Integrated, rational molecular replacement

Introducing the virtual special issue on the 2019 CCP4 Study Weekend on Integrated, rational molecular replacement at https://journals.iucr.org/special_issues/2020/CCP42019/.

Detection of translational noncrystallographic symmetry in Patterson functions

Translational noncrystallographic symmetry (TNCS) was analysed using a curated database of 80 000 protein structures to inform an algorithm for the detection of TNCS order.

The accuracy of protein models automatically built into cryo-EM maps with ARP/wARP

A new module of the ARP/wARP suite for automated model building into cryo-EM maps is presented.

IceBear: an intuitive and versatile web application for research-data tracking from crystallization experiment to PDB deposition

The IceBear web application for monitoring and recording the results of crystallization experiments is introduced. This software includes tools for interacting directly with the ISPyB synchrotron database: metadata from shipped crystals can be uploaded directly to ISPyB, and for each sample a link to the synchrotron ISPyB diffraction information becomes available in IceBear.

Structure–functional relationship of cellular retinoic acid-binding proteins I and II interacting with natural and synthetic ligands

Structures of Homo sapiens cellular retinoic acid-binding proteins I and II in the presence of natural and synthetic ligands are presented, demonstrating canonical binding activity for these new molecules and relating the structure and function of these novel retinoid signalling modulators.

Ab initio determination of the shape of membrane proteins in a nanodisc

Marbles is novel software that employs SAXS intensities to predict the shape of membrane proteins embedded into membrane nanodiscs.

Homogeneous batch micro-crystallization of proteins from ammonium sulfate

This work demonstrates how the precipitating properties of ammonium sulfate can be exploited to drive the transition from vapour-diffusion conditions to large-scale batch micro-crystallization and how the specific ammonium sulfate concentration can further be used to fine-tune microcrystal size and size distribution.

Glycoside hydrolase family 5: structural snapshots highlighting the involvement of two conserved residues in catalysis

A combined analysis using structural biology, enzymatic assays and mass spectrometry highlights the role of several conserved residues in the catalytic site of the glycoside hydrolase family 5 transglycosylase RBcel1.

Identification and characterization of two classes of G1 β-bulge

G1 β-bulges have been resolved into two subtypes that are differentiated by the dihedral angles at the position N-terminal to the doubleton. They have different amino-acid preferences and are unique constituents of higher-order protein architecture.

C-phycocyanin as a highly attractive model system in protein crystallography: unique crystallization properties and packing-diversity screening

C-phycocyanin, a photosynthetic antenna protein from the cyanobacterium Thermosynechococcus elongatus, was crystallized in hundreds of different conditions, producing protein crystals with various sizes and morphologies. Among the many diffraction data sets that were collected, high-resolution X-ray structures with novel symmetries were solved and are discussed with the aim of providing a highly adaptable experimental model system.

Crystal structures of the selenoprotein gluta­thione peroxidase 4 in its apo form and in complex with the covalently bound inhibitor ML162

The crystal structure of the human selenocysteine-containing protein glutathione peroxidase 4 (GPX4) was determined at 1.0 Å resolution. A mass-spectrometry-based approach was developed to monitor the formation of adducts of the active-site selenocysteine Sec46 with covalent inhibitors. The crystal structure of Sec46-containing GPX4 in complex with the covalent inhibitor ML162 [(S)-enantiomer] was determined at 1.54 Å resolution.

A complete Fourier-synthesis-based backbone-conformation-dependent library for proteins

A conformation-dependent library of target values for protein main-chain bond angles was determined using a variable-resolution two-dimensional Fourier analysis.

Crystal structure of fungal tannase from Aspergillus niger

The crystal structure of a fungal tannase reveals the key residues involved in catalysis and substrate binding for the first time.