they are doing it.

Areas covered: Application of HDX MS to the protein folding problem was desirable from the outset of the technique, but technical issues prohibited many studies. In the last 20 years, conformational changes of chaperones themselves (e.g., GroEL/GroES, Hsp70, and Hsp90) have been studied. Studies of interactions between chaperones, co-chaperones, and substrate proteins have revealed binding interfaces, allosteric conformational changes, and remodeling of components during various chaperone cycles. Experiments elucidating how chaperones contribute to and enhance the folding pathway of substrate proteins have been demonstrated.

Expert opinion: Technical issues that once prevented the analysis of chaperones have largely been resolved, permitting exciting comprehensive HDX MS studies of folding pathways during chaperone-assisted protein folding.

简介：氢-氘交换（HDX）质谱（MS）是监测蛋白质折叠和展开的理想选择。溶液中氘与蛋白质中酰胺氢的交换可能有很大不同，这取决于骨架酰胺位置的折叠程度和保护程度。协助体内蛋白质折叠的分子伴侣对于许多底物（客户）蛋白质的折叠是必需的。HDX MS可提供有关分子伴侣在蛋白质折叠中的作用及其作用方式的宝贵见解。

涉及的领域：从技术开始就希望将HDX MS用于蛋白质折叠问题，但是技术问题使许多研究无法进行。在最近的20年中，已经研究了伴侣蛋白本身的构象变化（例如，GroEL / GroES，Hsp70和Hsp90）。伴侣，伴侣伴侣和底物蛋白之间相互作用的研究揭示了在各种伴侣周期中的结合界面，构构构象变化和组分重塑。已经阐明了阐明伴侣分子如何促进和增强底物蛋白折叠途径的实验。

专家意见：曾经阻止了分子伴侣分析的技术问题已经得到了解决，这使得分子伴侣辅助蛋白折叠过程中令人兴奋的HDX MS折叠途径研究变得更加精彩。