scholarly journals The Use of Connected Masks for Reconstructing the Single Particle Image from X-Ray Diffraction Data. III. Maximum-Likelihood Based Strategies to Select Solution of the Phase Problem

2018 ◽  
Vol 13 (S) ◽  
pp. t70-t83 ◽  
Author(s):  
N.L. Lunina ◽  
T.E. Petrova ◽  
A.G. Urzhumtsev ◽  
V.Y. Lunin
Keyword(s):  
Maximum Likelihood ◽  
Diffraction Data ◽  
Single Particle ◽  
Particle Image ◽  
Phase Problem ◽  
X Ray Diffraction ◽  
X Ray

scholarly journals The Use of Connected Masks for Reconstructing the Single Particle Image from X-Ray Diffraction Data. II. The Dependence of the Accuracy of the Solution on the Sampling Step of Experimental Data

2015 ◽  
Vol 10 (2) ◽  
pp. 508-525 ◽  
Author(s):  
Н.Л. Лунина ◽  
N.L. Lunina
Keyword(s):  
Experimental Data ◽  
Particle Image ◽  
Expected Improvement ◽  
Problem Solution ◽  
Phase Problem ◽  
X Ray Diffraction ◽  
Sampling Step ◽  
X Ray ◽  
X Ray Crystallography ◽  
Grid Points

Advances in the methodology of the X-ray diffraction experiments leads to a possibility to register the rays scattered by large isolated biological particles (viruses and individual cells) but not only by crystalline samples. The experiment with an isolated particle provides researchers with the intensities of the scattered rays for the continuous spectrum of scattering vectors. Such experiment gives much more experimental data than an experiment with a crystalline sample where the information is limited to a set of Bragg reflections. This opens up additional opportunities in solving underlying problem of X-ray crystallography, namely, calculating phase values for the scattered waves needed to restore the structure of the object under study. In practice, the original continuous diffraction pattern is sampled, reduced to the values at grid points in the space of scattering vectors (in the reciprocal space). The sampling step determines the amount of the information involved in solving the phase problem and the complexity of the necessary calculations. In this paper, we investigate the effect of the sampling step on the accuracy of the phase problem solution obtained by the method proposed earlier by the authors. It is shown that an expected improvement of the accuracy of the solution with the reducing the sampling step continues even after crossing the Nyquist limit defined as the inverse of the double size of the object under study.

X-ray diffraction studies of oriented lipid bilayers

1995 ◽  
Vol 73 (5-6) ◽  
pp. 209-218 ◽  
Author(s):  
J. Katsaras
Keyword(s):  
Lipid Bilayers ◽  
Diffraction Data ◽  
Phase Problem ◽  
X Ray Diffraction ◽  
Density Profiles ◽  
X Ray ◽  
Oriented Lipid Bilayer ◽  
Electron Density Profiles ◽  
Subgel Phase ◽  
Phase Phase

This brief review of the X-ray diffraction technique used to study oriented lipid bilayer systems is primarily intended to demonstrate to the nonspecialist in the lipid field the amount of detailed information that can be obtained simply by visually inspecting the diffraction pattern and making some measurements with a ruler and protractor. The information that can be extracted from X-ray diffraction data is illustrated by selected examples of our most recent work.Key words: X-ray diffraction, oriented multibilayers, electron density profiles, subgel phase, phase problem.

scholarly journals Crystallization, preliminary X-ray diffraction analysis and Patterson search of oxyhaemoglobin I from the wolf (Chrysocyon brachiurus)

1999 ◽  
Vol 55 (9) ◽  
pp. 1618-1619 ◽  
Author(s):  
A. L. S. Smarra ◽  
V. Fadel ◽  
M. Dellamano ◽  
J. R. Olivieri ◽  
W. F. de Azevedo ◽  
...  
Keyword(s):  
Maximum Likelihood ◽  
Structural Analysis ◽  
Synchrotron Radiation ◽  
Diffraction Data ◽  
Molecular Replacement ◽  
Asymmetric Unit ◽  
X Ray Diffraction ◽  
Comparative Biochemistry ◽  
X Ray ◽  
Patterson Search

Oxyhaemoglobin I isolated from the Brazilian wolf Chrysocyon brachiurus has been crystallized and X-ray diffraction data has been collected to 2.06 Å resolution using a synchrotron-radiation source. Crystals were determined to belong to the space group P212121 and preliminary structural analysis revealed the presence of one tetramer in the asymmetric unit. The structure was determined using standard molecular-replacement techniques and is currently being refined using maximum-likelihood protocols. This is the first haemoglobin isolated from a member of the Canidae family to be crystallized and it will provide further insights in the comparative biochemistry of vertebrate haemoglobins.

scholarly journals Automated identification and classification of single particle serial femtosecond X-ray diffraction data

2014 ◽  
Vol 22 (3) ◽  
pp. 2497 ◽  
Author(s):  
Jakob Andreasson ◽  
Andrew V. Martin ◽  
Meng Liang ◽  
Nicusor Timneanu ◽  
Andrew Aquila ◽  
...  
Keyword(s):  
Diffraction Data ◽  
Single Particle ◽  
X Ray Diffraction ◽  
Automated Identification ◽  
X Ray

scholarly journals High-pressure synthesis and crystal structure of the mixed-cation borate Ga4In4B15O33(OH)3

2019 ◽  
Vol 74 (4) ◽  
pp. 357-363
Author(s):  
Daniela Vitzthum ◽  
Hubert Huppertz
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
High Temperature ◽  
Diffraction Data ◽  
X Ray Diffraction ◽  
Synthesis And Crystal Structure ◽  
X Ray ◽  
Mixed Cation ◽  
High Pressure High Temperature ◽  
Pressure Synthesis

AbstractThe mixed cation triel borate Ga4In4B15O33(OH)3 was synthesized in a Walker-type multianvil apparatus at high-pressure/high-temperature conditions of 12.5 GPa and 1300°C. Although the product could not be reproduced in further experiments, its crystal structure could be reliably determined via single-crystal X-ray diffraction data. Ga4In4B15O33(OH)3 crystallizes in the tetragonal space group I41/a (origin choice 2) with the lattice parameters a = 11.382(2), c = 15.244(2) Å, and V = 1974.9(4) Å3. The structure of the quaternary triel borate consists of a complex network of BO4 tetrahedra, edge-sharing InO6 octahedra in dinuclear units, and very dense edge-sharing GaO6 octahedra in tetranuclear units.

Crystallization and preliminary x-ray diffraction data of the cryptomonad biliprotein phycocyanin-645 from a Chroomonas spec.

1984 ◽  
Vol 140 (2-3) ◽  
pp. 202-205 ◽  
Author(s):  
Walter Morisset ◽  
Werner Wehrmeyer ◽  
Tilman Schirmer ◽  
Wolfram Bode
Keyword(s):  
Diffraction Data ◽  
X Ray Diffraction ◽  
X Ray

Theoretically derived thermodynamic properties can be improved by the refinement of low-frequency modes against X-ray diffraction data

2021 ◽  
Author(s):  
Anna Agnieszka Hoser ◽  
Marcin Sztylko ◽  
Damian Trzybiński ◽  
Anders Østergaard Madsen
Keyword(s):  
Thermodynamic Properties ◽  
Dft Calculations ◽  
Diffraction Data ◽  
Molecular Crystals ◽  
Low Frequency ◽  
X Ray Diffraction ◽  
X Ray ◽  
Efficient Approach

A framework for estimation of thermodynamic properties for molecular crystals via refinement of frequencies from DFT calculations against X-ray diffraction data is presented. The framework provides an efficient approach to...

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