Two decades of studying non-covalent biomolecular assemblies by means of electrospray ionization mass spectrometry

Abstract

Mass spectrometry (MS) is a recognized approach for characterizing proteins and the complexes they assemble into. This application of a long-established physico-chemical tool to the frontiers of structural biology has stemmed from experiments performed in the early 1990s. While initial studies focused on the elucidation of stoichiometry by means of simple mass determination, developments in MS technology and methodology now allow researchers to address questions of shape, inter-subunit connectivity and protein dynamics. Here, we chart the remarkable rise of MS and its application to biomolecular complexes over the last two decades.

Combining tandem mass spectrometry with ion mobility separation to determine the architecture of polydisperse proteins

“…1A, upper panel) matches closely our previous MS results [38,48]. Examination of the IM dimension reveals that each charge state has a narrow and approximately Gaussian ATD, suggesting a single conformational family, and after calibration reveals a measured CCS of 8760 Å [2]. This compares favourably to that expected from the crystal structure (8702 Å [2]), suggesting that HSP16.9 is present in a form closely resembling that in solution, with the absence of significant compaction or unfolding in the vacuum of the mass spectrometer.…”

“…This is because most techniques generally only provide data averaged over all molecules in solution and are therefore best suited to the study of highly homogeneous samples. Mass spectrometry (MS) has evolved into a technique capable of transferring proteins and the assemblies they form into the gas phase, while maintaining the majority of intra-and intermolecular non-covalent interactions [1][2][3][4][5][6][7][8]. As a result, it has the ability to provide a snapshot of the equilibrium distribution of molecules in solution by isolating them from each other in vacuum, and analysing them according to their mass-to-charge (m/z) ratio.…”

Protein Structural Studies by Traveling Wave Ion Mobility Spectrometry: A Critical Look at Electrospray Sources and Calibration Issues

“…Given the purported Bsoftness advantage^of nanoESI [32,45], we examined whether the properties of gaseous Ubq, Cyt, hMb, and Hb depend on the type of electrospray source. In contrast to hMb 8+ Ubq 5+ Figure 3.…”

“…However, nanoESI tends to be less robust in terms of signal stability and reproducibility than regular ESI [43,44]. It is often implied that nanoESI is better suited for preserving proteinligand interactions [32,45], although experimental evidence suggests that this is not necessarily the case [46][47][48]. A closely related question is whether nanoESI is better suited for studies that aim to preserve solution structures.…”

Opposite Structural Effects of Epigallocatechin-3-gallate and Dopamine Binding to α-Synuclein

“…Native mass spectrometry relies on gentle transfer of proteins and their complexes from solution into the gas phase of the mass spectrometer, without major structural rearrangements or disruption of non-covalent interactions [25][26][27][28] . As such it is especially useful for detecting non-covalent ligand binding 29,30 .…”