Differentiation of 2 ';-O- and 3 ';-O-methylated ribonucleosides by tandem mass spectrometry

作者：Zhang Qingchun; Wang Yinsheng^*

来源：Journal of the American Society for Mass Spectrometry, 2006, 17(8): 1096-1099.

DOI：10.1016/j.jasms.2006.04.023

Recent studies revealed that the 3';-terminal nucleotides in plant microRNAs were methylated on the ribose at the 2'; or 3'; hydroxyl groups. Here we examined the fragmentation of the electrospray-produced [M + H](+) and [M - H](-) ions of 2';- and 3';-O-methylated ribonucleo-sides. It turned out that the predominant fragmentation pathway for the [M + H]+ ions of ribose-methylated nucleosides was the neutral loss of the methylated ribose, which made it impossible to distinguish 2';-O-methylation from 3';-O-methylation by positive-ion MS/MS. However, characteristic fragment ions, resulting from the cleavage through the ribose rings, Were produced for the [M - H](-) ions of each pair of ribose-methylated nucleosides. In this respect, the neutral loss of a 90-Da fragment (C3H6O3) was observed for 2';-O-methylated cytidine, guanosine and adenosine, but not for their 3';-O-methylated counterparts. On the other hand, the neutral loss of a 60-Da fragment (C2H4O2) was found for 3';-O-methyluridine, but not for 2';-O-methyluridine.

• 出版日期2006-8