Abstract

Observing ultrafast myoglobin dynamics The oxygen-storage protein myoglobin was the first to have its three-dimensional structure determined and remains a workhorse for understanding how protein structure relates to function. Barends et al. used x-ray free-electron lasers with femtosecond short pulses to directly observe motions that occur within half a picosecond of CO dissociation (see the Perspective by Neutze). Combining the experiments with simulations shows that ultrafast motions of the heme couple to subpicosecond protein motions, which in turn couple to large-scale motions. Science , this issue p. 445 , see also p. 381