Native mass spectra and IM data were processed in Mass-Lynx v4.2 (Waters Corp.), and deconvoluted using UniDec v4.3.0. 73 ECD data were processed using UNIFI (Waters Corp., UK). Raw spectra over the m/z range 200-8000 were deconvoluted for 30 iterations using the BayesSpray module operated in intact protein mode with a ToF resolution of 25,000. The resulting [M+H] + ion masses were then matched within 20 ppm error to theoretically generated b, y, c, and z fragment ions for bovine calmodulin (UniProt P62157) using ProSight Lite. Reported PTMs for bovine calmodulin, N-terminal methionine loss, N-terminal acetylation, and K 115 tri-methylation, were also applied to the sequence during matching.