Macromolecular Diffractive Imaging using Disordered Crystals

Program Description

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 demonstrated this technique at LCLS by reconstructing images of photosystem II complexes at 3.5 Å resolution [1].

1. K. Ayyer et al. Nature 530, 202–206 (2016).