Analysis of modified oligonucleotides by matrix-assisted laser desorption/ionization Fourier transform mass spectrometry
- Bowdoin College, Brunswick, ME (United States)
- Oak Ridge National Lab., TN (United States)
Matrix-assisted laser desorption/ionization (MALDI) Fourier transform ion cyclotron resonance mass spectrometry (FTMS) has been applied to the structural characterization of modified oligodeoxyribonucleotide 4-, 6-, and 11-mers. Each oligonucleotide contained one modified base, either an O{sup 6}-methyl-substituted guanine, an N{sup 6}-(10R)-trans-opened benzo[{alpha}]pyrenediol epoxide adduct of adenine, or an N{sup 2}(R)-styrene oxide adduct of guanine. For the 4- and 6-mers, the oligonucleotide sequence could be obtained from the direct anthranilic/nicotinic acid or 2,5-dihydrobenzoic acid spectra. Sequence information was also obtained by inserting a time delay between the laser desorption event and ion detection to permit metastable decomposition. For the 11-mers, high-mass sequence ions were not detected. In the positive ion mode, modified base fragment ions were observed when DHBA was used, and these fragments were examined using accurate mass measurements, collisionally induced dissociations, and ion-molecule reactions to characterize the modified base. MALDI-FTMS signals from one sample application can be used for the measurement of hundreds of spectra. The direct MALDI-FT mass spectra show matrix-dependent, structurally informative fragments, and CID experiments can be implemented using low-picomole sample quantities. 19 refs., 7 figs.
- DOE Contract Number:
- AC05-84OR21400; AC05-76OR00033
- OSTI ID:
- 105283
- Journal Information:
- Analytical Chemistry (Washington), Journal Name: Analytical Chemistry (Washington) Journal Issue: 17 Vol. 67; ISSN ANCHAM; ISSN 0003-2700
- Country of Publication:
- United States
- Language:
- English
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