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Interaction of first row transition metals with α1-3, α1-6 mannotriose and conserved trimannosyl core oligosaccharides: A comparative electrospray ionization study of doubly and singly charged complexes

1997; American Chemical Society; Volume: 8; Issue: 1 Linguagem: Inglês

10.1016/s1044-0305(97)82229-5

1879-1123

Emily M. Sible, Steven P. Brimmer, Julie A. Leary,

Environmental Chemistry and Analysis

Electrospray ionization and tandem mass spectrometry were used in the analysis of metalcoordinated oligosaccharides. Four transition metal ions, Cu2+, Mn2+, Co2+, and Zn2+, and the alkaline earth metal ion Ca2+, were each coordinated to the trimer α1–3, α1–6 mannotriose and the pentamer conserved trimannosyl core (mannotriosyl-chitobiose). Instrumental and concentration ratio optimization studies were carried out to determine the best conditions for producing the [M + Met]2+, [M + MetCl]+, and [M + Met − H]+ ions (Met = metal dication). These precursors were then subjected to tandem mass spectrometry (MS/MS) analysis and compared. Both the ionic radii and efficacy of ligand coordination were observed as important criteria for producing the precursor ions. Tandem mass spectra for the Cu2+- and Zn2+-coordinated species did not produce significant structural information about either the trimer or the pentamer. Although tandem mass spectra for the Ca2+-, Co2+-, and Mn2+-coordinated trimer were very similar, those of the pentamer were not. MS/MS of the Co2+-coordinated pentamer was the most unique and exhibited very different dissociation pathways.