The collision cross-section (Ω) of a protein or protein complex ion can be measured using traveling-wave (T-wave) ion mobility (IM) mass spectrometry and calibration with compounds of known Ω. Obtaining accurate T-wave Ω-values via calibration, especially for native-like protein ions, remains challenging. Using human insulin oligomer ions we show how to select appropriate calibration standards, find the optimal instrument settings, and validate the resulting T-wave Ω-values. We also probe subtle conformational differences between human insulin and insulin aspart, a fast-acting insulin analog.
These results are also useful for calibrating other ion mobility experiments, particularly for ions of smaller, native-like proteins and protein complexes. Those values have been added to our collision cross section database.
Traveling-wave ion mobility mass spectrometry of protein complexes: accurate calibrated collision cross-sections of human insulin oligomers Rune Salbo, Matthew F. Bush, Helle Naver, Iain Campuzano, Carol V. Robinson, Ingrid Pettersson, Thomas J. D. Jørgensen, Kim F. Haselmann. Rapid Commun. Mass Spectrom. 2012, 26, 1181–1193.
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