Findable Accessible Interoperable Re-usable (FAIR) diffraction data are coming to protein crystallography

The policy of IUCr Journals on diffraction data is defined.

Shedding light on decahedral nanoparticle catalysts

Control over the chemical composition and atomic ordering in bimetallic nanoparticles has driven the recent rapid progress in electrocatalysis. Liang & Yu [IUCrJ (2019), 6, 447–453] elucidate the structural differences between single metal and intermetallic multiply twinned decahedral nanoparticles on the example of AuCu particles and correlate the catalytic properties with their structure at the atomic level.

Ice formation and solvent nanoconfinement in protein crystals

Nanoconfinement dramatically modifies the behaviour of solvent within protein crystals, allowing biophysical measurements in the presence of liquid solvent at temperatures down to ∼200 K. When internal ice forms it is stacking-disordered, consistent with nucleation within deeply supercooled solvent, and ice does not form in solvent within ∼5 Å of the protein surface.

Experimental 3D coherent diffractive imaging from photon-sparse random projections

The application of X-ray coherent diffractive imaging to structure determination of single biomolecules at free electron lasers yields signal levels down to a few hundred scattered photons per frame or less. Here we demonstrate in an analog experiment at a synchrotron source that even at a sparsity level of order 1.3 × 10⁻³ photons per pixel per frame the 3D structure of a nano-fabricated sample can be obtained, even if the orientation of the particle for a given individual frame is not explicitly known.

Stress-induced detwinning and martensite transformation in an austenite Ni–Mn–Ga alloy with martensite cluster under uniaxial loading

A dual-phase Ni–Mn–Ga alloy, composed of an austenite matrix with stably existing martensite embryos, was designed for the experimental and theoretical investigation of the evolution of the crystallographic structure during step-wise stress-induced martensite detwinning and martensite transformation. This research provides an insight into the detwinning mechanisms of a hierarchical twinning structure and crystallographic characterization of a three-stage austenite–martensite transformation.

Long-wavelength native-SAD phasing: opportunities and challenges

Advantages of using a wavelength of 2.7 Å over a wavelength of 1.9 Å for native single-wavelength anomalous dispersion phasing are presented, and potentials of using a wavelength of 3.3 Å are discussed.

Subatomic resolution X-ray structures of green fluorescent protein

Subatomic resolution X-ray structures of green fluorescent protein are reported.

Determination of the molecular basis for coprogen import by Gram-negative bacteria

This work presents the crystal structure and functional characterization of FhuE, the bacterial outer membrane transporter responsible for the import of coprogen. Coprogen is an iron-scavenging compound produced by fungi, and FhuE allows bacteria to engage in iron piracy from fungal competitors.

High-viscosity injector-based pink-beam serial crystallography of microcrystals at a synchrotron radiation source

This article presents the first injector-based serial crystallography experiments carried out at a pink X-ray beam source, the BioCARS beamline at the Advanced Photon Source. Microcrystals of human A_2A adenosine receptor and proteinase K were screened and the structures determined to resolutions of 4.2 and 1.8 Å, respectively.

Cryo-EM reveals the asymmetric assembly of squid hemocyanin

The cryo-EM structure of squid hemocyanin, obtained using a multi-symmetry refinement protocol in SPHIRE, reveals an unexpected breaking of fivefold symmetry in the central ring and a striking arrangement of the subunits.

Unexpected phase transition sequence in the ferroelectric Bi₄Ti₃O₁₂

A detailed powder neutron diffraction study reveals that the layered perovskite ferroelectric Bi₄Ti₃O₁₂ undergoes an unusual phase transition sequence, exhibiting an unexpected and unique octahedral-tilted phase above T_C.

Understanding the formation of multiply twinned structure in decahedral intermetallic nanoparticles

The formation of multiply twinned structures in decahedral intermetallic nanoparticles has been explored and a general framework proposed to understand it.

A simple and versatile microfluidic device for efficient biomacromolecule crystallization and structural analysis by serial crystallography

An innovative microfluidic design (ChipX3) is described for simple biomacromolecule crystallization by counter-diffusion, allowing semi-automated structural analysis by serial crystallography at room temperature. The functionalities of ChipX3 are demonstrated using case studies leading to high-resolution structures of four proteins and an RNA.

Competition between cubic and tetragonal phases in all-d-metal Heusler alloys, X_2−xMn_1+xV (X = Pd, Ni, Pt, Ag, Au, Ir, Co; x = 1, 0): a new potential direction of the Heusler family

Changes in the c/a ratio and the effect of uniform strain for the tetragonal transformation of X_2 − xMn_1 + xV (X = Pd, Ni, Pt, Ag, Au, Ir, Co; x = 1, 0) were studied. Surprisingly, all the Mn-poor alloys undergo possible tetragonal distortion and attain a stable tetragonal phase, whereas Mn-rich alloys do not have, or have only to a small extent, tetragonal distortion.

Qu­antitative disentanglement of nanocrystalline phases in cement pastes by synchrotron ptychographic X-ray tomography

The density and content of an amorphous component in cement pastes has been quantified by ptychography in the presence of a large amount of another different amorphous component.

Structure and magnetic properties of W-type hexaferrites

W-type hexaferrites were investigated by both X-ray and neutron powder diffraction along with macroscopic measurements. The refined nuclear structure and magnetic ordering are in good agreement with the measured magnetic properties, solidifying the robustness of using X-rays and neutrons in conjunction.

Experimental strategies for imaging bioparticles with femtosecond hard X-ray pulses. Corrigendum

Corrigendum to the article by Daurer et al. [IUCrJ (2017). 4, 251–262.].