Operando structural science of functional materials

This editorial gives a brief overview of operando structural science of functional materials with emphasis on catalytic science.

John C. H. Spence (1946–2021)

Obituary for John C. H. Spence.

Prism-based scanning X-ray microscopy

A commentary is provided on a new type of prism deflection scanning X-ray microscope, providing context and some future potential applications of this new type of microscope.

Lipid transport across the mycobacterial cell envelope

The mammalian-cell-entry (Mce) proteins of Mycobacterium tuberculosis enable the bacterium to acquire lipids from the host cells. Asthana et al. [IUCrJ (2021). 8, 757–774] present the first structural insights into the potential assembly of Mce1 and Mce4, advancing our understanding of lipid transport by the human pathogen that causes tuberculosis.

Hard X-ray nanoprobe scanner

A scheme for high-resolution X-ray microscopy by scanning the nanoprobe, rather than the sample, has been demonstrated. A combination of X-ray prisms and advanced reflective mirror optics offer a simple and precise nanoprobe scan that will open new opportunities for microscopic X-ray analyses.

Deep learning for improving non-destructive grain mapping in 3D

A deep learning neural network has been developed to efficiently and accurately clean the background noise in experimental lab-based X-ray diffraction images. A better spot segmentation is obtained and thus grain mapping in 3D is improved compared with the conventional method.

Conformational flexibility of EptA driven by an interdomain helix provides insights for enzyme–substrate recognition

Small-angle X-ray scattering and tryptophan fluorescence studies of phospho­ethano­lamine transferase (EptA) suggest conformational flexibility linked to enzyme activity.

Orientational mapping of minerals in Pierre shale using X-ray diffraction tensor tomography

X-ray diffraction tensor tomography is used to map clay mineral orientation and high-density inclusions in a sample of Pierre shale.

Structural insights into the substrate-binding proteins Mce1A and Mce4A from Mycobacterium tuberculosis

The mammalian cell entry genes (mceA–mceF) encode the substrate-binding proteins of the lipid-transporting Mce complexes in mycobacteria. The MCE domain of Mce4A has been crystallized as a domain-swapped dimer with the signature β-barrel fold. Solution studies show that the domains of Mce1A and Mce4A are predominantly monomeric and suggest that the helical domain is involved in lipid interactions.

Microsecond hydrodynamic interactions in dense colloidal dispersions probed at the European XFEL

The dynamics of small nanoparticles dispersed in water are probed with multi-speckle XPCS taking advantage of the pulse structure of the European XFEL. The time resolution is sufficient to correctly probe the many-body hydrodynamic interactions in samples both at equilibrium and driven by the XFEL pulses. Practical examples demonstrate how X-ray pulse-induced dynamics can be controlled.

Millisecond mix-and-quench crystallography (MMQX) enables time-resolved studies of PEPCK with remote data collection

Improvements in cryo-trapping technology enable single-crystal time-resolved crystallography of an enzyme with 40 ms time resolution.

Geometrical prediction of cleavage planes in crystal structures

A new geometrical approach is proposed for finding the most prominent planar gaps/cleavage planes in crystal structures. The approach is realized by using the GALOCS program package and is demonstrated on several inorganic structures.

UnitCell Tools, a package to determine unit-cell parameters from a single electron diffraction pattern

The UnitCell Tools package was developed to determine unit-cell parameters of a crystal from a single electron diffraction pattern with high-order Laue zone reflections acquired in the conventional transmission electron microscope.

Template design based on molecular and crystal structure similarity to regulate conformational polymorphism nucleation: the case of α,ω-alkanedi­carb­oxy­lic acids

A method of regulating the crystallization of conformational polymorphs based on the crystal structure similarity of templates and the target crystal form has been developed.

Chasing the structural diversity of the transcription regulator Mycobacterium tuberculosis HigA2

Three crystal structures of the transcription regulator HigA2 from Mycobacterium tuberculosis reveal a flexible dimerization mode, which affects its interaction with DNA.

Qu­antifying magnetic anisotropy using X-ray and neutron diffraction

A combination of powder and single-crystal polarized neutron diffraction, very low temperature synchrotron X-ray diffraction and ab initio calculations can be used to quantify and explain the magnetic anisotropy in Co(II) single-molecule magnets.

Crystal structure of a MarR family protein from the psychrophilic bacterium Paenisporosarcina sp. TG-14 in complex with a lipid-like molecule

The crystal structure of the MarR protein from Paenisporosarcina sp. TG-14 is reported at 1.6 Å resolution.