Membrane Proteins Have Distinct Fast Internal Motion and Residual Conformational Entropy Academic Article uri icon


  • The internal motions of integral membrane proteins have largely eluded comprehensive experimental characterization. Here the fast side-chain dynamics of the α-helical sensory rhodopsin II and the β-barrel outer membrane protein W have been investigated in lipid bilayers and detergent micelles by solution NMR relaxation techniques. Despite their differing topologies, both proteins have a similar distribution of methyl-bearing side-chain motion that is largely independent of membrane mimetic. The methyl-bearing side chains of both proteins are, on average, more dynamic in the ps-ns timescale than any soluble protein characterized to date. Accordingly, both proteins retain an extraordinary residual conformational entropy in the folded state, which provides a counterbalance to the absence of the hydrophobic effect. Furthermore, the high conformational entropy could greatly influence the thermodynamics underlying membrane-protein functions, including ligand binding, allostery, and signaling.

altmetric score

  • 12.4

author list (cited authors)

  • O'Brien, E. S., Fuglestad, B., Lessen, H. J., Stetz, M. A., Lin, D. W., Marques, B. S., ... Wand, A. J.

citation count

  • 7

publication date

  • April 2020