Study of Diffuse Scattering by Means of High Resolution Structure Images

1976 ◽  
Vol 34 ◽  
pp. 476-477
Author(s):  
Sumio Iijima ◽  
G. R. Anstis
Keyword(s):  
High Resolution ◽  
Neutron Diffraction ◽  
Diffuse Scattering ◽  
Reciprocal Space ◽  
The Other ◽  
X Ray ◽  
Actual Model ◽  
High Resolution Structure ◽  
Made In ◽  
Resolution Structure

Disorders in crystals with relatively simple structures which gave diffuse scattering have been extensively studied by X-ray or neutron diffraction methods. All these investigations were based on traditional diffraction methods and observations were made in reciprocal space (note observable diffraction intensities can be considered only in terms of interatomic vectors) and therefore the results obtained there leaves considerable ambiguity, particularly when we try to derive an actual model of the disordered crystals. A solution of this problem will be given only by knowing all atom positions in an assembly of atoms and for this case the observable diffracted intensity is given bywhere (xi,yi) and (xj,yj) represent position vectors of the i th and j th atoms with scattering factors fi and fj from an arbitrary origin. On the other hand, a crystal containing imperfections can be defined by

scholarly journals Ultra-high resolution structure of endopolygalacturonase determined by X-ray and neutron diffraction

2008 ◽  
Vol 64 (a1) ◽  
pp. C368-C369
Author(s):  
T. Shimizu ◽  
T. Nakatsu ◽  
N. Shimizu ◽  
M. Sato ◽  
K. Kurihara ◽  
...  
Keyword(s):  
High Resolution ◽  
Neutron Diffraction ◽  
X Ray ◽  
High Resolution Structure ◽  
Resolution Structure

scholarly journals High-resolution structure of the photosynthetic Mn 4 Ca catalyst from X-ray spectroscopy

2007 ◽  
Vol 363 (1494) ◽  
pp. 1139-1147 ◽  
Author(s):  
Junko Yano ◽  
Jan Kern ◽  
Yulia Pushkar ◽  
Kenneth Sauer ◽  
Pieter Glatzel ◽  
...  
Keyword(s):  
High Resolution ◽  
Spectroscopic Techniques ◽  
X Ray Diffraction ◽  
X Ray ◽  
High Resolution Structure ◽  
Resonant Raman ◽  
X Ray Absorption ◽  
Water Oxidizing Complex ◽  
S States ◽  
Resolution Structure

The application of high-resolution X-ray spectroscopy methods to study the photosynthetic water oxidizing complex, which contains a unique hetero-nuclear catalytic Mn 4 Ca cluster, is described. Issues of X-ray damage, especially at the metal sites in the Mn 4 Ca cluster, are discussed. The structure of the Mn 4 Ca catalyst at high resolution, which has so far eluded attempts of determination by X-ray diffraction, X-ray absorption fine structure (EXAFS) and other spectroscopic techniques, has been addressed using polarized EXAFS techniques applied to oriented photosystem II (PSII) membrane preparations and PSII single crystals. A review of how the resolution of traditional EXAFS techniques can be improved, using methods such as range-extended EXAFS, is presented, and the changes that occur in the structure of the cluster as it advances through the catalytic cycle are described. X-ray absorption and emission techniques (XANES and Kβ emission) have been used earlier to determine the oxidation states of the Mn 4 Ca cluster, and in this report we review the use of X-ray resonant Raman spectroscopy to understand the electronic structure of the Mn 4 Ca cluster as it cycles through the intermediate S-states.

Approaches to the High Resolution Structure of Periodic Membrane Proteins

1980 ◽  
Vol 38 ◽  
pp. 666-669
Author(s):  
J.W. Wiggins
Keyword(s):  
High Resolution ◽  
Membrane Proteins ◽  
Aqueous Media ◽  
Integral Membrane Proteins ◽  
X Ray Diffraction ◽  
Sequence Determination ◽  
X Ray ◽  
High Resolution Structure ◽  
Gain Access ◽  
Resolution Structure

Integral membrane proteins are particularly difficult to study at high resolution for several reasons. Amino acid sequence determination may be difficult because the fragmentation reagents cannot gain access to the required site, fragments are insoluble in aqueous media, or lipids are difficult to remove. X-ray diffraction studies cannot be undertaken without large enough crystals. Electron microscopy studies of the usual sort cannot be used because dehydration, negative staining, embedding, and other typical procedures are incompatible with the preservation and contrasting of the structure. Even determinations of molecular weight are made difficult by the presence of bound lipid and polysaccharide.

scholarly journals The High Resolution Structure of the Centaurus A Nucleus at 2.29 GHz and 8.42 GHz

1988 ◽  
Vol 129 ◽  
pp. 137-138
Author(s):  
D. L. Meier ◽  
D. L. Jauncey ◽  
R. A. Preston ◽  
A. K. Tzioumis ◽  
A. E. Wehrle ◽  
...  
Keyword(s):  
High Resolution ◽  
Southern Hemisphere ◽  
Significant Information ◽  
Vlbi Observations ◽  
High Resolution Structure ◽  
Made In ◽  
Resolution Structure ◽  
Centaurus A

VLBI observations of the nucleus of Centaurus A were made in April, 1982 at two frequencies with an array of five Australian radio antennas as part of the Southern Hemisphere VLBI Experiment (SHEVE). Observations were undertaken at 2.29 GHz with all five antennas, while only two were operational at 8.42 GHz. The 2.29 GHz data yielded significant information on the structure of the nuclear jet. At 8.42 GHz a compact unresolved core was detected as well.

Report on a round-robin study of diffuse X-ray scattering

1986 ◽  
Vol 19 (3) ◽  
pp. 188-194 ◽  
Author(s):  
K. Ohshima ◽  
J. Harada ◽  
M. Morinaga ◽  
P. Georgopoulos ◽  
J. B. Cohen
Keyword(s):  
High Resolution ◽  
High Intensity ◽  
Diffuse Scattering ◽  
Reciprocal Space ◽  
X Ray ◽  
Absolute Intensities ◽  
X Ray Scattering ◽  
Insertion Device ◽  
The Us ◽  
Sample Chamber

The diffuse scattering in a volume in reciprocal space from NbC0.72 was measured on an absolute scale at two synchrotron sources (in the US and in Japan) and with a high-intensity rotating-anode source (in Japan). The shape and actual absolute intensities agreed to a few percent. Special problems associated with such measurements at a synchrotron are noted, especially with an insertion device. The high resolution possible at such sources reduces the need for an evacuated sample chamber. Detailed measurements can be completed in 1–2 d, making such studies much more accessible than is possible with sealed-tube X-ray generation.

Disorder in Cyclodextrin Clathrates: X-ray Diffuse Scattering Analysis of α-Cyclodextrin Cyclopentanone Hydrate

1997 ◽  
Vol 53 (4) ◽  
pp. 673-679 ◽  
Author(s):  
G. Le Bas ◽  
J. Doucet
Keyword(s):  
Crystal Growth ◽  
Neutron Diffraction ◽  
Structure Determination ◽  
Diffuse Scattering ◽  
The Other ◽  
Water Molecules ◽  
Hydroxyl Groups ◽  
Asymmetric Unit ◽  
Orientational Disorder ◽  
X Ray

Most of the cyclodextrin clathrates display disorder, consequently the structure determination is often difficult to carry out. Previous studies by X-ray and neutron diffraction have shown that the \alpha-cyclodextrin cyclopentanone hydrate crystallizes in a channel-like structure with hexagonal P6 symmetry. Two inclusion complexes were found in the asymmetric unit; there is an orientational disorder of the guest with six positions found in one host cavity, three in the other. In addition, certain host hydroxyl groups and water molecules were found to be disordered and their disorder was correlated with the guest disorder. In this paper we investigate X-ray diffuse scattering phenomena in order to go further in the interpretation of disorder. Complicated diffuse scattering patterns revealed a variety of disorder phenomena. Some were not shown by the average structure determination. The interpretation of the results (structure in domains, supercell and vacancies) helps to explain the rotational disorder of the guest and some observed strains of the averaged structure. The description of different microstructures may be of interest for crystal growth and inclusion chemistry.

Efficient, high-throughput ligand incorporation into protein microcrystals by on-grid soaking

2020 ◽  
Author(s):  
Michael W. Martynowycz ◽  
Tamir Gonen
Keyword(s):  
High Resolution ◽  
Electron Diffraction ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Proteinase K ◽  
X Ray ◽  
X Ray Crystallography ◽  
High Resolution Structure ◽  
Efficient Uptake ◽  
Resolution Structure

AbstractA method for soaking ligands into protein microcrystals on TEM grids is presented. Every crystal on the grid is soaked simultaneously using only standard cryoEM vitrification equipment. The method is demonstrated using proteinase K microcrystals soaked with the 5-amino-2,4,6-triodoisophthalic acid (I3C) magic triangle. A soaked microcrystal is milled to a thickness of 200nm using a focused ion-beam, and microcrystal electron diffraction (MicroED) data are collected. A high-resolution structure of the protein with four ligands at high occupancy is determined. Compared to much larger crystals investigated by X-ray crystallography, both the number of ligands bound and their occupancy was higher in MicroED. These results indicate that soaking ligands into microcrystals in this way results in a more efficient uptake than in larger crystals that are typically used in drug discovery pipelines by X-ray crystallography.

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