Effect of DMSO on Protein Structure and Interactions Assessed by Collision-Induced Dissociation and Unfolding

Abstract

Given the frequent use of DMSO in biochemical and biophysical assays, it is desirable to understand the influence of DMSO concentration on the dissociation or unfolding behavior of proteins. In this study, the effects of DMSO on the structure and interactions of avidin and Mycobacterium tuberculosis (Mtb) CYP142A1 were assessed through collision-induced dissociation (CID) and collision-induced unfolding (CIU) as monitored by nanoelectrospray ionization-ion mobility-mass spectrometry (nESI-IM-MS). DMSO concentrations higher than 4% (v/v) destabilize the avidin tetramer toward dissociation and unfolding, via both its effects on charge state distribution (CSD) as well as at the level of individual charge states. In contrast, DMSO both protects against heme loss and increases the stability of CYP142A1 toward unfolding even up to 40% DMSO. Tandem MS/MS experiments showed that DMSO could modify the dissociation pathway of CYP142A1, while CIU revealed the protective effect of the heme group on the structure of CYP142A1.

Effects of aprotic solvents on the stability of metal‐free superoxide dismutase probed by native electrospray ionization–ion mobility–mass spectrometry

“…[32][33][34] Moreover, we found that these three aprotic solvents can also cause signal broadening ( Figure S3) that represents the formation of solvent adducts. This finding is similar with previous reports on DMSO, 16,17 which can protect against the dissociation of protein by reducing coulomb repulsions due to the low charge state and cooling effect of adduct dissociation.…”

“…And the relative abundance of dimer and monomer of apo‐SOD1 could be evaluated by using the extracted corresponding IM spectrum. The bimodal effect of DMSO on protein charging has been well documented, and its effect on the structure of protein is highly protein dependent . In the current study, the effects of aprotic solvents on the charging and dimer dissociation of apo‐SOD1 are shown in Figures D,E and S1 and S2.…”

“…The bimodal effect of DMSO on protein charging has been well documented, and its effect on the structure of protein is highly protein dependent. 16,30,31 In the current study, the effects of aprotic solvents on the charging and dimer dissociation of apo-SOD1 are shown in Figures 2D,E and S1 and S2. With DMF as an example, the ESI mass spectra of apo-SOD1 with 0% to 20% DMF were obtained, and mass spectra with 0%, 1%, and 20%…”

“…CIU fingerprints show the conformational changes in proteins and the transition between distinct intermediates of proteins. 14,15 Some researchers have investigated the effects of dimethyl sulfoxide (DMSO) on protein-protein and protein-ligand interactions by native MS. [16][17][18][19] They reported that DMSO causes the compaction of protein structure and reduces the charge at low concentrations, but increases the charge at high concentrations. 20,21 However, the effects of aprotic solvents on protein stability were rarely evaluated by CID and CIU methods.…”

Electrochemical characterization of natural organic matter by direct voltammetry in an aprotic solvent

“…[126][127][128] DMSO has also been used as a (co)solvent for NOM, where it has been found to increase the quantity of humin recovered by the standard alkaline extraction method, 31 the diversity of organic matter obtained by alkaline extraction of soils and sediments, 129 and the quantity of hydrophobic moieties detected during structural characterization of NOM by high resolution NMR. 125 Analogous benets from the solvency of DMSO have been reported in studies of proteins, including reducing binding affinities of proteins, 130 protein unfolding, 131,132 DMSO affecting protein charge, 130 and aiding in electron transfer. [133][134][135] While mediators and aprotic solvents can greatly improve the electrode response of polyelectrolytes like proteins and NOM, other advances in electrochemical methodology can also have signicant benets.…”