Evaluation of crystal quality of thin protein crystals based on the dynamical theory of X-ray diffraction

Abstract

<jats:p>Knowledge of X-ray diffraction in macromolecular crystals is important for not only structural analysis of proteins but also diffraction physics. Dynamical diffraction provides evidence of perfect crystals. Until now, clear dynamical diffraction in protein crystals has only been observed in glucose isomerase crystals. We wondered whether there were other protein crystals with high quality that exhibit dynamical diffraction. Here we report the observation of dynamical diffraction in thin ferritin crystals by rocking-curve measurement and imaging techniques such as X-ray topography. It is generally known that in the case of thin crystals it is difficult to distinguish whether dynamical diffraction occurs from only rocking-curve profiles. Therefore, our results clarified that dynamical diffraction occurs in thin protein crystals because fringe contrasts similar to <jats:italic>Pendellösung</jats:italic> fringes were clearly observed in the X-ray topographic images. For macromolecular crystallography, it is hard to obtain large crystals because they are difficult to crystallize. For thin crystals, dynamical diffraction can be demonstrated by analysis of the equal-thickness fringes observed by X-ray topography.</jats:p>

Identification of grown-in dislocations in protein crystals by digital X-ray topography

“…1. In order to measure the X-ray topography, the crystals on the cover glass were sealed in acrylic cells, as has been reported previously Abe et al, 2020).…”

“…This indicates that protein crystals have poor crystallinity. On the other hand, dynamic diffraction for perfect crystals of biomacromolecules such as glucose isomerase and ferritin has recently been clearly observed and analysed by rocking-curve ISSN 1600-5767 # 2021 International Union of Crystallography measurements with X-ray topography (Suzuki et al, 2017;Abe et al, 2020). However, the origin of the perfection and imperfection has not been clarified yet.…”

Rocking-curve imaging of high-quality protein crystals by non-dispersive X-ray optics in the double-crystal configuration

“…Recently, we reported that glucose isomerase (GI) and ferritin crystals, which are protein crystals with large d spacing, ISSN 1600-5767 can be obtained at quite high quality (Suzuki et al, 2017;Abe et al, 2020). Perfection has been characterized by the observation and calculation of oscillatory profiles of rocking curves and fringe contrasts (i.e.…”

Control of strain in subgrains of protein crystals by the introduction of grown-in dislocations

“…Recently, clear equal-thickness fringes have also been observed for crystals of other proteins such as tetragonal HEW lysozyme (Koizumi et al, 2019) and ferritin (Abe et al, 2020). Therefore, control of the local strain in subgrains could be useful to enhance the resistance of various protein crystals to radiation damage.…”