Macromolecular crystallography determines the atomic structure of biological macromolecules (mostly proteins and DNA) and their complexes by diffracting X-rays through a crystal grown from the macromolecule under study.
In contrast to synchrotrons, laboratory X-ray sources produce radiation at lower flux. Without dark current and readout noise, Dectris’ EIGER and PILATUS detectors can make arbitrary extensions of exposure time possible. Data quality at short exposure times — or finely sliced data collection — benefits from the absence of readout noise. Consequently, every crystal, no matter how weakly diffracting, can be measured at the laboratory X-ray source. Promising crystals for synchrotron experiments can be identified with confidence.
Most laboratory X-ray sources produce photons at 8.0 keV. At this energy level, sulfur atoms in most proteins produce weak anomalous signals that are often sufficient for experimental phasing. The high data quality obtained with EIGER and PILATUS detectors makes it possible to determine novel structures in the laboratory, without resorting to time-consuming work at a synchrotron.
Now, macromolecular crystallographers can obtain superb data at short acquisition times in their home laboratories.