September 2016 issue
The first interpretable X-ray scattering data concerning lateral (radial) packing of bone collagen molecules is presented, which indicates that bone contains spatially discrete collagen microfibrils. A spatially discrete microfibril model supports structure–function-based explanations for internal fibril mineralization and for the unique pattern of collagen post-translational modifications in mineralized tissues.
Crystal structures of the metallochaperone CopM from Synechocystis sp. PCC 6803 have been solved at 1.45–2.5 Å resolution, including apo, Cu+-bound, Ag+-bound and Cu2+-bound forms. A previously functionally unknown domain was found to contain a conserved copper/silver-binding motif.
An interactive molecular-dynamics environment allows significantly improved results when rebuilding macromolecular structures into low-resolution maps. Corrections are presented to three existing structures of complement C4 in distinct functional states, all with MolProbity scores of <2 despite having resolutions lower than 3.5 Å.
The structure of the extracellular portion of interferon-γ receptor 2, a member of the class II cytokine receptors, has been solved. Bioinformatic analysis revealed independent evolutionary behaviour of both receptor domains and identified a putative binding site for interferon-γ.
A genetic algorithm is described and used to select which sub-data sets from a larger pool can be merged into a high-quality data set.
The application of the EIGER hybrid photon-counting pixel detector in macromolecular crystallography is presented. Data-collection strategies exploiting the unique features of EIGER are discussed.
The first crystal structures of a dimeric, cold-adapted β-D-galactosidase from Paracoccus sp. 32d and its complex with galactose were determined. The atypical arrangement of domains may be one of the factors that are responsible for the creation of a functional dimer of this enzyme.
A method for the more accurate refinement of small molecules and ligands in biomolecular structures is provided. Improved ligand geometry is obtained via an all-atom molecular-mechanics force field.
addenda and errata
Some key parts of the algorithm for interpretation of TLS matrices in terms of elemental atomic motions and corresponding ensembles of atomic models described in the article by Urzhumtsev et al. [(2015) Acta Cryst. D71, 1668–1683] are clarified and developed, and a reference on a wrong model is corrected.