Kb. Green-church et al., Gas-phase hydrogen/deuterium exchange of positively charged mononucleotides by use of Fourier-transform ion cyclotron resonance mass spectrometry, J AM SOC M, 12(3), 2001, pp. 268-277
Citations number
35
Categorie Soggetti
Spectroscopy /Instrumentation/Analytical Sciences
Journal title
JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY
The gas-phase structures of protonated (deoxy)nucleaside-5' and 3'-monophos
phates (mono-nueleotides) have been examined by the use of gas-phase hydrog
en/deuterium (H/D) exchange and high-field Fourier-transform ion cyclotron
resonance mass spectrometry. These nucleotides were reacted with three diff
erent deuterating reagents: ND3, D2O, and D2S, of which ND, was the most ef
fective. All mononucleotides fully exchanged their labile hydrogen for deut
erium with ND3 with the exception of deoxycytidine-3' monophosphate, deoxya
denosined5'-monophosphate, adenosine-5'-monophosphate, and adenosine3'-mono
phosphate. Semiempirical calculations demonstrate the presence of hydrogen
bonding upon protonation of the purine mononucleotides which may lead to in
complete H/D exchange. H/D exchange rates differed between the deoxymononuc
leotides and the ribomononucleotides, suggesting that the 2'-OH group plays
an important role in the exchange process. Reactions of nucleosides and mo
nonucleotides with D2O demonstrate that a structure-specific long-lived ion
-molecule complex between D2O and the mononucleotide involving the phosphat
e group is necessary for exchange to overcome the high-energy activation ba
rrier. in contrast, a structure-specific long-lived ion-molecule complex be
tween the mononucleotides and ND3 is not required for exchange to occur. (C
) 2001 American Society for Mass Spectrometry.