SID-IM
Ion mobility (IM) is a gas-phase separation technique that separates ions based on their charge, size, and shape. In our lab, we couple IM to surface-induced dissociation (SID)1–4 to increase understanding about protein complex structure and subunit connectivity. IM can separate the overlapped protein complex precursor and subunit products, which improves post-SID data interpretation and protein complex characterization (Figure 1.). Additionally, with IM, we are able to perform surface-induced unfolding (SIU) to study the protein complex disorder by applying a range of SID voltages, recording the shift of the arrival time or collision cross section (CCS), and generating the SIU fingerprint (Figure 2.).
Figure 1. Top) SID spectrum of the 11-mer holoTRAP; Bottom) SID Mobiligram of the 11-mer holoTRAP
Figure 2. SIU fingerprint of 11+ homotetramer streptavidin
References
(1) Snyder, D. T.; Jones, B. J.; Lin, Y.-F.; Cooper-Shepherd, D. A.; Hewitt, D.; Wildgoose, J.; Brown, J. M.; Langridge, J. I.; Wysocki, V. H. Surface-Induced Dissociation of Protein Complexes on a Cyclic Ion Mobility Spectrometer. Analyst 2021, 146 (22), 6861–6873. https://doi.org/10.1039/D1AN01407B.
(2) Zhou, M.; Huang, C.; Wysocki, V. H. Surface-Induced Dissociation of Ion Mobility-Separated Noncovalent Complexes in a Quadrupole/Time-of-Flight Mass Spectrometer. Anal. Chem. 2012, 84 (14), 6016–6023. https://doi.org/10.1021/ac300810u.
(3) Zhou, M.; Jones, C. M.; Wysocki, V. H. Dissecting the Large Noncovalent Protein Complex GroEL with Surface-Induced Dissociation and Ion Mobility–Mass Spectrometry. Anal. Chem. 2013, 85 (17), 8262–8267. https://doi.org/10.1021/ac401497c.
(4) Zhou, M.; Wysocki, V. H. Surface Induced Dissociation: Dissecting Noncovalent Protein Complexes in the Gas Phase. Acc. Chem. Res. 2014, 47 (4), 1010–1018. https://doi.org/10.1021/ar400223t.