European Journal of Mass Spectrometry - Abstract of Letter: Collision-induced dissociation of [metal(L)2]2+ complexes (metal = Cu, Ca and Mg) of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine allows distinction of the acyl groups at the sn1 and sn2 positions

Letter: Collision-induced dissociation of [metal(L)₂]²⁺ complexes (metal = Cu, Ca and Mg) of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine allows distinction of the acyl groups at the sn1 and sn2 positions

Patrick F. James,^a–c Matthew A. Perugini ^a,c and Richard A.J. O'Hair ^b–d,*
^aDepartment of Biochemistry and Molecular Biology, University of Melbourne, Victoria 3010, Australia
^bSchool of Chemistry, University of Melbourne, Victoria 3010, Australia. E-mail: rohair@unimelb.edu.au
^cBio21 Institute of Molecular Science and Biotechnology, The University of Melbourne, Victoria 3010, Australia
^dARC Centre of Excellence in Free Radical Chemistry and Biotechnology

The collision induced dissociation (CID) spectra of the divalent metal complexes of 1-palmitoyl-2-oleoyl- sn-glycero-3-phosphocholine, [Metal^lI(L)₂]²⁺ (where metal = Cu²⁺, Mg²⁺ and Ca²⁺, L = [16:0/18:1GPCho]), formed by electrospray ionization, reveal interesting metal dependant fragmentation chemistry. Six main classes of reaction are observed corresponding to: two competing carboxylate abstraction pathways (from the sn1 and sn2 positions); phosphate abstraction; competing losses of the two different carboxylic acids from the sn1 and sn2 positions; loss of a protonated ligand, [L + H]⁺. The relative ratios of the competing carboxylate abstraction reactions are dependant on the metal, with the Cu and Ca complexes favouring the abstraction of the larger carboxylate (18:1) and the Mg complex favoring the abstraction of the smaller carboxylate (16:0).