One Crystal Form (one + crystal_form)

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Selected Abstracts

Expression, purification, crystallization and preliminary crystallographic studies of the Enterococcus faecalis cytolysin repressor CylR2

Adelia Razeto
The expression of an exotoxin called cytolysin contributes to the virulence of Enterococcus faecalis, one of the organisms responsible for antibiotic resistant infections acquired in hospitals. The DNA-binding protein CylR2 is a transcriptional repressor of cytolysin. At a specific cell density, cytolysin triggers signaling events, which result in the dissociation of CylR2 from its DNA-binding site. CylR2 was overexpressed in Escherichia coli and purified and crystals diffracting to 1.9, were obtained in two different crystal forms. One crystal form belongs to space group P41, with unit-cell parameters a = 63.7, b = 63.7, c = 41.2,, , = , = , = 90, and the other belongs to space group P1, with unit-cell parameters a = 36.9, b = 45.0, c = 47.7,, , = 67, , = 90, , = 66. [source]

Purification, crystallization and preliminary characterization of an Eph-B2/ephrin-B2 complex

Eph receptors and their ephrin ligands are involved in various aspects of cell,cell communication during development, including those of the axon pathfinding processes in the nervous system and cell,cell interactions of the vascular endothelial cells. The recognition and binding properties of the ligand-binding domain of EphB2 receptor and the extracellular domain of ephrin-B2 have been studied and two different cocrystals of their complex have been generated. One crystal form has space group C2, diffracts to 3.5, and has unit-cell parameters a = 128, b = 88, c = 79,, , = 112. The other crystal form grows in space group P1, has unit-cell parameters a = 78, b = 78, c = 78,, , = 69, , = 75, , = 69 and diffracts to 2.7,. Structure-determination experiments using the latter form are in progress. The structure of the complex will elucidate the chemical nature of the interactions between Eph receptors and ephrins, which would create the possibility of using them as targets for structure-based anticancer-drug development. [source]

Crystallization of a 45,kDa peroxygenase/peroxidase from the mushroom Agrocybe aegerita and structure determination by SAD utilizing only the haem iron

Klaus Piontek
Some litter-decaying fungi secrete haem-thiolate peroxygenases that oxidize numerous organic compounds and therefore have a high potential for applications such as the detoxification of recalcitrant organic waste and chemical synthesis. Like P450 enzymes, they transfer oxygen functionalities to aromatic and aliphatic substrates. However, in contrast to this class of enzymes, they only require H2O2 for activity. Furthermore, they exhibit halogenation activity, as in the well characterized fungal chloroperoxidase, and display ether-cleavage activity. The major form of a highly glycosylated peroxygenase was produced from Agrocybe aegerita culture media, purified to apparent SDS homogeneity and crystallized under three different pH conditions. One crystal form containing two molecules per asymmetric unit was solved at 2.2, resolution by SAD using the anomalous signal of the haem iron. Subsequently, two other crystal forms with four molecules per asymmetric unit were determined at 2.3 and 2.6, resolution by molecular replacement. [source]

Cloning, expression, purification, crystallization and preliminary X-ray analysis of the pilus-associated sortase C from Streptococcus pneumoniae

F. Neiers
The pilus-associated sortase C from Streptococcus pneumoniae (SrtC or Srt-2) acts as a polymerase for the pilus subunit proteins RrgA and RrgB. Here, the crystallization and preliminary X-ray diffraction analysis of three crystal forms of SrtC are reported. One crystal form belongs to space group P212121, with unit-cell parameters a = 48.9, b = 96.9, c = 98.9,, , = , = , = 90. The other two crystal forms belong to space group P222, with unit-cell parameters a = 48.8, b = 97.2, c = 99.2,, , = , = , = 90 and a = 48.6, b = 96.5, c = 98.8,, , = , = , = 90, respectively. Preliminary analysis indicates the presence of two molecules in the asymmetric unit of the crystal for all three forms. [source]

Preliminary crystallographic study of the Streptococcus agalactiae sortases, sortase A and sortase C1

Baldeep Khare
Sortases are cysteine transpeptidases that are essential for the assembly and anchoring of cell-surface adhesins in Gram-positive bacteria. In Streptococcus agalactiae (GBS), the pilin-specific sortase SrtC1 catalyzes the polymerization of pilins encoded by pilus island 1 (PI-1) and the housekeeping sortase SrtA is necessary for cell-wall anchoring of the resulting pilus polymers. These sortases are known to utilize different substrates for pilus polymerization and cell-wall anchoring; however, the structural correlates that dictate their substrate specificity have not yet been clearly defined. This report presents the expression, purification and crystallization of SrtC1 (SAG0647) and SrtA (SAG0961) from S. agalactiae strain 2603V/R. The GBS SrtC1 has been crystallized in three crystal forms and the GBS SrtA has been crystallized in one crystal form. [source]