June 2016 issue
A significant advance in the area of nuclear transport, which also has important implications for understanding the limitations of crystallization approaches, is discussed.
Two crystal structure forms of the highly flexible HEAT-repeat protein importin-β from C. thermophilum obtained under divergent crystallization conditions revealed different conformations. SAXS experiments and the analysis of other pairs of importin-β complex structures retrieved from the Protein Data Bank suggest that an increase in the PEG present in the crystallization condition leads to a more elongated conformation of importin-β.
Crystal structures of a fragment (residues 132–251) of human Caprin-1 shed lights onto the homodimerization of Caprin-1 and its interactions with partner proteins.
Diffraction experiments were carried out at different wavelengths (1.9, 2.7, 3.0 and 3.3 Å) using lysozyme and ferredoxin reductase crystals of various sizes to investigate the influence on native SAD phasing.
Measurements of the T = 77 K glass-phase densities of drops with volumes down to 70 pl are used to determine the concentration-dependent thermal contraction of aqueous glycerol and ethylene glycol solutions. Applications in optimizing cryocrystallographic outcomes by matching the contractions of external and internal solvent to those of the crystal and internal solvent spaces are discussed.
A structure-based drug-discovery program is under way in order to identify and develop small-molecule inhibitors of S100B for the treatment of malignant melanoma. X-ray crystallographic analysis of two S100B inhibitors reveals newly identified inhibitor–target interactions within site 3 of Ca2+-bound S100B. These data contribute to the structural biology knowledge base for this target, which is important for rational drug-design efforts.
The structure determination of the NONO homodimer is reported, detailing the challenges in protein purification and identifying and overcoming overlapping reflections.
This paper presents the advantages of using the transferable aspherical atom model of macromolecular structure refinement against ultrahigh-resolution X-ray data over the classic independent-atom model approach in terms of final crystallographic statistics, the description of atomic displacement parameters and the quality of electron-density maps.
The DNA decamer d(GCATGCATGC) crystallizes in three distinct conformations on minor changes in the crystallization condition. Two different conformations (double fold and B-type helix) are present in the same unit cell.
The effect of sample impurities on SAD phasing of SFX data has been studied using simulated data. It was found that small amounts of impurities can seriously affect the results, while post-experimental purification is capable of improving the result to nearly resemble that from a pure sample.
The residues Lys271, Ser266 and Thr267 of the linker region that connects the methyltransferase and RNA-dependent RNA polymerase domains of dengue virus NS5 serotype 4 are important for differential compactness.
The structure of K. pneumoniae HpxW, an oxamate amidohydrolase, has been determined and the kinetics of the wild-type enzyme and two active-site variants have been characterized. Based on these data, a mechanism for the HpxW-catalysed reaction is proposed.
An iterative method of map recovery for perfectly merohedrally twinned crystals in the presence of noncrystallographic symmetry is reimplemented and released and an independent metric of success is provided.