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Observation of the multimeric forms of concanavalin A by electrospray ionization mass spectrometry

Journal Article · · Journal of the American Chemical Society; (United States)
DOI:https://doi.org/10.1021/ja00066a083· OSTI ID:5845175
; ;  [1]
  1. Pacific Northwest Lab., Richland, WA (United States)

In this communication, we report the successful ionization and dethection of the dimeric and tetrameric forms of concanavalin A (Con A) by ESI/MS. Concanavalin A, the jack bean lectin, has been the subject of many biochemical studies. Results show that self-association of Con A subunits to form dimers and tetramers can be observed upon transfer to the gas phase with ESI/MS and that careful choice of interface conditions is crucial for preserving these noncovalent associations, consistent with earlier reports for the analysis of noncovalent complexes. It is noteworthy that the average charge per monomer unit has the order monomer > dimer > tetramer, with a decrease of approximately two charges (per monomer unit) for the tetramer-to-dimer transition. An extended m/z range is useful for such studies since the tetrameric form of Con A is observed only beyond m/z 4000. Higher charge-statee ions for a given species are collisionally activated to a greater extent in the interface than lower charge-state ions of the same species, are less stable due to repulsive Coulombic forces, and thus are more likely to dissociate due to the same processes required to desolvate te lower charge-stat ions. 15 refs., 1 fig.

DOE Contract Number:
AC06-76RL01830
OSTI ID:
5845175
Journal Information:
Journal of the American Chemical Society; (United States), Journal Name: Journal of the American Chemical Society; (United States) Vol. 115:13; ISSN JACSAT; ISSN 0002-7863
Country of Publication:
United States
Language:
English