issue contents
November 2007 issue
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Cover illustration: Enzymatic product traffic in Torpedo californica acetylcholinesterase was studied by combining temperature-controlled kinetic crystallography and cryophotolysis of `caged' arsenocholine. The conformational changes observed increased the active-site gorge volume and opened an alternative `backdoor' exit (p. 1115).
research papers
A kinetic crystallography strategy aimed at structurally addressing the issue of product traffic in acetylcholinesterase is presented in which UV-laser-induced cleavage of a photolabile precursor of the enzymatic product analogue arsenocholine, `caged' arsenocholine, is performed in a temperature-controlled X-ray crystallography regime.
A statistical model that takes experimental errors into account allows improved estimates of the twinning fraction in merohedrally (or pseudo-merohedrally) twinned macromolecular crystals.
X-ray diffraction reflection profiles from crystals of E. coli β-galactosidase that were repeatedly cycled between 100 K and room temperature were measured at both temperatures. Domain analysis showed cooling-induced crystal damage that recovered to a large degree with warming, although there were irreversible effects, primarily from radiation exposure.
The crystal structure of a serine-specific tRNA acceptor-stem microhelix, the binding site for the seryl-tRNA synthetase, was solved by X-ray analysis.
PDB reference: tRNASer acceptor stem, 2v6w, r2v6wsf
Conformation families were determined for dipeptidic, tripeptidic, tetrapeptidic and pentapeptidic fragments. Statistical weights were calculated for the conformation families.
Y. pestis 6-hydroxymethyl-7,8-dihydropterin pyrophosphokinase (HPPK) has been characterized both structurally and biochemically.
PDB reference: Y. pestis HPPK, 2qx0, r2qx0sf
The complete structure (including H atoms) of photoactive yellow protein has been determined in D2O-soaked crystals through the application of joint X-ray (1.1 Å) and neutron (2.5 Å) structure refinement in combination with cross-validated maximum-likelihood simulated annealing.
PDB reference: photoactive yellow protein, 2qws, r2qwssf
This manuscript describes the first structures of ABC transport-system components from the pathogenic bacterium Y. pestis. These structures have allowed a comparison of the interactions between periplasmic binding proteins and their cognate transmembrane domains.
short communications
Open
access
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Modelling deformation electron density using interatomic scatters is simpler than multipolar methods, produces comparable results at subatomic resolution and can easily be applied to macromolecules.
A crystal structure of SHP-corepressor-derived LxxLL-like motif with androgen receptor (AR) ligand binding domain reveals the details of SHP-AR interaction.
PDB reference: AR LBD with SHP peptide NR Box 2, 2z4j, r2z4jsf