Acta Crystallographica Section F – another home for cryo-electron microscopy contributions

Two of the Acta Cryst. F editors introduce a number of articles on cryo-electron microscopy.

Visualization of biological macromolecules at near-atomic resolution: cryo-electron microscopy comes of age

Transformational advances in transmission electron microscopy at cryogenic temperature (cryo-EM) is enabling atomic-level insight into the three-dimensional structure and therefore the function of biological macromolecules in solution. Contemporary cryo-EM promises to resolve problems in structural biology that were intractable just a few years ago.

On cross-correlations, averages and noise in electron microscopy

The influence of noise on cross-correlations is revisited. Equations are provided describing the influence of noise on the cross-correlations between single images and averaged images and on those between averaged images.

Survey of the analysis of continuous conformational variability of biological macromolecules by electron microscopy

In this paper, the existing image-processing approaches in electron microscopy for the analysis of continuous conformational changes of biological macromolecules are reviewed.

Single-particle reconstruction statistics: a diagnostic tool in solving biomolecular structures by cryo-EM

To consistently obtain high-resolution cryo-EM structures, the factors influencing single-particle reconstruction need to be understood. Statistics calculated during reconstruction provide a diagnostic tool to assess the amount of data that is required and whether micrograph quality needs to be improved.

Never too late for endothelin

An article detailing a structure determination that has been years in the making appears in this months issue of Acta Cryst. F. McPherson and Larson report the structure of the 21-amino acid, human peptide hormone endothelin 1 that was determined using data collected in 1992.

The X-ray crystal structure of human endothelin 1, a polypeptide hormone regulator of blood pressure

The structure of endothelin in the unbound state has been determined using X-ray diffraction data that were collected in 1992. The crystals exhibit higher symmetry than is in fact present, and they are significantly twinned. There is a dimer containing a pseudo-twofold axis in the asymmetric unit.

The structure and activity of the gluta­thione reductase from Streptococcus pneumoniae

The three-dimensional crystal structure of the glutathione reductase from Streptococcus pneumoniae is reported at 2.56 Å resolution.

The redefined DNA-binding domain of human xeroderma pigmentosum complementation group A: production, crystallization and structure solution

The redefined DNA-binding domain (residues 98–239) of human xeroderma pigmentosum complementation group A, a scaffold protein that plays significant roles in DNA-damage verification and recruiting downstream endonucleases to facilitate the repair of DNA lesions in nucleotide-excision repair, was produced and crystallized and its structure was solved.

AtNPR4 from Arabidopsis thaliana: expression, purification, crystallization and crystallographic analysis

NPR4 has been shown to be a key regulator of the salicylic acid-mediated signal perception and transduction pathways. This project aimed to obtain structural details of NPR4, thus elucidating the molecular mechanism of salicylic acid perception and its signalling role in the systemic acquired resistance pathway.