The use of short pulses of extremely bright synchrotron X-rays has opened up a new world. In Japan, Dr. S. Adachi (KEK, Tsukuba Japan) and his colleagues recently succeeded in recording movies during changes in the molecule structures of myoglobin. The samples used are frozen myoglobin crystals that had CO (carbon monoxide) stored inside before the start of the experiments. Even at 100K, irradiating pulsed laser light gave the trigger for the migration of CO molecules. To see changes in atomic scale, time-resolved X-ray diffraction measurements were performed. The obtained movie tells us that the CO molecules penetrate into a number of cavities in the crystal and even expand their size. The research group has obtained an important result suggesting some self-opening mechanism in the ligand migration channel. For more information, see the paper, "Visualizing breathing motion of internal cavities in concert with ligand migration in myoglobin", A. Tomita et al., Proceedings of National Academy of Science, 106, 2612-2616 (2009) Published online before print February 9, 2009, doi: 10.1073/pnas.0807774106
