Electron Capture Dissociation of Complexes of Diacylglycerophosphocholine and Divalent Metal Ions: Competition Between Charge Reduction and Radical Induced Phospholipid Fragmentation

Abstract

Divalent metal complexes of phosphocholines, [MetalII(L)n]2+ (where Metal = Cu2+, Co2+, Mg2+, and Ca2+, L = 1,2-dihexanoyl-sn-glycero-3-phosphocholine [6:0/6:0GPCho] and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine [16:0/18:1GPCho] and n = 2-5), were formed upon electrospray ionization mass spectrometry (ESI/MS) of 8 mM solution of phosphocholine (L) with 4 mM metal salt (Metal). The electron capture dissociation (ECD) reactions of these [MetalII(L)n]2+ complexes were examined via Fourier-transform ion-cyclotron resonance mass spectrometry. A rich and complex chemistry was observed, including charge reduction and fragmentation involving losses of a methyl radical, trimethylamine, and the..