Intérêt de la spectrométrie de mobilité ionique pour l'étude de la conformation et des assemblages non-covalents de biomolécules

This paper gives an overview of experimental and theoretical aspects of the ion mobility spectrometry technique coupled to mass spectrometry. These aspects are illustrated by a recent study on the conformation of a DNA sequence capable of forming intramolecular G-quadruplex folds. This sequence is found in the promoter of the gene coding for the c-Myc protein. The comparison between experimental collision cross sections determined by ion mobility spectrometry and theoretical cross sections calculated for several model structures allows
demonstrating that ions of low charge states have conserved the G-quadruplex parallel fold that was present in solution. Mass spectrometry also revealed the presence of a dimer, which conformation was interpreted using ion mobility : this structure consists of two parallel monomers stacked with each other.