Recent trends in crystallography – a current IUCr journals perspective

This Editorial considers the impact of recent work published in IUCrJ and other IUCr journals, as well as the relationship between IUCrJ and the other journals, in terms of where the most cited recent papers are used.

A potential difference for single-particle cryo-EM

Nydenova et al. [(2019), IUCrJ, 6, 1086–1098] determine structures of frozen-hydrated protein and nucleic acid assemblies using 100 keV electrons, and describe characteristics of electron microscopes designed to exploit advantages of a lower operating voltage for single-particle cryo-EM.

R3c-type LnNiO₃ (Ln = La, Ce, Nd, Pm, Gd, Tb, Dy, Ho, Er, Lu) half-metals with multiple Dirac cones: a potential class of advanced spintronic materials

In this study, an experimentally synthesized DHM LaNiO₃ is discovered with many Dirac cones and complete spin polarization near the Fermi level via first principles; it is also shown that the crystal structures of these materials are strongly correlated with their physical properties.

Mutagenesis facilitated crystallization of GLP-1R

The ∼100 mutations used during the structural determination of GLP-1R suggest multiple mutagenesis strategies, which may find applications in the crystallization of G-protein-coupled receptors and other membrane proteins, and potentially in functional and pharmacological studies by locking proteins into specific conformations.

Throughput and resolution with a next-generation direct electron detector

The superior image quality given by the DE64 direct electron detector in counting mode is more important for high-resolution cryo-EM reconstructions than its superior throughput in integrating mode.

Engineering a surrogate human heteromeric α/β glycine receptor orthosteric site exploiting the structural homology and stability of acetylcholine-binding protein

The development and characterization of a surrogate system to support drug discovery targeting a complex heteromeric human glycine receptor is described.

A cryo-EM grid preparation device for time-resolved structural studies

Time-resolved structural studies are becoming an important tool in understanding biological function. Here we describe a cryo-EM grid freezing device capable of rapidly mixing and plunge freezing grids within 10 ms.

Diversifying molecular and topological space via a supramolecular solid-state synthesis: a purely organic mok net sustained by hydrogen bonds

A hydrogen-bond-directed [2+2] photodimerization performed in the solid state is used to generate a head-to-head (HH) cyclo­butane photoproduct functionalized with cis-phenolic and cis-pyridyl groups. The photoproduct self-assembles as a pure form in the solid state to form a rare three-dimensional hydrogen-bonded network with a topology that conforms to a mok net. The construction of the HH cyclo­butane is achieved using a newly introduced supramolecular protecting-group strategy.

Resolution and dose dependence of radiation damage in biomolecular systems

Data from several radiation-damage studies using protein crystals are reanalyzed to determine the local dose- and resolution-dependent decay of diffracted intensity at T = 100 K. The results are inconsistent with long-accepted models and with a proposed linear scaling between maximum tolerable dose and resolution, but are reproduced by a simple, physics-based model.

DeepRes: a new deep-learning- and aspect-based local resolution method for electron-microscopy maps

A method (DeepRes) is presented to estimate a new local quality measure for 3D cryoEM maps that adopts the form of a `local resolution' type of information. DeepRes is fully automatic and parameter-free and avoids the issues of most current methods, such as their insensitivity to enhancements owing to B-factor sharpening, among others.

Consistency and variability of cocrystals containing positional isomers: the self-assembly evolution mechanism of supramolecular synthons of cresol–piperazine

The consistency and variability as well as self-assembly evolution mechanism of cresol–piperazine cocrystals are investigated by experiments and molecular simulation.

High-throughput structures of protein–ligand complexes at room temperature using serial femtosecond crystallography

The ability to rapidly obtain structures of protein–ligand complexes using X-ray crystallography is central to drug discovery, but the typical cryocooling of samples and the effects of the X-ray beam may distort the observed ligand binding. X-ray free-electron lasers (XFELs) have the promise to solve these issues, but methods to rapidly produce structures of protein–ligand complexes at XFELs have not yet been realized. Here, an efficient solution using high-throughput, fixed-target serial femtosecond crystallography at an XFEL is demonstrated.

CryoEM at 100 keV: a demonstration and prospects

Several structures were determined by single-particle cryoEM at 100 keV and the implications for future electron cryomicroscopes are considered.

A comparative study of single-particle cryo-EM with liquid-nitrogen and liquid-helium cooling

Radiation damage is the most fundamental limitation for achieving high resolution in cryo-EM, and is expected to be reduced at liquid-helium temperature. Surprisingly, cryo-EM reconstructions of apoferritin samples cooled with liquid helium showed no improvement in resolution over liquid-nitro­gen-cooled samples, but showed substantially more beam-induced particle motion.

Toward G protein-coupled receptor structure-based drug design using X-ray lasers

A method is presented for efficient co-crystal structure determination for G protein-coupled receptors taking advantage of serial femtosecond crystallography.

Crystal structure of the putative cyclase IdmH from the indanomycin nonribosomal peptide synthase/polyketide synthase

The crystal structure of IdmH from the biosynthetic gene cluster for indanomycin is presented. NMR data show that this enzyme binds its postulated product, indanomycin, and QM/MM modelling of the reaction strongly supports the view that IdmH catalyses indane-ring formation in indanomycin biosynthesis via a Diels–Alder reaction.