IUCrJ launches electron crystallography section

Negative linear compressibility at extreme pressure

Structural studies of chemical elements in extreme pressure conditions often lead to unpredictable and surprising results. At ultra-high pressure Yuan et al. [IUCrJ (2022), 9, 253–260] report a new crystal phase of selenium that exhibits negative linear compressibility.

Sifting fluctuation scattering from microtextured samples

As the relationship of texture and microtexture to fluctuation X-ray scattering (FXS) has been clarified in detail, key progress is expected in the exploitation of FXS-based structural investigation of matter exhibiting complex order.

MicroED: conception, practice and future opportunities

Microcrystal electron diffraction is described and put in the context of its origins in macromolecular crystallography.

Trends in coordination of rhenium organometallic complexes in the Protein Data Bank

This topical review is focused on the development of radiopharmaceuticals containing the radioisotopes of rhenium and technetium, and examines the occurrence of these transition-metal complexes in protein structures in the Worldwide Protein Data Bank. In summing up and looking forward, the authors ask what is the best way for this field to progress.

Crystallography relevant to Mars and Galilean icy moons: crystal behavior of kieserite-type monohydrate sulfates at extraterrestrial conditions down to 15 K

The low-temperature crystallography of kieserite-type monohydrate sulfates, relevant for Mars and Galilean icy moons, has been investigated down to 15 K, revealing a pronounced anisotropy of their thermal expansion behavior. The present results provide a reliable basis for the proper assignment of sulfate-related signals obtained from remote-sensing data from orbiters at celestial bodies.

Unsupervised learning approaches to characterizing heterogeneous samples using X-ray single-particle imaging

Two unsupervised machine learning approaches are presented to characterize structural variations in nanoparticle ensembles measured using X-ray single-particle imaging. The algorithms are applied to an experimental dataset where both discrete structural classes and continuous deformations caused by X-ray induced melting are classified.

Formation and stabilization mechanism of mesoscale clusters in solution

The mechanism for the formation and stability of nucleation precursors of mesoscale clusters is explored and previous work on clusters mainly consisted of phenomenological reports.

Qu­antitative analysis of the effect of radiation on mitochondria structure using coherent diffraction imaging with a clustering algorithm

A clustering algorithm based on deep learning is proposed to perform accurate image reconstruction from noisy coherent diffraction patterns. Structural changes in mitochondria induced by X-ray radiation damage are quantitatively characterized and analysed at the nanoscale with different radiation doses.

Preferred orientation and its effects on intensity-correlation measurements

The theory of preferred orientation in fluctuation scattering is developed and demonstrated in experimental studies of self-assembled lipid materials.

High-speed high-resolution data collection on a 200 keV cryo-TEM

This study explores parameters for high-speed, high-resolution, single-particle data collection using a 200 keV Talos Arctica equipped with a Gatan K3 DED. Near-atomic resolution electron microscopy maps were obtained from datasets collected as fast as 720 movies per hour.

Negative linear compressibility in Se at ultra-high pressure above 120 GPa

Structural evolutions of selenium on strong compression are still not fully understood, therefore in situ X-ray diffraction measurements up to 210 GPa were carried out. An anomalous negative linear expansion was observed at pressures from 120 to 148 GPa, accompanied by a new isostructural phase transition.

X-ray structure of the Rhodobacter sphaeroides reaction center with an M197 Phe→His substitution clarifies the properties of the mutant complex

Crystal structures of an F(M197)H mutant form of the photosynthetic reaction center obtained using different techniques clarify the optical and electrochemical properties of the primary electron donor and the increased resistance of this mutant complex to denaturation.

Static and dynamic components of Debye–Waller coefficients in the novel cubic polymorph of low-temperature disordered Cu₂ZnSnS₄

Disorder greatly affects transport properties, as observed for Cu₂ZnSnS₄. A novel cubic polymorph of Cu₂ZnSnS₄ is characterized, and cation disorder is observed in a static contribution to Debye–Waller coefficients.

Hirshfeld atom refinement based on projector augmented wave densities with periodic boundary conditions

Deriving the atomic form factors from Hirshfeld-partitioned periodic projector augmented wave calculations shows a great benefit for H-atom bond lengths and a smaller benefit for H-atom atomic displacement parameters.

Fragmentation and transferability in Hirshfeld atom refinement

Hirshfeld atom refinement (HAR) combined with fragmentation and atomic density transferability was tested on various systems, both polymeric and disordered. HAR was significantly faster with these adjustments, reducing computational time for larger systems with only a modest drop in accuracy.

Crystal structures of PigF, an O-methyltransferase involved in the prodigiosin synthetic pathway, reveal an induced-fit substrate-recognition mechanism

Crystal structures of apo and SAH-bound PigF were determined and structural analyses revealed an induced-fit substrate-recognition model.

An advanced workflow for single-particle imaging with the limited data at an X-ray free-electron laser. Corrigendum

An error in the article by Assalauova et al. [IUCrJ (2020), 7, 1102–1113] is corrected.