Linking molecular models with ion mobility experiments. Illustration with a rigid nucleic acid structure

Abstract

The preservation of molecular ion three dimensional conformations of electrospray formed ions is a question that many researchers have asked and that can now be answered using ion mobility coupled to mass spectrometry. Indeed, ion mobility has the ability to separate ions according to their size-to-charge ratios in the gas-phase. Size is related to the mass and to the three-dimensional shape of a molecule. Therefore, by hyphenating ion mobility to mass spectrometry (IM-MS), one can sort ions according to both mass and shape. The challenge is to decipher structural information from ion mobility experiments. In this tutorial special feature, Valerie Gabelica and co-workers clarify how to interpret experimental collision cross section measurements in terms of three-dimensional structure for ions larger than 100 atoms and how these can be compared to those calculated for modelling three-dimensional structures of the ion of interest. Dr. Gabelica is an Inserm Research Director at the Institut Européen de Chimie et Biologie (Université de Bordeaux, France). Her research interests are centered on the detection, quantification and characterization of all the assemblies and tridimensional structures formed by nucleic acids in solution, using tailor-made MS-based approaches.