In this contribution, we highlight the state of the art in the determination of structures with
ultrafast electrons and X‐rays. We provide our perspectives and reflections on the principles …

In a tour de force in this issue of PNAS, Bourgeois et al.(1) have used 2.2-ns x-ray pulses to
observe the motion of carbon monoxide (CO) through myoglobin (Mb) and the relaxation of …

The concept that proteins exist in numerous different conformations or conformational
substates, described by an energy landscape, is now accepted, but the dynamics is …

The modern electron microscope, as a result of recent revolutionary developments and
many evolutionary ones, now yields a wealth of quantitative knowledge pertaining to …

Myoglobin (Mb) is perhaps the most studied protein, experimentally and theoretically.
Despite the wealth of known details regarding the gas migration processes inside Mb, there …

Macromolecular crystallography has historically provided the atomic structures of proteins
fundamental to cellular functions. However, the advent of cryo-electron microscopy for …

BioCARS, a NIH-supported national user facility for macromolecular time-resolved X-ray
crystallography at the Advanced Photon Source (APS), has recently completed …

A chopper system for time resolved pump-probe experiments with x-ray beams from a
synchrotron is described. The system has three parts: a water-cooled heatload chopper, a …

Neuroglobin, a recently discovered globin predominantly expressed in neuronal tissue of
vertebrates, binds small, gaseous ligands at the sixth coordination position of the heme iron …

A detailed mechanistic understanding of how a protein functions requires knowledge not
only of its static structure, but also how its conformation evolves as it executes its function …