d

Preparing research samples for safe arrival at centers and facilities: recipes for successful experiments

Preparation of biomacromolecules for structural biology studies is a complex and time-consuming process. The goal is to produce a highly concentrated, highly pure product that is often shipped to large facilities with tools to prepare the samples for crystallization trials or for measurements at synchrotrons and cryoEM centers. The aim of this article is to provide guidance and to discuss general considerations for shipping biomacromolecular samples. Details are also provided about shipping samples for specific experiment types, including solution- and cryogenic-based techniques. These guidelines are provided with the hope that the time and energy invested in sample preparation is not lost due to shipping logistics.




d

Structures of Brucella ovis leucine-, isoleucine-, valine-, threonine- and alanine-binding protein reveal a conformationally flexible peptide-binding cavity

Brucella ovis is an etiologic agent of ovine epididymitis and brucellosis that causes global devastation in sheep, rams, goats, small ruminants and deer. There are no cost-effective methods for the worldwide eradication of ovine brucellosis. B. ovis and other protein targets from various Brucella species are currently in the pipeline for high-throughput structural analysis at the Seattle Structural Genomics Center for Infectious Disease (SSGCID), with the aim of identifying new therapeutic targets. Furthermore, the wealth of structures generated are effective tools for teaching scientific communication, structural science and biochemistry. One of these structures, B. ovis leucine-, isoleucine-, valine-, threonine- and alanine-binding protein (BoLBP), is a putative periplasmic amino acid-binding protein. BoLBP shares less than 29% sequence identity with any other structure in the Protein Data Bank. The production, crystallization and high-resolution structures of BoLBP are reported. BoLBP is a prototypical bacterial periplasmic amino acid-binding protein with the characteristic Venus flytrap topology of two globular domains encapsulating a large central cavity containing the peptide-binding region. The central cavity contains small molecules usurped from the crystallization milieu. The reported structures reveal the conformational flexibility of the central cavity in the absence of bound peptides. The structural similarity to other LBPs can be exploited to accelerate drug repurposing.




d

Crystallographic fragment screen of the c-di-AMP-synthesizing enzyme CdaA from Bacillus subtilis

Crystallographic fragment screening has become a pivotal technique in structure-based drug design, particularly for bacterial targets with a crucial role in infectious disease mechanisms. The enzyme CdaA, which synthesizes an essential second messenger cyclic di-AMP (c-di-AMP) in many pathogenic bacteria, has emerged as a promising candidate for the development of novel antibiotics. To identify crystals suitable for fragment screening, CdaA enzymes from Streptococcus pneumoniae, Bacillus subtilis and Enterococcus faecium were purified and crystallized. Crystals of B. subtilis CdaA, which diffracted to the highest resolution of 1.1 Å, were used to perform the screening of 96 fragments, yielding data sets with resolutions spanning from 1.08 to 1.87 Å. A total of 24 structural hits across eight different sites were identified. Four fragments bind to regions that are highly conserved among pathogenic bacteria, specifically the active site (three fragments) and the dimerization interface (one fragment). The coordinates of the three active-site fragments were used to perform an in silico drug-repurposing screen using the OpenEye suite and the DrugBank database. This screen identified tenofovir, an approved drug, that is predicted to interact with the ATP-binding region of CdaA. Its inhibitory potential against pathogenic E. faecium CdaA has been confirmed by ITC measurements. These findings not only demonstrate the feasibility of this approach for identifying lead compounds for the design of novel antibacterial agents, but also pave the way for further fragment-based lead-optimization efforts targeting CdaA.




d

Glucose-6-phosphate dehydrogenase and its 3D structures from crystallography and electron cryo-microscopy

Glucose-6-phosphate dehydrogenase (G6PD) is the first enzyme in the pentose phosphate pathway. It has been extensively studied by biochemical and structural techniques. 13 X-ray crystal structures and five electron cryo-microscopy structures in the PDB are focused on in this topical review. Two F420-dependent glucose-6-phosphate dehydrogenase (FGD) structures are also reported. The significant differences between human and parasite G6PDs can be exploited to find selective drugs against infections such as malaria and leishmaniasis. Furthermore, G6PD is a prognostic marker in several cancer types and is also considered to be a tumour target. On the other hand, FGD is considered to be a target against Mycobacterium tuberculosis and possesses a high biotechnological potential in biocatalysis and bioremediation.




d

First crystal structure of the DUF2436 domain of virulence proteins from Porphyromonas gingivalis

Porphyromonas gingivalis is a major pathogenic oral bacterium that is responsible for periodontal disease. It is linked to chronic periodontitis, gingivitis and aggressive periodontitis. P. gingivalis exerts its pathogenic effects through mechanisms such as immune evasion and tissue destruction, primarily by secreting various factors, including cysteine proteases such as gingipain K (Kgp), gingipain R (RgpA and RgpB) and PrtH (UniProtKB ID P46071). Virulence proteins comprise multiple domains, including the pro-peptide region, catalytic domain, K domain, R domain and DUF2436 domain. While there is a growing database of knowledge on virulence proteins and domains, there was no prior evidence or information regarding the structure and biological function of the well conserved DUF2436 domain. In this study, the DUF2436 domain of PrtH from P. gingivalis (PgDUF2436) was determined at 2.21 Å resolution, revealing a noncanonical β-jelly-roll sandwich topology with two antiparallel β-sheets and one short α-helix. Although the structure of PgDUF2436 was determined by the molecular-replacement method using an AlphaFold model structure as a template, there were significant differences in the positions of β1 between the AlphaFold model and the experimentally determined PgDUF2436 structure. The Basic Local Alignment Search Tool sequence-similarity search program showed no sequentially similar proteins in the Protein Data Bank. However, DaliLite search results using structure-based alignment revealed that the PgDUF2436 structure has structural similarity Z-scores of 5.9–5.4 with the C-terminal domain of AlgF, the D4 domain of cytolysin, IglE and the extracellular domain structure of PepT2. This study has elucidated the structure of the DUF2436 domain for the first time and a comparative analysis with similar structures has been performed.




d

Ternary structure of Plasmodium vivax N-myristoyltransferase with myristoyl-CoA and inhibitor IMP-0001173

Plasmodium vivax is a major cause of malaria, which poses an increased health burden on approximately one third of the world's population due to climate change. Primaquine, the preferred treatment for P. vivax malaria, is contraindicated in individuals with glucose-6-phosphate dehydrogenase (G6PD) deficiency, a common genetic cause of hemolytic anemia, that affects ∼2.5% of the world's population and ∼8% of the population in areas of the world where P. vivax malaria is endemic. The Seattle Structural Genomics Center for Infectious Disease (SSGCID) conducted a structure–function analysis of P. vivax N-myristoyltransferase (PvNMT) as part of efforts to develop alternative malaria drugs. PvNMT catalyzes the attachment of myristate to the N-terminal glycine of many proteins, and this critical post-translational modification is required for the survival of P. vivax. The first step is the formation of a PvNMT–myristoyl–CoA binary complex that can bind to peptides. Understanding how inhibitors prevent protein binding will facilitate the development of PvNMT as a viable drug target. NMTs are secreted in all life stages of malarial parasites, making them attractive targets, unlike current antimalarials that are only effective during the plasmodial erythrocytic stages. The 2.3 Å resolution crystal structure of the ternary complex of PvNMT with myristoyl-CoA and a novel inhibitor is reported. One asymmetric unit contains two monomers. The structure reveals notable differences between the PvNMT and human enzymes and similarities to other plasmodial NMTs that can be exploited to develop new antimalarials.




d

Multi-species cryoEM calibration and workflow verification standard

Cryogenic electron microscopy (cryoEM) is a rapidly growing structural biology modality that has been successful in revealing molecular details of biological systems. However, unlike established biophysical and analytical techniques with calibration standards, cryoEM has lacked comprehensive biological test samples. Here, a cryoEM calibration sample consisting of a mixture of compatible macromolecules is introduced that can not only be used for resolution optimization, but also provides multiple reference points for evaluating instrument performance, data quality and image-processing workflows in a single experiment. This combined test specimen provides researchers with a reference point for validating their cryoEM pipeline, benchmarking their methodologies and testing new algorithms.




d

Duality of spaces and the origin of integral reflection conditions

The reciprocal of a non-primitive unit cell is not a unit cell and the basis vectors do not correspond to cell lengths.




d

Animations, videos and 3D models for teaching space-group symmetry

Animations, videos and 3D models have been designed to visualize the effects of symmetry operators on selected cases of crystal structures, pointing out the relationship with the diagrams published in International Tables for Crystallography, Vol. A.




d

Sheet-on-sheet fixed target data collection devices for serial crystallography at synchrotron and XFEL sources

Fixed targets (`chips') offer efficient, high-throughput microcrystal delivery for serial crystallography at synchrotrons and X-ray free-electron lasers (XFELs). Within this family, sheet-on-sheet (SOS) chips offer noteworthy advantages in cost, adaptability, universality and ease of crystal loading. We describe our latest generation of SOS devices, which are now in active use at both synchrotrons and XFELs.




d

Laboratory X-ray powder micro-diffraction in the research of painted artworks

This review summarizes the methodological aspects of laboratory X-ray powder micro-diffraction and demonstrates the assets of the method in the research of painted artworks for evaluation of their provenance or diagnosing their degradation.




d

Mapping domain structures near a grain boundary in a lead zirconate titanate ferroelectric film using X-ray nanodiffraction

Direct measurements have been taken of nanoscale domain structure in ferroelectric lead zirconate titanate around a grain boundary. Characterizing the evolution of this structure under an electric field is critical for predicting dielectric and piezoelectric response.




d

Optimizing crucible geometry to improve the quality of AlN crystals by the physical vapor transport method

The growth quality of AlN single crystals was improved by optimizing the crucible structure for Al vapor transport with the help of finite element simulation.




d

Grazing-incidence small-angle neutron scattering at high pressure (HP-GISANS): a soft matter feasibility study on grafted brush films

We present a demonstration of high-pressure grazing-incidence small-angle neutron scattering for soft matter thin films. The results suggest changes in water reorganization at different pressures.




d

A micro-beamstop with transmission detection by fluorescence for scanning-beam synchrotron scattering beamlines

The correct determination of X-ray transmission at X-ray nanoprobes equipped with small beamstops for small- and wide-angle X-ray scattering collection is an unsolved problem with huge implications for data correction pipelines. We present a cost-effective solution to detect the transmission via the X-ray fluorescence of the beamstop with an avalanche photodiode.




d

Integrating machine learning interatomic potentials with hybrid reverse Monte Carlo structure refinements in RMCProfile

New software capabilities in RMCProfile allow researchers to study the structure of materials by combining machine learning interatomic potentials and reverse Monte Carlo.




d

Improving the reliability of small- and wide-angle X-ray scattering measurements of anisotropic precipitates in metallic alloys using sample rotation

Rotations of small- and wide-angle X-ray scattering samples during acquisition are shown to give a drastic improvement in the reliability of the characterization of anisotropic precipitates in metallic alloys.




d

Understanding secondary order parameters in perovskites with tilted octahedra

A symmetry guide for the secondary structural degrees of freedom and related physical properties generated by tilts of BX6 octahedra in perovskites is proposed.




d

Multi-scale and time-resolved structure analysis of relaxor ferroelectric crystals under an electric field

The electric field responses of the average and local lattice strains and polar nanoregions of relaxor ferroelectric PMN-30PT single crystals were revealed by multi-scale and time-resolved X-ray diffraction under DC and AC electric fields.




d

AnACor2.0: a GPU-accelerated open-source software package for analytical absorption corrections in X-ray crystallography

AnACor2.0 significantly accelerates the calculation of analytical absorption corrections in long-wavelength crystallography, achieving up to 175× speed improvements. This enhancement is achieved through innovative sampling techniques, bisection and gridding methods, and optimized CUDA implementations, ensuring efficient and accurate results.




d

The effects of low boron incorporation on the structural and optical properties of BxGa1−xN/SiC epitaxial layers

The effect of boron in BxGa1−xN/SiC heteroepitaxy was established by X-ray diffraction reciprocal-space maps on symmetric 0002 and asymmetric 11 {overline 2} 4 reflections. The density of screw and edge threading dislocations was quantified in the framework of the mosaic model.




d

Exploiting Friedel pairs to interpret scanning 3DXRD data from complex geological materials

A new processing technique for synchrotron scanning 3D X-ray diffraction data is introduced, utilizing symmetric Bragg reflections hkl and hkl, known as Friedel pairs. This technique is designed to tackle the difficulties associated with large, highly deformed, polyphase materials, especially geological samples.




d

Towards expansion of the MATTS data bank with heavier elements: the influence of the wavefunction basis set on the multipole model derived from the wavefunction

This study examines the quality of charge density obtained by fitting the multipole model to wavefunctions in different basis sets. The complex analysis reveals that changing the basis set quality from double- to triple-zeta can notably improve the charge density related properties of a multipole model.




d

Real-time analysis of liquid-jet sample-delivery stability for an X-ray free-electron laser using machine vision

This paper describes real-time statistical analysis of liquid jet images for SFX experiments at the European XFEL. This analysis forms one part of the automated jet re-alignment system for SFX experiments at the SPB/SFX instrument of European XFEL.




d

Small-angle scattering and dark-field imaging for validation of a new neutron far-field interferometer

A neutron far-field interferometer is under development at NIST with the aim of enabling a multi-scale measurement combining the best of small-angle neutron scattering (SANS) and neutron imaging and tomography. We use the close relationship between SANS, ultra-SANS, spin-echo SANS and dark-field imaging and measurements of monodisperse spheres as a validation metric, highlighting the strengths and weaknesses of each of these neutron techniques.




d

Characterization and calibration of DECTRIS PILATUS3 X CdTe 2M high-Z hybrid pixel detector for high-precision powder diffraction measurements

The performance of a high-Z photon-counting detector for powder diffraction measurements at high (>50 keV) energies is characterized, and the appropriate corrections are described in order to obtain data of higher quality than have previously been obtained from 2D detectors in these energy ranges.




d

Modulating phase segregation during spin-casting of fullerene-based polymer solar-cell thin films upon minor addition of a high-boiling co-solvent

Combined 100 ms resolved grazing-incidence small/wide-angle X-ray scattering and optical interferometry reveal that the additive diiodooctane can significantly double the solvent evaporation rate, thereby effectively suppressing the rapid spinodal decomposition process in the early stage of spin-coasting, favouring slow phase segregation kinetics with nucleation and growth.




d

Position-independent product increase rate in a shaker mill revealed by position-resolved in situ synchrotron powder X-ray diffraction

The position- and time-resolved monitoring of a mechanochemical reaction using synchrotron powder X-ray diffraction revealed a position-independent increase rate of product in the jar of a shaker mill.




d

Non-invasive nanoscale imaging of protein micro- and nanocrystals for screening crystallization conditions

The article presents a non-invasive nanoscale imaging technique that can be used in screening crystallization conditions for protein micro- and nanocrystals.




d

RAPID, an ImageJ macro for indexing electron diffraction zone axis spot patterns of cubic materials

RAPID (RAtio method Pattern InDexing) is an ImageJ macro script developed for the quick determination of sample orientation and indexing of calibrated and uncalibrated zone axis aligned electron diffraction patterns from materials with a cubic crystal structure. In addition to SAED and NBED patterns, the program is also capable of handling zone axis TEM Kikuchi patterns and FFTs derived from HR(S)TEM images. The software enables users to rapidly determine whether materials are cubic, pseudo-cubic, or non-cubic, and to distinguish between P, I, and F Bravais lattices. It can also provide lattice parameters for material verification and aid in determining the camera constant of the instrument, thus making the program a convenient tool for on-site crystallographic analysis in the TEM laboratory.




d

Optimal operation guidelines for direct recovery of high-purity precursor from spent lithium-ion batteries: hybrid operation model of population balance equation and data-driven classifier

This study proposes an operation optimization framework for impurity-free recycling of spent lithium-ion batteries. Using a hybrid population balance equation integrated with a data-driven condition classifier, the study firstly identifies the optimal batch and semi-batch operation conditions that significantly reduce the operation time with 100% purity of product; detailed guidelines are given for industrial applications.




d

Advanced EXAFS analysis techniques applied to the L-edges of the lanthanide oxides

The L-edge EXAFS of the entire set of lanthanide oxides were collected and modeled, taking into consideration the aggregation of inequivalent absorbing sites, geometric parameterization of the crystal lattice and multielectron excitation removal.




d

TOMOMAN: a software package for large-scale cryo-electron tomography data preprocessing, community data sharing and collaborative computing

Here we describe TOMOMAN (TOMOgram MANager), an extensible open-sourced software package for handling cryo-electron tomography data preprocessing. TOMOMAN streamlines interoperability between a wide range of external packages and provides tools for project sharing and archival.




d

Multimodal reconstruction of TbCo thin-film structure with Bayesian analysis of polarized neutron reflectivity

For the first time, a multimodal reconstruction of a magnetic thin-film structure has been found using polarised neutron reflectivity. This has been achieved by implementing the Bayesian approach in combination with error correction based on the maximum likelihood method and instrument function optimization.




d

GRASP Integrated 3D Plotter: GRIP

This article describes the implementation of GRIP as a module of GRASP, enabling the fully three-dimensional visualization and analysis of data collected on small-angle neutron scattering instruments.




d

Specific radiation damage to halogenated inhibitors and ligands in protein–ligand crystal structures

This article reports an investigation into the effects of specific radiation damage to halogenated ligands in crystal structures of protein-inhibitor complexes.




d

High accuracy, high resolution measurements of fluorescence in manganese using extended-range high-energy-resolution fluorescence detection

We explain analysis of RIXS, HERFD and XR-HERFD data to discover new physical processes in manganese and manganese-containing materials, by applying our new technique XR-HERFD, developed from high resolution RIXS and HERFD.




d

Effect of thickness and noise on angular correlation analysis from scanning electron nanobeam diffraction of disordered carbon

The impact of sample thickness and experimental noise on angular correlation analysis from scanning electron nanobeam diffraction patterns of disordered carbon are investigated and analyzed regarding the interpretability of the analysis results.




d

Variable temperature studies of tetra­pyridine­silver(I) hexa­fluoro­phosphate and tetra­pyridine­silver(I) hexa­fluoro­anti­monate

Structures of tetra­pyridine­silver(I) hexa­fluoro­phosphate and tetra­pyridine silver(I) hexa­fluoro­anti­monate are reported from data collected at 300 K and 100 K.




d

The cadmium oxidotellurates(IV) Cd5(TeO3)4(NO3)2 and Cd4Te5O14

The crystal structure of Cd5(TeO3)4(NO3)2 exhibits a distinct layered arrangement, whereas Cd4Te5O14 crystallizes with a framework structure.




d

Crystal structure and Hirshfeld surface analysis of bis­(benzoyl­acetonato)(ethanol)dioxidouranium(VI)

In the complex, the ligand binds to the metal through an oxygen atom. The geometry of the seven-coordinate U atom is penta­gonal bipyramidal, with the uranyl O atoms in apical positions.




d

Synthesis and structure of penta­kis­(2-aminopyridinium) nona­vanado(V)tellurate(VI)

In the title compound, the tellurium(VI) and vanadium(V) atoms are statistically disordered over two of the ten metal-atom sites in the unprotonated [TeV9O28]5– heteropolyanion.




d

Crystal structures and circular dichroism of {2,2'-[(1S,2S)-1,2-di­phenyl­ethane-1,2-diylbis(nitrilophenyl­methanylyl­idene)]diphenolato}nickel(II) and its ethanol solvate

A chiral nickel(II) Schiff base complex derived from 2-hy­droxy­benzo­phenone and (1S,2S)-1,2-di­phenyl­ethyl­enedi­amine shows a λ conformation of the central di­amine chelate ring. The substituents on the C&z-dbnd;N carbon atoms significantly affect the circular dichroism spectra.




d

Crystal structure and Hirshfeld-surface analysis of an etoxazole metabolite designated R13

The crystal structure of a metabolite of the insecticide/acaricide etoxazole, designated R13 is presented along with a Hirshfeld surface analysis of inter­molecular inter­actions present in the crystal structure.




d

Crystal structure, Hirshfeld surface analysis, DFT and mol­ecular docking studies of ethyl 5-amino-2-bromo­isonicotinate

Theoretical and experimental structural studies of the title compound were undertaken using X-ray and DFT methods. The inter­actions present in the crystal were analyzed using Hirshfeld surface and MEP surface analysis. Docking studies with a covid-19 main protease (PDB ID: 6LU7) as the target receptor indicate that the synthesized compound may be a potential candidate for pharmaceutical applications.




d

Crystal structure of 1,10-phenanthrolinium violurate violuric acid penta­hydrate

The crystal structure of the co-crystal salt solvate 1,10-phenanthrolinium violurate violuric acid penta­hydrate features a tri-periodic hydrogen-bonded network with the violurate and violuric acid residues each assembled into tapes and the phenanthrolinium cations residing in channels.




d

Crystal structure of a solvated dinuclear CuII complex derived from 3,3,3',3'-tetraethyl-1,1'-(furan-2,5-dicarbonyl)bis(thiourea)

In the title compound, [Cu2(L)2]·2CH2Cl2, the CuII ions coordinate two (S,O)-chelating aroyl­thio­urea moieties of doubly deprotonated furan-2,5-di­carbonyl­bis­(N,N-di­ethyl­thio­urea) (H2L) ligands. The coordination geometry of the metal centers is best described as a flat isosceles trapezoid with a cis arrangement of the donor atoms.




d

Crystal structures of two polymorphs for fac-bromido­tricarbon­yl[4-(4-meth­oxy­phen­yl)-2-(pyridin-2-yl)thia­zole-κ2N,N']rhenium(I)

Crystallization of the title compound from CH2Cl2/n-pentane (1:5 v/v) at room temperature gave two polymorphs, which crystallize in monoclinic (P21/c; α form) and ortho­rhom­bic (Pna21; β form) space groups. The ReI complex mol­ecules in either polymorph adopt a six-coordinate octa­hedral geometry with three facially-oriented carbonyl ligands, one bromido ligand, and two nitro­gen atoms from one chelating ligand ppt-OMe. In the crystal, both polymorph α and β form di-periodic sheet-like architectures supported by multiple hydrogen bonds.




d

Crystal structure, Hirshfeld surface, DFT and mol­ecular docking studies of 2-{4-[(E)-(4-acetylphen­yl)diazen­yl]phen­yl}-1-(5-bromo­thio­phen-2-yl)ethanone; a bromine⋯oxygen type contact

The title compound is a non-liquid crystal mol­ecule. The mol­ecular crystal is consolidated by C—Br⋯O&z-dbnd;C type contacts running continuously along the [001] direction.




d

Synthesis, crystal structure and Hirshfeld surface analysis of N-(4-meth­oxy­phen­yl)picolinamide

The mol­ecular and crystal structure of N-(4-meth­oxy­phen­yl)picolinamide were studied and Hirshfeld surfaces and fingerprint plots were generated to investigate various inter­molecular inter­actions.