Characterization of methylated and unmethlyated CpG-ODNs by electrospray ionization tandem mass spectrometry

Eur. J. Mass Spectrom. 11, 581–589 (2005)
DOI: 10.1255/ejms.774

Characterization of methylated and unmethlyated CpG-ODNs by electrospray ionization tandem mass spectrometry

Huimin Ma,^a,b Wenbing Zhang,^a,* Renfang Song,^a,b Huayong Chen,^a,b Guoying Sheng,^a Zhen Zhou^a and Jiamo Fu^a
^aState Key Laboratory of Organic Geochemistry, Guangzhou Research Center of Mass Spectrometry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China
^bGraduate school of the Chinese Academy of Science, Beijing, China

ABSTRACT:

Methylated and unmethylated CpG-ODNs at A-rich, C-rich, G-rich and T-rich conditions were characterized by electrospray ionization tandem mass spectrometry (ESI-MS/MS). The methylted site could be confirmed by comparison of the MS/MS spectra of methylated and unmethylated CpG-ODNs. The fragmentation patterns of the CpG-ODNs were not influenced by the presence of the methyl group but significant effects were observed for nucleobase identities and parent ion charges. The cleavage at guanine was the most facile while that at thymine was the least facile. With the increase of the parent ions charge states, the major dissociation behaviors changed from the middle to the 3′ and 5′ termini of the sequence.

Keywords: CpG-ODNs, methylation, oligonucleotides, electrospray ionization mass spectrometry

You can buy this paper on-line in PDF format; it costs only £11.75. Just click on the BUY on-line button. You can pay on-line through a secure server and get access immediately.