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

• Published in: Journal of the American Chemical Society Vol. 115; no. 13; pp. 5869 - 5870
• Main Authors: Light-Wahl, K. J, Winger, B. E, Smith, R. D
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01-06-1993
• Subjects: 400102 - Chemical & Spectral Procedures; 400201 - Chemical & Physicochemical Properties; 550200 - Biochemistry; AGGLUTININS; Analytical, structural and metabolic biochemistry; ANTIBODIES; BASIC BIOLOGICAL SCIENCES; Biological and medical sciences; BIOLOGICAL MATERIALS; BLOOD VESSELS; BODY; CAPILLARIES; CARDIOVASCULAR SYSTEM; CONCANAVALIN A; DIMERS; Fundamental and applied biological sciences. Psychology; Glycoproteins; HEMAGGLUTININS; INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; IONIZATION; LECTINS; MASS SPECTROSCOPY; MATERIALS; ORGANS; Proteins; SPECTROSCOPY; Lectin; Electric field; Spraying; Glycoproteins; Concanavalin A; Mass spectrometry; Electrospray; Structural analysis
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/ja00066a083

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.