Structural motifs of DNA complexes in the gas phase

DNA duplexes are known to be quite stable in the condensed phase but recent mass spectrometry results have shown that DNA complexes are also stable (at least for a limited time) in the gas phase. However, very little is known about the overall shape of the complexes in a solvent-free environment and what factors influence that shape. In this article, we present recent ion mobility and molecular modeling results that address some issues concerning the gas-phase conformations of DNA duplexes. Examples include the effect of metal ions on Watson-Crick base pairing, investigating the onset of helicity in duplexes as a function of strand length, comparison of the stability of C·G and A·T base pairs, and examining the formation of quadruplex structures.