Controlled beam divergence on a laboratory diffractometer to improve spatial resolution of reflections for Era protein crystals from Staphylococcus aureus

Abstract

Obtaining spatial structures with high resolution by the XRD method is still associated with significant difficulties for laboratory single-crystal diffractometers incorporating modern confocal multilayer optics with high intensity and small X-ray beam diameter (≤ 100 μm). As the unit cell size increases, the distance between reflections in the diffraction pattern decreases, which leads to their overlapping. To minimize the overlap and separate reflections as distinct peaks, the distance from the crystal to the detector is traditionally increased. However, this approach is not always successful due to the divergence of the X-ray beam. A potential alternative solution is to optimize the beam divergence parameters in the optical device of the X-ray source. Using an Era protein crystal from Staphylococcus aureus with large unit cell parameters (a = b = 78.1(1) Å and c = 244.9(2) Å), a successful optimization of the X-ray beam divergence parameter selection for high-resolution XRD data acquisition was demonstrated.