1. Nucleic Acid Fragmentation from Gas-Phase Ion-Electron Reactions
Kristina Håkansson, Department of Chemistry, University of Michigan,
Ann Arbor,
% deuterium
Nucleic acid higher order structure is critical for their biological function, e.g., catalysis and molecular recognition. Solution-phase hydrogen/ deuterium exchange (HDX) combined with mass spectrometry is commonly used for high sensitivity protein structure analysis. However, that approach is not suitable for nucleic acid structural determination due to the high opening rates (~ms) of Watson-Crick base pairs. Gas-phase HDX has been proposed as an alternative strategy. The Håkansson lab has implemented high pressure gas-phase HDX in a hybrid quadrupole-Fourier transform ion cyclotron resonance (Q-FT-ICR) mass spectrometer and shown that exchange rates for DNA and RNA hairpin structures correlate with their predicted solution-phase stabilities (due to different loop sizes and/or stem lengths). 3’ T C A 5’ G 3’ T C A G 5’
DG = kcal/mol
DG = kcal/mol
Deuterium exchange rates observed for isomeric DNA
15-mers upon storage in D2S vapor inside a hexapole
of a Q-FT-ICR mass spectrometer.