Elucidation of the initial step of oligonucleotide fragmentation in matrix-assisted laser desorption/ionization using modified nucleic acids.
To probe the mechanism of gas-phase oligonucleotide ion fragmentation, modified oligonucleotides were studied using matrix-assisted laser desorption/ionization. The oligonucleotides were of the form 5'-TTTTXTTTTT, where X was a modified nucleotide. Modifications included substitution of hydroxy, methoxy, amino, and allyl groups at the 2'-position of the deoxyribose. The modified ribose contained adenine, guanine, cytosine, or uracil bases. For comparison, we studied oligomers where X was an unmodified adenosine, guanosine, cytidine, thymidine, or uridine deoxyribonucleotide. We found a very strong dependence of the matrix-to-analyte ratio on fragmentation for these oligomers. Analysis of these modifications suggests that the initial fragmentation step in MALDI-MS involves a two-step (E1) elimination of the base.
Christian
N P
NP
Department of Chemistry, Indiana University, Bloomington 47505-7102, USA.
Reilly
J P
JP
Mokler
V R
VR
Wincott
F E
FE
Ellington
A D
AD
D000498:Allyl Compounds / Q000032:analysis; D009696:Nucleic Acids / Q000032:analysis*; D009841:Oligonucleotides / Q000032:analysis*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D000498:Allyl Compounds; D009696:Nucleic Acids; D009841:Oligonucleotides