Mass Spectrometry Methods for Measuring Protein Stability

Abstract

Mass spectrometry is a central technology in the life sciences, providing our most comprehensive account of the molecular inventory of the cell. In parallel with developments in mass spectrometry technologies targeting such assessments of cellular composition, mass spectrometry tools have emerged as versatile probes of biomolecular stability. In this review, we cover recent advancements in this branch of mass spectrometry that target proteins, a centrally important class of macromolecules that accounts for most biochemical functions and drug targets. Our efforts cover tools such as hydrogen–deuterium exchange, chemical cross-linking, ion mobility, collision induced unfolding, and other techniques capable of stability assessments on a proteomic scale. In addition, we focus on a range of application areas where mass spectrometry-driven protein stability measurements have made notable impacts, including studies of membrane proteins, heat shock proteins, amyloidogenic proteins, and biotherapeutics. We conclude by briefly discussing the future of this vibrant and fast-moving area of research.

Disassembly Mechanisms and Energetics of Polymetallic Rings and Rotaxanes

“…We have shown that energy-resolved MS 2 and IM-MS coupled with DFT combine effectively to characterize polymetallic complexes in the gas-phase, yielding information on the compounds’ disassembly, energetics, and conformational dynamics. Our study demonstrates that these methods, more commonly applied to the disassembly of protein complexes, ,− can be usefully applied for supramolecular and inorganic chemistry. The results show that the stability of the studied ring and rotaxane ions is tuned by altering the d-metal composition in the heterometallic ring, the end groups in the thread, and the charge carrying ion, providing a framework to follow in for the future design of self-assembled polymetallic complexes.…”

Laser Heating Nanoelectrospray Emitters for Fast Protein Melting Measurements with Mass Spectrometry

“…A variety of standard techniques are used to measure protein melting temperatures, including circular dichroism (CD) spectroscopy, , fluorescence/ultraviolet–visible (UV–vis) spectrophotometry, , and differential scanning calorimetry (DSC). , These techniques generally require purified protein samples to avoid overlapping signals or transitions that lead to uncertainties in measured T m values. Mass spectrometry (MS) has also been used to measure protein melting temperatures and has the advantage that purified samples are not required if proteins have different masses. , MS-based methods of determining T m values also have the advantage of high sensitivity with little sample required, and changes in protein conformation including folding/unfolding intermediate structures that are kinetically trapped during the ionization process, − can be identified based on either the abundance of each charge state − or by using ion mobility spectrometry. ,− …”

“…Mass spectrometry (MS) has also been used to measure protein melting temperatures and has the advantage that purified samples are not required if proteins have different masses. 13,14 MS-based methods of determining T m values also have the advantage of high sensitivity with little sample required, and changes in protein conformation including folding/unfolding intermediate structures that are kinetically trapped during the ionization process, 15−17 can be identified based on either the abundance of each charge state 18−20 or by using ion mobility spectrometry. 16,20−23 Several different variable-temperature electrospray ionization (vT-ESI) sources have been developed to change solution temperature during electrospray.…”

Simulation of Energy-Resolved Mass Spectrometry Distributions from Surface-Induced Dissociation

“…Data from tandem mass spectrometry (MS/MS) experiments increasingly provide valuable structural information for proteins and protein complexes. An assortment of different techniques can be used to measure various types of structural information. − For example, ion mobility (IM) can provide information on size and shape, − chemical cross-linking (XL) can provide information on residue distances and contacts, − and covalent labeling can provide information on solvent accessibility and flexibility of residues. − The resulting structural information can then be used to better understand the roles of the specific proteins in biological processes. These sparse data have also been combined with computational modeling methods , to improve the accuracy of structural predictions. − …”