AXIS: a Lab-in-the-Loop machine learning approach for automated detection of macromolecular crystals

AXIS (AI-based Crystal Identification System) combines artificial intelligence with an iterative Lab-in-the-Loop approach for automated crystal detection. AXIS ensures high performance in crystal detection, requires small training datasets and facilitates rapid adaptation to local and changing conditions at any given facility.

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Probing laser-driven surface and subsurface dynamics via grazing-incidence XFEL scattering and diffraction

We demonstrate a grazing-incidence XFEL platform that simultaneously records time-resolved GISAXS and GID, enabling depth-selective probing of ultrafast surface and subsurface dynamics in a laser-irradiated gold film. The approach correlates nanoscale morphology evolution with lattice compression, melting and recrystallization, providing benchmarks for ultrafast laser–matter interaction models.

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Kinetic effects yield different results on the timescales of laboratory and synchrotron high-pressure experiments

Kinetic effects can be a critical factor in the study of high-pressure phase transitions. X-ray diffraction experiments on the timescales of the laboratory and the synchrotron can provide complementary results on such transformations.

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Enzyme therapy in a structural light

The paper by Gilski et al. in this issue [IUCrJ (2026), 13, 132–145] focuses on the stereochemical analysis of the catalytic mechanism of asparaginases with the aim of resolving key ambiguities in the mechanism. These enzymes have found truly remarkable therapeutic success in the treatment of childhood leukemias.

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Round robin on structure analysis from 3D electron diffraction data

This blind test uses three known samples to determine the accuracy limits of 3D electron diffraction and to assess various challenges. The study aims to evaluate how well different users with diverse experimental setups can perform tasks such as hydrogen-atom detection, mixed occupancy analysis and absolute structure determination. By comparing results across multiple participants and platforms, we can gauge the reliability of the method and identify potential areas for improvement in 3D electron diffraction techniques.

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Modelling of radiation damage and beam-induced heating of room-temperature samples at extremely high flux MX beamlines

Modelling of radiation damage and beam-induced heating at extremely high flux macromolecular crystallography beamlines is presented.

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Application of differential scanning fluorimetry to X-ray protein crystallography

Differential scanning fluorimetry (DSF) assesses protein thermal stability in solution using a standard real-time PCR instrument. Optimizing the protein buffer composition and crystallization conditions through DSF can significantly enhance crystal quality.

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Automated microbatch-under-oil phase diagrams to rationalize serial crystallography sample preparation

An automated, low-volume microbatch-under-oil crystallization approach is described that rapidly maps phase diagram boundaries. This approach rationalizes the production of microcrystal suspensions for serial crystallography by explicitly distinguishing metastable from nucleation zones, thereby replacing empirical trial and error with a quantitative guide to sample optimization.

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Catching new modulated high-pressure phases of δ-chlorpropamide: when the experimental setup matters

Commensurately and incommensurately modulated phases of chlorpropamide have been obtained for the first time on hydro­static compression of its δ polymorph.

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Stereochemical aspects of the nucleophilic attack in different classes of l-asparaginases

Stereochemical analysis based on the principle of structure correlations has been carried out to identify the primary nucleophile residue in each of the three classes of l-asparaginases and in a group of classless enzymes, helping to confirm their classification.

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AutoLEI: A step towards automatic 3D ED data processing

A user-friendly interface has been developed for XDS, enabling efficient real-time and batch processing of 3D ED data to accelerate structure determination.

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Phase transitions in rutile-related V0.92O2 synthesized at high pressures and tem­per­a­tures

Phase transitions in metastable rutile-related V0.92O2 were studied with single-crystal X-ray diffraction and measurements of electronic transport properties at extreme conditions. The high-tem­per­a­ture incommensurate phase was found to be insulating.

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AutoLEI: An XDS-based pipeline with graphical user interface for automated real-time and offline batch 3D ED/microED data processing

A pipeline with a graphical user interface for real-time and offline 3D ED/microED data processing by XDS was developed. The pipeline aims to improve efficiency, minimize redundant data processing work and provide users with real-time feedback during data collection.

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Crystal structure of di­acet­y­lene unveiled by X-ray and neutron diffraction, Raman spectroscopy and periodic DFT

The crystal structure and thermal expansion behaviour of di­acet­y­lene were determined via diffraction methods and supplemented by spectroscopic techniques. The similarities to the structure of acetylene and implications for Titan in situ exploration are discussed.

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Anisotropic diffraction of materials with fibre symmetry: application to chitin cuticle

A generalized diffraction model is presented for anisotropic nanomaterials with fibre symmetry, enabling the extraction of 3D orientation, strain and angular dispersion from wide-angle X-ray scattering patterns without sample rotation. Validated on chitinous Bouligand structures in shrimp cuticle, this framework allows robust multi-reflection analysis and is broadly applicable to complex biological and synthetic fibre-based materials.

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The relationship between the Ewald sphere and exit wave explored using focal series electron micrographs

The Ewald sphere is inherent in image formation in the electron microscope and must therefore be part of the reconstruction of cryoEM maps. This study examines linear image-formation theory to show how Ewald sphere information derives from focal series micrographs and relates to the exit wave. It concludes by suggesting the proper way to correct for the contrast transfer function for cryoEM reconstruction.

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Linear-scaling aspherical crystallographic refinement of proteins: a case study for crambin and rubredoxin

Linear-scaling fragment Hirshfeld atom refinement has been implemented in Olex2 within the NoSpherA2 interface, which also solved previous issues with hydrogen bonds. This allowed the refinement of two small proteins, crambin and rubredoxin (the latter including a metal site), with quantum mechanical aspherical atomic form factors.

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Obtaining single crystals containing cationic porphyrins from aqueous solutions: a systematic approach including nano-crystallization, organic modifiers and gel crystallization

A stepwise guide to the crystallization of charged molecules from aqueous solutions is presented.

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Structure of the bacteriophage PhiKZ non-virion RNA polymerase bound to a p119L open promoter analogue

Bacteriophage ΦKZ is a massive bacterial virus with potential as a therapy for Pseudomonas aeruginosa, which forms a bacteriophage nucleus in infected cells to exclude the host immune system, and transcribes its genes with its own, non-canonical multi-subunit RNA polymerase. The structure of this polymerase in the process of binding an analogue of its cognate promoter is resolved, revealing an unanticipated method of promoter consensus recognition involving the β-like, rather than the σ-factor-like subunit.

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Structural insights into the antiviral efficacy of AG7404 against human rhinovirus 3C proteases

This study presents the crystal structure of human rhinovirus (hRV)-B14 3C protease bound to AG7404, a broad-spectrum antiviral inhibitor, at a resolution of 2.11 Å. Antiviral assays and in silico studies provide structural insights into AG7404's efficacy and binding mechanism against hRV-B14, hRV-A16 and hRV-A21 3C proteases.

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Broadband high-resolution X-ray ptychography system spanning tender to hard X-ray regimes

An advanced X-ray ptychography system has been developed that facilitates nanoscale imaging across both tender and hard X-ray regions using a single optical setup.

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`Mix-it-up': accessible time-resolved cryo-EM on the millisecond timescale

The development of methods for low-cost time-resolved cryo-EM using an on-grid mixing strategy is described.

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Protein electrostatic potential Fourier maps calculated using the transferable aspherical atom model and the independent atom model across resolutions

Electrostatic potential maps of proteins are calculated at various resolutions using the transferable aspherical atom model (TAAM) to determine the relations between the electrostatic potential and resolution for different atom types.

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Testing the limits: serial crystallography using unpatterned fixed targets

The influence of the X-ray step size on radiation damage occurring in serial data collection from a metalloprotein using sheet-on-sheet fixed-target chips was investigated at fourth-generation synchrotron and XFEL beamlines.

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Unveiling the ambient-condition structure of Sr2FeIrO6: a triclinic phase through synchrotron-based X-ray techniques and high pressure

The room-temperature structure of Sr2FeIrO6, a double perovskite with notable magnetic and structural properties, has been debated extensively. Our high-resolution and high-pressure synchrotron-based powder X-ray diffraction findings provide compelling evidence to reconcile these divergent positions, laying groundwork for future research.

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New structural insights into Fe2P2O7 – unravelling an unresolved dispute and three reversible phase transitions

Thortveitite-related Fe2P2O7 shows three reversible phase transitions and has an incommensurately modulated crystal structure at room temperature.

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Unravelling venetoclax solvate behaviour: insights from crystal structures and computational surface analysis

Seven venetoclax solvates were structurally characterized and studied for their desolvation behaviour, leading to the identification of two solvent-free polymorphs. Advanced crystallographic and computational analyses, including Solvate Analyser, CSD-Particle, FTIR and solid-state NMR, revealed key factors governing solvate stability and transformation. Notably, the acetone solvate exhibited exceptional stability and the desolvated forms retained the molecular arrangement of their parent solvates.

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