Professor A. Cupane (University of Palermo, Italy) and his colleagues at the European Synchrotron Radiation Facility (ESRF) recently established a method for structural dynamics. The technique uses wide-angle X-ray scattering and images proteins in their natural, fast-moving state. The research group succeeded in capturing the tertiary and quaternary conformational changes of human hemoglobin in close to physiological conditions triggered by laser-induced ligand photolysis. The time resolution of the observation is in the order of nsec. The whole process lasts 3 μsec, and the molecule changes from a "relaxed" form that can bond to oxygen, to a "tense" form that squeezes out the oxygen. They also reported data on optically induced tertiary relaxations of myoglobin and refolding of cytochrome c. For more information, see the paper, "Tracking the structural dynamics of proteins in solution using time-resolved wide-angle X-ray scattering", M. Cammarata et al., Nature Methods, published online, 21 September 2008, doi:10.1038/nmeth.1255
