Macromolecular crystallography at LURE: instrumentation for X-ray diffraction data collection and results

1993 ◽  
Vol 49 (s1) ◽  
pp. c11-c11
Author(s):  
R. Fourme ◽  
R. Kahn ◽  
W. Shepard ◽  
A. Beniley
Keyword(s):  
Data Collection ◽  
Diffraction Data ◽  
Macromolecular Crystallography ◽  
X Ray Diffraction ◽  
X Ray

scholarly journals Visualisation of membrane protein crystals using X-ray imaging

2014 ◽  
Vol 70 (a1) ◽  
pp. C351-C351
Author(s):  
Anna Warren ◽  
Wes Armour ◽  
Danny Axford ◽  
Mark Basham ◽  
Thomas Connolley ◽  
...  
Keyword(s):  
Data Collection ◽  
Diffraction Data ◽  
Cubic Phase ◽  
Informed Decision Making ◽  
Macromolecular Crystallography ◽  
X Ray Diffraction ◽  
Shape Estimation ◽  
X Ray ◽  
Raster Scanning ◽  
X Ray Imaging

The focus in macromolecular crystallography is moving towards even more challenging target proteins that often crystallise on much smaller scales and are frequently mounted in opaque or highly refractive materials.[1,2] It is therefore essential that X-ray beamline technology develops in parallel to accommodate such difficult samples. In this poster the use of X-ray microradiography and microtomography is reported as a tool for crystal visualisation, location and characterization on the macromolecular crystallography beamlines at the Diamond Light Source. The technique is particularly useful for microcrystals, and crystals mounted in opaque materials such as lipidic cubic phase. X-ray diffraction raster scanning can be used in combination with radiography to allow informed decision-making at the beamline prior to diffraction data collection. It is demonstrated that the X-ray dose required for a full tomography measurement is similar to a diffraction grid scan. However, for sample location and shape estimation alone, just a few radiographic projections may be required; hence reducing the dose the crystals will be exposed to prior to the diffraction data collection.[3]

scholarly journals Automated harvesting and processing of protein crystals through laser photoablation

2016 ◽  
Vol 72 (4) ◽  
pp. 454-466 ◽  
Author(s):  
Ulrich Zander ◽  
Guillaume Hoffmann ◽  
Irina Cornaciu ◽  
Jean-Pierre Marquette ◽  
Gergely Papp ◽  
...  
Keyword(s):  
Data Collection ◽  
Macromolecular Crystallography ◽  
X Ray Diffraction ◽  
X Ray ◽  
New Methods ◽  
Repeated Sample ◽  
Sample Recovery ◽  
Through Diffusion ◽  
X Ray Background ◽  
Low X

Currently, macromolecular crystallography projects often require the use of highly automated facilities for crystallization and X-ray data collection. However, crystal harvesting and processing largely depend on manual operations. Here, a series of new methods are presented based on the use of a low X-ray-background film as a crystallization support and a photoablation laser that enable the automation of major operations required for the preparation of crystals for X-ray diffraction experiments. In this approach, the controlled removal of the mother liquor before crystal mounting simplifies the cryocooling process, in many cases eliminating the use of cryoprotectant agents, while crystal-soaking experiments are performed through diffusion, precluding the need for repeated sample-recovery and transfer operations. Moreover, the high-precision laser enables new mounting strategies that are not accessible through other methods. This approach bridges an important gap in automation and can contribute to expanding the capabilities of modern macromolecular crystallography facilities.

RADDOSE-3D: time- and space-resolved modelling of dose in macromolecular crystallography

2013 ◽  
Vol 46 (4) ◽  
pp. 1225-1230 ◽  
Author(s):  
Oliver B. Zeldin ◽  
Markus Gerstel ◽  
Elspeth F. Garman
Keyword(s):  
Data Collection ◽  
Radiation Damage ◽  
Diffraction Experiment ◽  
Macromolecular Crystallography ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
X Ray ◽  
Online Methods ◽  
Crystal Volume ◽  
Number Of Iterations

RADDOSE-3D allows the macroscopic modelling of an X-ray diffraction experiment for the purpose of better predicting radiation-damage progression. The distribution of dose within the crystal volume is calculated for a number of iterations in small angular steps across one or more data collection wedges, providing a time-resolved picture of the dose state of the crystal. The code is highly modular so that future contributions from the community can be easily integrated into it, in particular to incorporate online methods for determining the shape of macromolecular crystals and better protocols for imaging real experimental X-ray beam profiles.

Masquerade: removing non-sample scattering from integrated reflection intensities

2012 ◽  
Vol 45 (2) ◽  
pp. 292-298 ◽  
Author(s):  
J. A. Coome ◽  
A. E. Goeta ◽  
J. A. K. Howard ◽  
M. R. Probert
Keyword(s):  
Data Collection ◽  
Diffraction Data ◽  
Low Temperatures ◽  
Test Case ◽  
X Rays ◽  
Atmospheric Conditions ◽  
X Ray Diffraction ◽  
New Approach ◽  
X Ray ◽  
Internal Agreement

X-ray diffraction experiments at very low temperatures require samples to be isolated from atmospheric conditions and held under vacuum. These conditions are usually maintainedviathe use of beryllium chambers, which also scatter X-rays, causing unwanted contamination of the sample's diffraction pattern. The removal of this contamination requires novel data-collection and processing procedures to be employed. Herein a new approach is described, which utilizes the differences in origin of scattering vectors from the sample and the beryllium to eliminate non-sample scattering. The programMasqueradehas been written to remove contaminated regions of the diffraction data from the processing programs. Coupled with experiments at different detector distances, it allows for the acquisition of decontaminated data. Studies of several single crystals have shown that this approach increases data quality, highlighted by the improvement in internal agreement factor with the test case of cytidine presented herein.

scholarly journals XAS at the Canadian Macromolecular Crystallography Facility

2014 ◽  
Vol 70 (a1) ◽  
pp. C1525-C1525
Author(s):  
Julien Cotelesage ◽  
Pawel Grochulski ◽  
Michel Fodje ◽  
James Gorin ◽  
Kathryn Janzen ◽  
...  
Keyword(s):  
Data Collection ◽  
Diffraction Data ◽  
Three Dimensional ◽  
Minimal Risk ◽  
Macromolecular Crystallography ◽  
X Ray ◽  
Biologically Relevant ◽  
Wide Range ◽  
X Ray Absorption ◽  
Do So

Recent additions to the Canadian Macromolecular Crystallography Facility have expanded the capabilities of its bending magnet beamline. It is now possible to perform x-ray absorption spectroscopy (XAS) on crystals. A wide range of biologically relevant metals can be further studied, supplementing diffraction data. XAS can be used to determine if metalloproteins are photoreducing during diffraction data collection. The geometries of metal complexes can also be inferred with near-edge and EXAFS data, often more accurately than crystallography. CMCF-BM can be employed to do the abovementioned techniques on powder and solution samples that contain a metal of interest. One XAS-based technique that shows promise is single crystal plane polarized EXAFS. This technique combines crystallographic data with the findings from XAS to yield a high resolution three dimensional atomic model. More recently a number of the procedural steps required for the acquisition of XAS-based data have been automated in the MxDC software suite. These changes to data collection make it easier for users new to these disciplines to run the XAS-based experiments. By having the necessary equipment to do XAS at a protein crystallography facility, researchers who may not have had the opportunity delve into the field of XAS now can do so with minimal risk in terms of materials, funds and time.

scholarly journals The finer things in X-ray diffraction data collection

1999 ◽  
Vol 55 (10) ◽  
pp. 1718-1725 ◽  
Author(s):  
J. W. Pflugrath
Keyword(s):  
Data Collection ◽  
Diffraction Data ◽  
Rotation Angle ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
Software Suite ◽  
X Ray ◽  
Position Sensitive ◽  
X Ray Background ◽  
Position Sensitive Detectors

X-ray diffraction images from two-dimensional position-sensitive detectors can be characterized as thick or thin, depending on whether the rotation-angle increment per image is greater than or less than the crystal mosaicity, respectively. The expectations and consequences of the processing of thick and thin images in terms of spatial overlap, saturated pixels, X-ray background andI/σ(I) are discussed. Thed*TREKsoftware suite for processing diffraction images is briefly introduced, and results fromd*TREKare compared with those from another popular package.

The structure of cubic MOF [{Ca(H2O)6}{CaGd(oxydiacetate)3}2].4H2O. A comparison between structural models obtained from Rietveld refinement of conventional and synchrotron X-ray powder diffraction data and standard refinement of single-crystal X-ray diffraction data

2012 ◽  
Vol 27 (4) ◽  
pp. 232-242 ◽  
Author(s):  
Leopoldo Suescun ◽  
Jun Wang ◽  
Ricardo Faccio ◽  
Guzmán Peinado ◽  
Julia Torres ◽  
...  
Keyword(s):  
Data Collection ◽  
Single Crystal ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Structural Models ◽  
Initial Time ◽  
High Symmetry ◽  
Powder Diffraction Data ◽  
X Ray Diffraction ◽  
X Ray

The structure of the metal–organic framework (MOF) compound [{Ca(H2O)6}{CaGd(oxydiacetate)3}2]·4H2O was determined by single-crystal X-ray diffraction and refined using conventional single-crystal X-ray diffraction data. In addition, the structure was refined using powder diffraction data collected from two sources, a conventional X-ray diffractometer in Bragg–Brentano geometry and a 12-detector high resolution synchrotron-based diffractometer in transmission geometry. Data from the latter were processed in three different ways to account for crystalline decay or radiation damage. One dataset was obtained by averaging the multiple detector patterns, another dataset was obtained by cutting the non-overlapping portions of each detector to consider only the first few minutes of data collection and a dose-corrected dataset was obtained by fitting the independent peaks in every dataset and extrapolating the intensity and peak position to the initial time of data collection or to zero-absorbed dose. The compared structural models obtained show that special processing of powder diffraction data produced a much accurate model, close to the single-crystal-based model for this particular compound with heavy atoms in high symmetry positions that do not contribute to a significant number of diffraction intensities.

scholarly journals A history of experimental phasing in macromolecular crystallography

2016 ◽  
Vol 72 (3) ◽  
pp. 293-295 ◽  
Author(s):  
Neil Isaacs
Keyword(s):  
Crystal Structures ◽  
Electron Density ◽  
Diffraction Data ◽  
Fourier Transforms ◽  
Macromolecular Crystallography ◽  
X Ray Diffraction ◽  
Crystal Lattices ◽  
X Ray ◽  
Experimental Phasing ◽  
History Of

It was just over a century ago that W. L. Bragg published a paper describing the first crystal structures to be determined using X-ray diffraction data. These structures were obtained from considerations of X-ray diffraction (Bragg equation), crystallography (crystal lattices and symmetry) and the scattering power of different atoms. Although W. H. Bragg proposed soon afterwards, in 1915, that the periodic electron density in crystals could be analysed using Fourier transforms, it took some decades before experimental phasing methods were developed. Many scientists contributed to this development and this paper presents the author's own perspective on this history. There will be other perspectives, so what follows isahistory, rather thanthehistory, of experimental phasing.

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