Low-energy collisionally activated dissociation of pentose–borate complexes

Pentose–borate 1:1 complexes were generated in the ESI source of a triple quadrupole and ion trap mass spectrometer by electrospray ionization of Na2B4O7 and pentose (arabinose, lyxose, ribose, xylose) 2:1 solution in CH3CN/H2O. The study of their low-energy collisionally activated dissociation (CAD) demonstrated that ribose and lyxose are preferentially complexed at the C2–C3cis-diol function whereas arabinose and xylose are esterified at the C1–C2 hydroxyl groups. No evidence was found of the stronger affinity for ribose to borate. The ribose probiotic rule can be explained by considering its peculiar capability, among the investigated pentoses, to almost totally complex the borate anion at the C2–C3 hydroxyl group, thus enabling the subsequent stages of nucleotide assembly, such as phosphorylation and linkage to the nucleobases.Finally, the differences observed in the pentose–borate complex CAD spectra can be used for the mass spectrometric discrimination of isomeric pentoses in complex mixtures.

The borate–pentose complexation was studied by mass-spectrometric techniques. Ribose and lyxose are preferentially complexed at the C2–C3cis-diol function whereas arabinose and xylose at the C1–C2.Figure optionsDownload as PowerPoint slide