New perspectives in biological crystallography

Biological crystallography has never been more vibrant. Celebrating this, IUCrJ invites high-impact papers from across the whole spectrum of structural biology and medicine.

Serial crystallography using synchrotron radiation

A brief history is given of how X-ray diffraction data from crystals have been recorded. Today there are new possibilities, spawned by the availability of free electron lasers that produce powerful femtosecond long X-ray pulses.

Serial crystallography on in vivo grown microcrystals using synchrotron radiation

The structure solution of T. brucei cathepsin B from 80 in vivo grown crystals with an average volume of 9 µm³ obtained by serial synchrotron crystallography at a microfocus beamline is reported.

Femtosecond X-ray diffraction from two-dimensional protein crystals

Bragg diffraction achieved from two-dimensional protein crystals using femtosecond X-ray laser snapshots is presented.

The structure of a purple acid phosphatase involved in plant growth and pathogen defence exhibits a novel immunoglobulin-like fold

The plant purple acid phosphatase PPD1 forms a novel hexameric structure with a fibronectin III-like domain that is involved in DNA selectivity, binding and activation. The degradation of DNA by PPD1 implies a role for PPD1 in plant growth and repair and in pathogen defence.

Anharmonicity and isomorphic phase transition: a multi-temperature X-ray single-crystal and powder diffraction study of 1-(2′-amino­phenyl)-2-methyl-4-nitro­imidazole

Multi-temperature single-crystal and powder diffraction experiments on 1-(2′-aminophenyl)-2-methyl-4-nitroimidazole show that this crystal undergoes an isomorphic phase transition with the coexistence of two phase domains over a wide temperature range. The anharmonic approach was the only way to model the resulting disorder.

The enrichment ratio of atomic contacts in crystals, an indicator derived from the Hirshfeld surface analysis

An enrichment ratio is derived from the decomposition of the crystal contact surface between pairs of interacting chemical species. The propensity of different contact types to form is investigated.

Structural insight into activity enhancement and inhibition of H64A carbonic anhydrase II by imidazoles

Human carbonic anhydrases are zinc metalloenzymes that catalyze the hydration and dehydration of CO₂ and HCO₃⁻, respectively. X-ray crystal structures of a variant of human carbonic anhydrase II in complex with four imidazole derivatives (imidazole, 1-methylimidazole, 2-methylimidazole and 4-methylimidazole) have been determined in order to identify the binding sites for such compounds, and a mechanism to explain the effects on catalytic activity is proposed.

Acemetacin cocrystals and salts: structure solution from powder X-ray data and form selection of the piperazine salt

Multi-component crystals of the anti-inflammatory drug acemetacin were prepared by melt crystallization and their X-ray crystal structures solved using single-crystal and high-resolution powder X-ray diffraction (PXRD) data. The acemetacin–para-aminobenzoic acid adduct and the acemetacin piperazine salt are stable to hydration in the aqueous medium (up to 24 h).