Native electrospray and electron-capture dissociation in FTICR mass spectrometry provide top-down sequencing of a protein component in an intact protein assembly
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- Zhang, H., Cui, W., Wen, J. et al. J Am Soc Mass Spectrom (2010) 21: 1966. doi:10.1016/j.jasms.2010.08.006
The intact yeast alcohol dehydrogenase (ADH) tetramer of 147 kDa was introduced into a FTICR mass spectrometer by native electrospray. Electron capture dissociation of the entire 23+ to 27+ charge state distribution produced the expected charge-reduced ions and, more unexpectedly, 39 c-type peptide fragments that identified N-terminus acetylation and the first 55 amino acids. The results are in accord with the crystal structure of yeast ADH, which shows that the C-terminus is buried at the assembly interface, whereas the N-terminus is exposed, allowing ECD to occur. This remarkable observation shows promise that a top-down approach for intact protein assemblies will be effective for characterizing their components, inferring their interfaces, and obtaining both proteomics and structural biology information in one experiment.