Small but mighty: the power of microcrystals in structural biology

Developments in macromolecular crystallography now allow the use of microcrystals for structural analysis through advanced beamlines and techniques such as microcrystal electron diffraction and room-temperature crystallography. This review addresses methods of matching microcrystal preparation and sample delivery. The use of microcrystals enhances the possibilities in fields such as time-resolved crystallography.

Prospects for coherent X-ray diffraction imaging at fourth-generation synchrotron sources

A review of plane-wave coherent X-ray diffraction imaging in small-angle X-ray scattering geometry is presented, together with a discussion of the new opportunities offered by fourth-generation synchrotron sources.

Code dependence of calculated crystalline electron densities. Possible lessons for quantum crystallography

The development of quantum crystallography depends on the availability of reliable theoretical electron densities. This work demonstrates a non-negligible code dependence of these densities and warns against their blind use.

Peptide bonds revisited

High-resolution crystal structures reveal that peptide bonds in α-helices exhibit a slightly more pronounced enol-like character than those in β-strands. This can go as far as peptide oxygen atoms in protein structures being protonated.

Solid-state calculations for iterative refinement in quantum crystallography using the multipole model

This work presents a new iterative refinement method, comparable to Hirshfeld atom refinement, using the Hansen–Coppens multipole model charge density description to obtain accurate atomic coordinates and atomic displacements based on CRYSTAL17 periodic boundary calculations. The refinement, performed using the Python code ReCrystal, allows the user to explore the full periodic charge density in the crystalline solid state for charge density analysis of weak interactions.

The origin of synthons and supramolecular motifs: beyond atoms and functional groups

This study establishes that hydrogen-, halogen- and chalcogen-bonding intermolecular and non-covalent intramolecular interactions are driven by a face-to-face orientation of electrophilic (charge-depleted) and nucleophilic (charge-concentrated) regions, which is the origin of the specific geometries found in synthons and supramolecular motifs.