Investigating direct current potentials that affect native protein conformation during trapped ion mobility spectrometry –mass spectrometry

AbstractTrapped ion mobility spectrometry –time-of-flight mass spectrometry (TIMS-TOFMS) has emerged as a tool to study protein conformational states. In TIMS, gas-phase ions are guided across the IM stages by applying direct current (DC) potentials (D1–6), which, however, might induce changes in protein structures through collisional a ctivation. To define conditions for native protein analysis, we evaluated the influence of these DC potentials using the metalloenzyme bovine carbonic anhydrase (BCA) as primary test compound. The variation of DC potentials did not change BCA-ion charge and heme content but affected (relative) charg e-state intensities and adduct retention. Constructed extracted-ion mobilograms and corresponding collisional cross-section (CCS) profiles gave useful insights in (alterations of) protein conformational state. For BCA, the D3 and D6 potential (which are applied between the deflection transfer and fu nnel 1 [F1] and the accumulation exit and the start of the ramp, respectively) had most profound effects, showing multimodal CCS distributions at higher potentials indicating gradual unfolding. The other DC potentials only marginally altered the CCS profiles of BCA. To allow for more general conclus ions, five additional proteins of diverse molecular weight and conformational stability were analyzed, and for the main protein charge states, CCS profiles were constructed. Principal component analysis (PCA) of the obtained data showed that D1 and D3 ex...

Source: Journal of Mass Spectrometry - April 12, 2024 Category: Chemistry Authors: Robert L. C. Voeten, Hany A. Majeed, Tijmen S. Bos, Govert W. Somsen, Rob Haselberg Tags: RESEARCH ARTICLE Source Type: research