The evolution of raw data archiving and the growth of its importance in crystallography.

The hardware for data archiving has expanded capacities for digital storage enormously in the past decade or more. The IUCr evaluated the costs and benefits of this within an official working group which advised that raw data archiving would allow ground truth reproducibility in published studies. Consultations of the IUCr's Commissions ensued via a newly constituted standing advisory committee, the Committee on Data.

Raw diffraction data and reproducibility.

In recent years, there has been a major expansion in digital storage capability for hosting raw diffraction datasets. Naturally, the question has now arisen as to the benefits and costs for the preservation of such raw, i.e.

Making your raw data available to the macromolecular crystallography community.

A recent editorial in the IUCr macromolecular crystallography journals [Helliwell et al. (2019), Acta Cryst. D75, 455-457] called for the implementation of the FAIR data principles.

Crystal structure of the second extracellular domain of human tetraspanin CD9: twinning and diffuse scattering.

Remarkable features are reported in the diffraction pattern produced by a crystal of the second extracellular domain of tetraspanin CD9 (deemed CD9), the structure of which has been described previously [Oosterheert (2020 ▸), , , e202000883]. CD9 crystallized in space group 1 and was twinned. Two types of diffuse streaks are observed.

launches Raw Data Letters.

A new category of articles - Raw Data Letters - is introduced to .

Implications for tetraspanin-enriched microdomain assembly based on structures of CD9 with EWI-F.

Tetraspanins are eukaryotic membrane proteins that contribute to a variety of signaling processes by organizing partner-receptor molecules in the plasma membrane. How tetraspanins bind and cluster partner receptors into tetraspanin-enriched microdomains is unknown. Here, we present crystal structures of the large extracellular loop of CD9 bound to nanobodies 4C8 and 4E8 and, the cryo-EM structure of 4C8-bound CD9 in complex with its partner EWI-F.

The non-swapped monomeric structure of the arginine-binding protein from Thermotoga maritima.

Domain swapping is a widespread oligomerization process that is observed in a large variety of protein families. In the large superfamily of substrate-binding proteins, non-monomeric members have rarely been reported. The arginine-binding protein from Thermotoga maritima (TmArgBP), a protein endowed with a number of unusual properties, presents a domain-swapped structure in its dimeric native state in which the two polypeptide chains mutually exchange their C-terminal helices.

Rigid-body motion is the main source of diffuse scattering in protein crystallography.

The origin of diffuse X-ray scattering from protein crystals has been the subject of debate over the past three decades regarding whether it arises from correlated atomic motions within the molecule or from rigid-body disorder. Here, a supercell approach to modelling diffuse scattering is presented that uses ensembles of molecular models representing rigid-body motions as well as internal motions as obtained from ensemble refinement. This approach allows oversampling of Miller indices and comparison with equally oversampled diffuse data, thus allowing the maximum information to be extracted from experiments.

Pathological macromolecular crystallographic data affected by twinning, partial-disorder and exhibiting multiple lattices for testing of data processing and refinement tools.

Twinning is a crystal growth anomaly, which has posed a challenge in macromolecular crystallography (MX) since the earliest days. Many approaches have been used to treat twinned data in order to extract structural information. However, in most cases it is usually simpler to rescreen for new crystallization conditions that yield an untwinned crystal form or, if possible, collect data from non-twinned parts of the crystal.

The science is in the data.

Understanding published research results should be through one's own eyes and include the opportunity to work with raw diffraction data to check the various decisions made in the analyses by the original authors. Today, preserving raw diffraction data is technically and organizationally viable at a growing number of data archives, both centralized and distributed, which are empowered to register data sets and obtain a preservation descriptor, typically a 'digital object identifier'. This introduces an important role of preserving raw data, namely understanding where we fail in or could improve our analyses.

Giant capsids from lattice self-assembly of cyclodextrin complexes.

Proteins can readily assemble into rigid, crystalline and functional structures such as viral capsids and bacterial compartments. Despite ongoing advances, it is still a fundamental challenge to design and synthesize protein-mimetic molecules to form crystalline structures. Here we report the lattice self-assembly of cyclodextrin complexes into a variety of capsid-like structures such as lamellae, helical tubes and hollow rhombic dodecahedra.

Raw diffraction data preservation and reuse: overview, update on practicalities and metadata requirements.

A topical review is presented of the rapidly developing interest in and storage options for the preservation and reuse of raw data within the scientific domain of the IUCr and its Commissions, each of which operates within a great diversity of instrumentation. A résumé is included of the case for raw diffraction data deposition. An overall context is set by highlighting the initiatives of science policy makers towards an 'Open Science' model within which crystallographers will increasingly work in the future; this will bring new funding opportunities but also new codes of procedure within open science frameworks.

Re-refinement of 4g4a: room-temperature X-ray diffraction study of cisplatin and its binding to His15 of HEWL after 14 months chemical exposure in the presence of DMSO.

A re-refinement of 4g4a, the room-temperature X-ray diffraction study of cisplatin and its binding to His15 of HEWL after 14 months chemical exposure in the presence of DMSO is published as an addendum to Tanley et al. [(2012), Acta Cryst. F68, 1300-1306].

Re-refinement of 4xan: hen egg-white lysozyme with carboplatin in sodium bromide solution.

A re-refinement of 4xan, hen egg-white lysozyme (HEWL) with carboplatin crystallized in NaBr solution, has been made and is published here as an addendum to Tanley et al. [(2014), Acta Cryst. F70, 1135-1142].

Accounting for partiality in serial crystallography using ray-tracing principles.

Serial crystallography generates `still' diffraction data sets that are composed of single diffraction images obtained from a large number of crystals arbitrarily oriented in the X-ray beam. Estimation of the reflection partialities, which accounts for the expected observed fractions of diffraction intensities, has so far been problematic. In this paper, a method is derived for modelling the partialities by making use of the ray-tracing diffraction-integration method EVAL.

Experiences with making diffraction image data available: what metadata do we need to archive?

Recently, the IUCr (International Union of Crystallography) initiated the formation of a Diffraction Data Deposition Working Group with the aim of developing standards for the representation of raw diffraction data associated with the publication of structural papers. Archiving of raw data serves several goals: to improve the record of science, to verify the reproducibility and to allow detailed checks of scientific data, safeguarding against fraud and to allow reanalysis with future improved techniques. A means of studying this issue is to submit exemplar publications with associated raw data and metadata.

Carboplatin binding to histidine.

Carboplatin is a second-generation platinum anticancer agent used for the treatment of a variety of cancers. Previous X-ray crystallographic studies of carboplatin binding to histidine (in hen egg-white lysozyme; HEWL) showed the partial conversion of carboplatin to cisplatin owing to the high NaCl concentration used in the crystallization conditions. HEWL co-crystallizations with carboplatin in NaBr conditions have now been carried out to confirm whether carboplatin converts to the bromine form and whether this takes place in a similar way to the partial conversion of carboplatin to cisplatin observed previously in NaCl conditions.

pH-controlled aggregation polymorphism of amyloidogenic Aβ(16-22): insights for obtaining peptide tapes and peptide nanotubes, as function of the N-terminal capping moiety.

Peptide and protein self-assembly resulting in the formation of amyloidogenic aggregates is generally thought of as a pathological event associated with severe diseases. However, amyloid formation may also provide a basis for advanced bionanomaterials, since amyloid fibrils combine unique material-like properties that make them very useful for design of new types of conducting nanowires, bioactive ligands, and biodegradable coatings as drug-encapsulating materials. The morphology of the supramolecular aggregates determines the properties and application range of these bionanomaterials.

Experiences with archived raw diffraction images data: capturing cisplatin after chemical conversion of carboplatin in high salt conditions for a protein crystal.

The archiving of raw diffraction images data is the focus of an IUCr Diffraction Data Deposition Working Group (see http://forums.iucr.org/).

Tissue-type plasminogen activator binds to Aβ and AIAPP amyloid fibrils with multiple domains.

Binding of tissue-type plasminogen activator (tPA) to amyloid and denatured proteins is reported in a number of studies. The binding site has been mapped previously to the finger domain of tPA. In this study, tPA and truncated tPA constructs, lacking the finger domain, were tested for their ability to bind to Aβ and AIAPP amyloid-like fibrils.

Experience with exchange and archiving of raw data: comparison of data from two diffractometers and four software packages on a series of lysozyme crystals.

The International Union of Crystallography has for many years been advocating archiving of raw data to accompany structural papers. Recently, it initiated the formation of the Diffraction Data Deposition Working Group with the aim of developing standards for the representation of these data. A means of studying this issue is to submit exemplar publications with associated raw data and metadata.

The structure of the FnI-EGF-like tandem domain of coagulation factor XII solved using SIRAS.

Coagulation factor XII (FXII) is a key protein in the intrinsic coagulation and kallikrein-kinin pathways. It has been found that negative surfaces and amyloids, such as Aβ fibrils, can activate FXII. Additionally, it has been suggested that FXII simulates cells and that it plays an important role in thrombosis.

A structural study of the self-assembly of a palmitoyl peptide amphiphile.

Peptide amphiphiles consisting of a hydrophobic alkyl tail coupled to the eight-amino acid GANPNAAG have been studied extensively for their fibre forming properties. However, detailed characteristics of the fibre structure, such as peptide conformation and molecular organisation, are unknown to date. In this report a range of characterization techniques is described that have been employed to elucidate the internal structure of these fibres.

Room-temperature X-ray diffraction studies of cisplatin and carboplatin binding to His15 of HEWL after prolonged chemical exposure.

The anticancer complexes cisplatin and carboplatin are known to bind to both the Nδ and the Nℇ atoms of His15 of hen egg-white lysozyme (HEWL) in the presence of dimethyl sulfoxide (DMSO). However, neither binds in aqueous media after 4 d of crystallization and crystal growth, suggesting that DMSO facilitates cisplatin/carboplatin binding to the N atoms of His15 by an unknown mechanism. Crystals of HEWL cocrystallized with cisplatin in both aqueous and DMSO media, of HEWL cocrystallized with carboplatin in DMSO medium and of HEWL cocrystallized with cisplatin and N-acetylglucosamine (NAG) in DMSO medium were stored for between seven and 15 months.