Is artificial intelligence magic dust for big-science facilities?

AI is no magic dust: for it to become a true discovery accelerator, much work is needed to make it transparent and robust.

Mirolysin structures open a window on gum disease

Guevara, Rodriguez-Banqueri et al. [(2020), IUCrJ, 7, 18–29] determine crystal structures of mirolysin, a metalloprotease that helps oral pathogen Tannerella forsythia evade the human immune response. The structures provide insight into the regulation and specificity of mirolysin, and hint at how it might be inhibited for therapeutic effect.

Polymorph evolution during crystal growth studied by 3D electron diffraction

3D electron diffraction has been used to follow polymorph evolution during the crystallization of glycine from pure water. All three known polymorphs formed sequentially in samples taken from the same solution and allowed to crystallize in situ at times between 3 and 60 min. Crystal structures were obtained for all three phases.

Refinement for single-nanoparticle structure determination from low-quality single-shot coherent diffraction data

A refinement method of the structure from a low-intensity diffraction pattern is proposed and applied to a diffraction pattern from a sub-micrometre cluster. It is shown that the method could retrieve a 2D projection of the electron density that is physically meaningful.

Structure-based mechanism of cysteine-switch latency and of catalysis by pappalysin-family metallopeptidases

The members of the unicellular pappalysin family of metallopeptidases are secreted as zymogens with a short N-terminal pro-segment, which blocks the catalytic zinc cation by a cysteine-switch mechanism, as shown structurally for bacterial mirolysin. This is a mechanism to prevent activity in the absence of the adequate temporal and spatial requisites. In addition, the complex of mirolysin with a large peptide reveals the structural basis of its catalytic mechanism.

A fixed-target platform for serial femtosecond crystallography in a hydrated environment

This work demonstrates the use of polymer thin films and graphene to support and maintain the hydration of protein microcrystals on fixed targets for serial femtosecond crystallography at X-ray free-electron lasers. Rapid encystment protein (REP24) provides a benchmark for this encapsulation approach.

Distinguishing contributions of ceramic matrix and binder metal to the plasticity of nanocrystalline cermets

Contributions to plasticity from hard matrix and binder metal in nanocrystalline cermets were studied by molecular dynamics simulations.

Investigation of growth characteristics and semimetal–semiconductor transition of polycrystalline bis­muth thin films

The effect of substrate temperature, growth rate and film thickness on the crystallographic characteristics of polycrystalline Bi thin films by molecular beam epitaxy and semimetal–semiconductor transition are discussed. Meanwhile, a structure-zone model and a two-transport-channels model are introduced to explain the crystal growth characteristics and the semimetal–semiconductor transition.

High-pressure polymorphism in pyridine

Pyridine phase III, which forms at 1.69 GPa, is tetragonal and related to the previously characterized orthorhombic form II by a displacive phase transition. Phase III is similar to a high-pressure form of benzene. The soft mode governing the III→II transition has been identified using a combination of symmetry mode analysis and periodic density functional theory. A combination of single-crystal X-ray diffraction and Raman spectroscopy is used to resolve ambiguities in previous work on pyridine.

Charge density view on bicalutamide molecular interactions in the monoclinic polymorph and androgen receptor binding pocket

Experimental and theoretical electron density distributions and the nature of intermolecular interactions of bicalutamide in its monoclinic polymorph and in androgen receptor complexes are reported.

Extraordinary anisotropic thermal expansion in photosalient crystals

Single crystals of three isotypical Cu(II) coordination complexes with paddlewheel structures exhibit mechanical motion while undergoing [2+2] cyclo­addition under UV light (photosalient effect), and also exhibit large positive thermal expansion on heating.

Structural and kinetic insights into flavin-containing monooxygenase and calponin-homology domains in human MICAL3

The structure of human MICAL3 provides information about its mechanism.

Operando X-ray scattering study of thermoelectric β-Zn₄Sb₃

A thermoelectric operando setup for synchrotron X-ray scattering has been developed in order to study the operational stability of thermoelectric materials in real-world conditions.

Crystal engineering of exemestane to obtain a co-crystal with enhanced urease inhibition activity

Co-crystals of the commercially available anticancer aromatase inhibitor exemestane (Ex) and guest co-former thio­urea were synthesized and the difference in the biological properties of the co-crystal compared with Ex was investigated. To study the various intermolecular interactions and their contribution to the structure stability, Hirshfeld surface analysis was successfully employed, and thermal stability was evaluated by DSC and TGA.

Synthesis, structure, magnetic and half-metallic properties of Co_2−xRu_xMnSi (x = 0, 0.25, 0.5, 0.75, 1) compounds

The structural, electronic, magnetic and transport properties of half metallic Co_2−xRu_xMnSi (x = 0–1) Heusler compounds are studied both theoretically and experimentally. Our computations and experiments soundly agree with each other.

Extraordinary structural complexity of ilmajokite: a multilevel hierarchical framework structure of natural origin

Ilmajokite, a natural titanosilicate found in the Russian Arctic, has an extraordinary complex microporous framework structure consisting of several levels of hierarchical organization.

Measuring energy-dependent photoelectron escape in microcrystals

An increase in crystal lifetime resulting from photoelectron escape was measured on the microfocus beamline I24 at Diamond Light Source for hen-egg white lysozyme microcrystals mounted on cryo-TEM grids at 13.5 and 20.1 keV using a PILATUS CdTe detector.

Magnetic Guinier law

The Guinier law for magnetic SANS on bulk ferromagnets is introduced and applied to the analysis of nanocrystalline cobalt. The magnetic-field-dependent Guinier radius reflects the characteristic microstructural size and depends on the magnetic interactions.