Abstract : We report time-resolved X-ray absorption measurements after photolysis of carbonmonoxy myoglobin performed at the LCLS X-ray free electron laser with nearly 100 fs (FWHM) time resolution. Data at the Fe K-edge reveal that the photoinduced structural changes at the heme occur in two steps, with a faster (∼70 fs) relaxation preceding a slower (∼400 fs) one. We tentatively attribute the first relaxation to a structural rearrangement induced by photolysis involving essentially only the heme chromophore and the second relaxation to a residual Fe motion out of the heme plane that is coupled to the displacement of myoglobin F-helix
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Submitted on : Monday, June 29, 2015 - 4:10:21 PM Last modification on : Tuesday, January 12, 2021 - 4:41:53 PM Long-term archiving on: : Wednesday, September 16, 2015 - 6:26:44 AM
M. Levantino, H. T. Lemke, Giorgio Schirò, M. Glownia, A. Cupane, et al.. Observing heme doming in myoglobin with femtosecond X-ray absorption spectroscopya). Structural Dynamics, 2015, 2 (4), pp.041713. ⟨10.1063/1.4921907⟩. ⟨hal-01168333⟩