Single Protein Complexes Isomerization and Conformational Dynamics Using Trapped Ion Mobility Spectrometry: From MS to Seconds

Abstract

In the present work, examples of protein and peptide complexes conformational dynamics, from the solvent state distribution to the gas-phase “de-solvated” state distribution, are characterized for traditionally considered “unstructured” complexes. Conformational motifs and isomerization/conformational dynamics are identified and isomerization kinetics in the ms to few seconds timescale are measured for single molecules using a trapped ion mobility spectrometer - mass spectrometer (TIMS-MS). Theoretical calculations are used to simulate the experimental “TIMS box” single molecule -neutral bath gas phase dynamics and candidate structures are proposed for each conformational state. It is found that, side chain and backbone structural changes are the main motifs governing the conformational inter-conversion processes in the ms-s time scale. Examples will be shown for the case of folded/unfolded protein complexes and DNA-binding proteins.View Large Image | View Hi-Res Image | Download PowerPoint Slide