ESI-MS/MS for the differentiation of diastereomeric pyrimidine glycols in mononucleosides.
Pyrimidine glycols, or 5,6-dihydroxy-5,6-dihydropyrimidines, are primary lesions in DNA induced by reactive oxygen species. In this article, we report the preparation and tandem mass spectrometry (MS/MS) characterization of the two cis diastereomers of the glycol lesions of 2'-deoxyuridine, 5-methyl-2'-deoxycytidine, and thymidine. Our results show that collisional activation of the [M + Na]+ ions of all the three pairs of cis isomers and that of the [M + H]+ ions of the 2'-deoxyuridine glycols and 5-methyl-2'-deoxycytidine glycols give a facile loss of a water molecule. Interestingly, the water loss occurs more readily for the 6S isomer than for the 6R isomer. Likewise, product ion spectra of the [M - H]- ions of the two cis isomers of the 2'-deoxyuridine glycols and thymidine glycols show more facile loss of water for the 6S isomer than for the 6R isomer. MS/MS acquired at different collisional energies gave similar results, which establishes the reproducibility of spectra.
Wang
Yinsheng
Y
Department of Chemistry, University of California at Riverside, 92521-0403, USA. yinsheng.wang@ucr.edu
Vivekananda
Shetty
S
Zhang
Kangling
K
D004249:DNA Damage; D006018:Glycols / Q000032:analysis* / Q000737:chemistry; D009705:Nucleosides / Q000032:analysis / Q000737:chemistry; D011743:Pyrimidines / Q000032:analysis* / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D013237:Stereoisomerism
D006018:Glycols; D009705:Nucleosides; D011743:Pyrimidines