October 2009 issue
The crystal structure of human dual-specificity phosphatase 14, DUSP14 (MKP6), in complex with a phosphate ion has been determined and refined to 1.88 Å resolution.
APS kinase from Thiobacillus denitrificans contains an inactive N-terminal ATP sulfurylase domain. The structure presented unveils the first hexameric assembly for an APS kinase, and reveals that structural changes in the N-terminal domain disrupt the ATP sulfurylase active site thus prohibiting activity.
New classes of helix–helix interactions in protein structures are reported in which interactions only occur at the terminal regions or between the terminal region of one helix and the middle region of another helix.
The charge balance and hydrogen-bonding network at the core of the insulin T6 hexamer have been investigated by neutron diffraction analysis at 2.1 Å resolution.
The application of a multivariate likelihood function to a single isomorphous replacement with anomalous scattering experiment improves phasing and automated model building with iterative refinement in the test cases shown.
The effects of commonly encountered impurities on various membrane-protein crystallization regimes are investigated and it is found that the lipidic cubic phase crystallization methodology is the most robust, tolerating protein contamination levels of up to 50%, with little effect on crystal quality. If generally applicable, this tolerance may be exploited (i) in initial crystallization trials to determine the `crystallizability' of a given membrane-protein and (ii) to subject partially pure membrane-protein samples to crystallization trials.
A new software system for automated ligand coordinate and restraint generation is presented.
The crystal structure of PCNA from the halophilic archaeon H. volcanii reveals specific features of the charge distribution on the protein surface that reflect adaptation to a high-salt environment and suggests a different type of interaction with DNA in halophilic PCNAs.
The combination of molecular replacement and single-wavelength anomalous diffraction improves the performance of automated structure determination with Auto-Rickshaw.
The structures of five forms of D-alanine-D-alanine ligase from T. thermophilus HB8 showed a cumulative conformational change of the molecular structure through the induced rotation of the central domain in concert with a local conformational change of three loops. The active-site structures shed light on the catalytic mechanism and the roles of the conformational change.
A new algorithm that automatically models discrete heterogeneity in X-ray data demonstrates that the variability observed at high resolution can be adequately represented by including correlated structural features in protein models. The algorithm is based on simultaneous exploration of a very large number of alternative interpretations of electron-density maps.
The crystal structure of tear lipocalin determined in space group P21 revealed large structural deviations from the previously solved X-ray structure in space group C2, especially in the loop region and adjoining parts of the β-barrel which give rise to the ligand-binding site. These findings illustrate a novel mechanism for promiscuity in ligand recognition by the lipocalin protein family.