Flexible membrane proteins: functional dynamics captured by mass spectrometry.

Membrane proteins are flexible molecular machines, responsible for the exchange of molecules in and out of the cell, which have evolved to perform specific and complex tasks with great efficiency. Obtaining accurate descriptions of their dynamics in the context of their function represents a major challenge for structural biology. Here we chart recent developments in mass spectrometry designed to characterize changes in the dynamics of membrane proteins in response to ligand binding or post-translational modifications. We focus on cooperative movements and structural changes across a range of timescales, from milliseconds to minutes, and highlight the contributions of mass spectrometry to our understanding of molecular mechanisms of diverse transmembrane processes.