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Multiwavelength Anomalous Diffraction (multiwavelength + anomalous_diffraction)
Selected AbstractsPhasing possibilities using different wavelengths with a xenon derivativeJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 2 2002Santosh Panjikar Xenon derivatives are generally expected to be isomorphous with the native; however, the K - and L -absorption edges are not easily accessible on most synchrotron beamlines, which might limit their usefulness in phase determination. Various phasing procedures for xenon-derivatized porcine pancreatic elastase have been investigated using data sets measured at three generally accessible wavelengths. The importance of highly redundant data in measuring precise anomalous differences is highlighted and it is shown that, after such measurements, a single isomorphous replacement anomalous scattering (SIRAS) procedure yields a better phase set than those generated by single anomalous scattering (SAS) or multiwavelength anomalous diffraction (MAD) procedures. [source] The X-ray crystal structure of PA1607 from Pseudomonas aureginosa at 1.9 Å resolution,a putative transcription factorPROTEIN SCIENCE, Issue 3 2007Edyta A.L. Sieminska Abstract The structure of the PA1607 protein from Pseudomonas aureginosa was determined at 1.85 Å resolution using the Se-Met multiwavelength anomalous diffraction (MAD) technique. PA1607 forms a dimer and adopts a winged-helix motif similar to the MarR family of transcription regulators, though it has an unusual dimerization profile. The DNA-binding regions and a putative metal-binding site are not conserved in PA1607. [source] Twinned crystals and anomalous phasingACTA CRYSTALLOGRAPHICA SECTION D, Issue 11 2003Zbigniew Dauter Merohedral or pseudomerohedral twinning of crystals cannot be identified from inspection of the diffraction patterns. Several methods for the identification of twinning and the estimation of the twin fraction are suitable for macromolecular crystals and all are based on the statistical properties of the measured diffraction intensities. If the crystal twin fraction is estimated and is not too close to 0.5, the diffraction data can be detwinned; that is, related to the individual crystal specimen. However, the detwinning procedure invariably introduces additional inaccuracies to the estimated intensities, which substantially increase when the twin fraction approaches 0.5. In some cases, a crystal structure can be solved with the original twinned data by standard techniques such as molecular replacement, multiple isomorphous replacement or multiwavelength anomalous diffraction. Test calculations on data collected from a twinned crystal of gpD, the bacteriophage , capsid protein, show that the single-wavelength anomalous diffraction (SAD) method can be used to solve its structure even if the data set corresponds to a perfectly twinned crystal with a twin fraction of 0.5. [source] Crystallization and preliminary X-ray diffraction analysis of a rat biliverdin reductaseACTA CRYSTALLOGRAPHICA SECTION D, Issue 9 2000Danyu Sun Biliverdin reductase (BVR) catalyzes the final step of haem degradation and converts biliverdin to bilirubin using NAD(P)H as an electron donor. This paper deals with the first crystallization and preliminary crystallographic study of recombinant rat BVR expressed in Escherichia coli. Crystals of BVR were obtained by the sitting-drop vapour-diffusion method. Using synchrotron radiation at station BL44B2 of SPring-8, Japan, BVR diffraction data were collected to 1.6,Å resolution. Crystals belong to the orthorhombic space group P212121, with unit-cell parameters a = 58.89, b = 70.41, c = 87.76,Å. The complete determination of the crystallographic structure is currently in progress using MAD (multiwavelength anomalous diffraction) data from an Ir-derivative crystal. [source] Crystallization and preliminary X-ray studies of the N-domain of the Wilson disease associated proteinACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 6 2009Lili Liu Wilson disease associated protein (ATP7B) is essential for copper transport in human cells. Mutations that affect ATP7B function result in Wilson's disease, a chronic copper toxicosis. Disease-causing mutations within the N-domain of ATP7B (WND) are known to disrupt ATP binding, but a high-resolution X-ray structure of the ATP-binding site has not been reported. The N-domain was modified to delete the disordered loop comprising residues His1115,Asp1138 (WND,1115,1138). Unlike the wild-type N-domain, WND,1115,1138 formed good-quality crystals. Synchrotron diffraction data have been collected from WND,1115,1138 at the Canadian Light Source. A native WND,1115,1138 crystal diffracted to 1.7,Å resolution and belonged to space group P42212, with unit-cell parameters a = 39.2, b = 39.2, c = 168.9,Å. MAD data were collected to 2.7,Å resolution from a SeMet-derivative crystal with unit-cell parameters a = 38.4, b = 38.4, c = 166.7,Å. The WND,1115,1138 structure is likely to be solved by phasing from multiwavelength anomalous diffraction (MAD) experiments. [source] | ||||||||||