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

• DOI: 10.1038/ncomms7772
• Publication Date: 2015-04-02T11:26:46Z
• Authors: Matteo Levantino; Giorgio Schirò; Henrik Till Lemke; Grazia Cottone; James Michael Glo...; Diling Zhu; Mathieu Chollet; Hyotcherl Ihee; Antonio Cupane; Marco Cammarata
• Keywords: Picosecond; Protein Dynamics

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 femtosecond timescale and expected propagate through as quake-like intramolecular motion. Here we report direct experimental evidence such ‘proteinquake’ observed myoglobin X-ray solution scattering measurements performed Linac Coherent Source free-electron laser. An ultrafast increase radius gyration occurs within 1 picosecond followed by delayed expansion. As system approaches equilibrium it undergoes damped oscillations with ~3.6-picosecond time period. Our results unambiguously show how initially localized chemical changes global conformation timescale.