Predavanje prof. dr. Henryja Chapmana
Institut “Jožef Stefan”, Ljubljana, Slovenija, Odsek za biokemijo, molekularno in strukturno biologijo vabi na predavanje
v sredo, 26. oktobra 2016 ob 15h v Veliki predavalnici Instituta »Jožef Stefan«
Macromolecular Diffractive Imaging using Disordered Crystals
X-ray crystallography suffers from the well-known phase problem. This means that it is not possible to reconstruct an image of a molecule from its crystal diffraction pattern of Bragg peaks without additional knowledge or assumptions about the structure. The continuous diffraction from a single molecule contains vastly more information than from the crystal, overcoming the phase problem, but such diffraction is extremely weak. We have demonstrated a new method to record “single molecule” diffraction and obtain molecular images. The trick is to place many oriented molecules into the focused X-ray beam, which we do with a disordered crystal. Our method thus utilises commonly-occurring crystals that are usually not considered useful for measurement, overcoming a key bottleneck in structure determination. We demonstrate this technique by reconstructing images of photosystem II complexes at 3.5 Å resolution.
Note about the speaker. Henry Chapman is head of Coherent X-Ray Imaging division at the Center for Free Electron Laser Science at DESY and a professor of physics at the University of Hamburg. His work exploits the tremendous new capabilities of X-ray free-electron lasers, which deliver X-ray pulses that are a billion times more intense than synchrotron radiation, to determine the structure and dynamics of complex materials including macromolecules. He supervised the landmark experiments at FLASH (DESY) and the LCLS (SLAC) that demonstrated the possibility to “outrun” radiation damage with fast pulses and obtain atomic-resolution images from room temperature protein nanocrystals.
prof. dr. Dušan Turk