Ultrafast myoglobin structural dynamics observed with an X-ray free-electron laser

Nat Commun. 2015 Apr 2;6:6772. doi: 10.1038/ncomms7772.

Abstract

Light absorption can trigger biologically relevant protein conformational changes. The light-induced structural rearrangement at the level of a photoexcited chromophore is known to occur in the femtosecond timescale and is expected to propagate through the protein as a quake-like intramolecular motion. Here we report direct experimental evidence of such 'proteinquake' observed in myoglobin through femtosecond X-ray solution scattering measurements performed at the Linac Coherent Light Source X-ray free-electron laser. An ultrafast increase of myoglobin radius of gyration occurs within 1 picosecond and is followed by a delayed protein expansion. As the system approaches equilibrium it undergoes damped oscillations with a ~3.6-picosecond time period. Our results unambiguously show how initially localized chemical changes can propagate at the level of the global protein conformation in the picosecond timescale.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Crystallography, X-Ray*
  • Horses
  • Lasers
  • Light*
  • Molecular Dynamics Simulation*
  • Myoglobin / chemistry*
  • Photolysis
  • Protein Conformation
  • Time Factors

Substances

  • Myoglobin
  • carboxymyoglobin