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In situ diffraction data collection using crystallization plates has been utilized for macromolecules to evaluate crystal quality without requiring additional sample treatment such as cryocooling. Although it is difficult to collect complete data sets using this technique due to the mechanical limitation of crystal rotation, recent advances in methods for data collection from multiple crystals have overcome this issue. At SPring‐8, an in situ diffraction measurement system was constructed consisting of a goniometer for a plate, an articulated robot and plate storage. Using this system, complete data sets were obtained utilizing the small‐wedge measurement method. Combining this system with an acoustic liquid handler to prepare protein–ligand complex crystals by applying fragment compounds to trypsin crystals for in situ soaking, binding was confirmed for seven out of eight compounds. These results show that the system functioned properly to collect complete data for structural analysis and to expand the capability for ligand screening in combination with a liquid dispenser. [ABSTRACT FROM AUTHOR]

The characterization of crystal defects induced by irradiation, such as X‐rays, charged particles and neutrons, is important for understanding radiation damage and the associated generation of defects. Radiation damage to protein crystals has been measured using various methods. Until now, these methods have focused on decreased diffraction intensity, volume expansion of unit cells and specific damage to side chains. Here, the direct observation of specific crystal defects, such as dislocations, induced by X‐ray irradiation of protein crystals at room temperature is reported. Dislocations are induced even by low absorbed doses of X‐ray irradiation. This study revealed that for the same total absorbed dose, the formation of defects appears to critically depend on the dose rate. The relationship between dislocation energy and dose energy was analyzed based on dislocation theory associated with elasticity theory for crystalline materials. This demonstration of the crystal defects induced by X‐ray irradiation could help to understand the underlying mechanisms of X‐ray‐induced radiation damage. [ABSTRACT FROM AUTHOR]

Intense micro‐focus X‐ray beamlines available at synchrotron facilities have achieved high‐quality data collection even from the microcrystals of membrane proteins. The automatic data collection system developed at SPring‐8, named ZOO, has contributed to many structure determinations of membrane proteins using small‐wedge synchrotron crystallography (SWSX) datasets. The 'small‐wedge' (5–20°) datasets are collected from multiple crystals and then merged to obtain the final structure factors. To our knowledge, no systematic investigation on the dose dependence of data accuracy has so far been reported for SWSX, which is between 'serial crystallography' and 'rotation crystallography'. Thus, herein, we investigated the optimal dose conditions for experimental phasing with SWSX. Phase determination using anomalous scattering signals was found to be more difficult at higher doses. Furthermore, merging more homogeneous datasets grouped by hierarchical clustering with controlled doses mildly reduced the negative factors in data collection, such as 'lack of signal' and 'radiation damage'. In turn, as more datasets were merged, more probable phases could be obtained across a wider range of doses. Therefore, our findings show that it is essential to choose a lower dose than 10 MGy for de novo structure determination by SWSX. In particular, data collection using a dose of 5 MGy proved to be optimal in balancing the amount of signal available while reducing the amount of damage as much as possible. [ABSTRACT FROM AUTHOR]

Cryocrystallography is a technique that is used more often than room‐temperature data collection in macromolecular crystallography. One of its advantages is the significant reduction in radiation damage, which is especially useful in synchrotron experiments. Another advantage is that cryopreservation provides simple storage of crystals and easy transportation to a synchrotron. However, this technique sometimes results in the undesirable adhesion of frost to mounted crystals. The frost produces noisy diffraction images and reduces the optical visibility of crystals, which is crucial for aligning the crystal position with the incident X‐ray position. To resolve these issues, a computer‐controlled device has been developed that drizzles liquid nitrogen over a crystal to remove frost. It was confirmed that the device works properly, reduces noise from ice rings in diffraction images and enables the centering of crystals with low visibility owing to frost adhesion. [ABSTRACT FROM AUTHOR]

In this study, the magnetically oriented microcrystal suspension (MOMS) method is combined with the shutterless continuous rotation method. In the MOMS method, the suspension has to be rotated to maintain the three-dimensional orientation of microcrystals. This means that it is compatible with the continuous rotation method, which also utilizes sample rotation. The time constants of the two methods should match to allow their successful combination. The conditions required for the MOMS method for combination with the continuous rotation method are investigated. Experiments are performed with a complementary metal-oxide semiconductor (CMOS) detector and the restriction imposed on the time constant for the MOMS method by the continuous rotation method is examined. The combination of these two methods is a promising approach for realizing the structure analyses of biomolecules from their microcrystalline powders. [ABSTRACT FROM AUTHOR]

A figure in the article by Baba et al.[(2021), J. Synchrotron Rad.28, 1284–1295] is corrected. [ABSTRACT FROM AUTHOR]