X-ray crystallography

(redirected from X-ray structure)
Also found in: Dictionary, Medical.

X-ray crystallography,

the study of crystal structures through X-ray diffraction techniques. When an X-ray beam bombards a crystalline lattice in a given orientation, the beam is scattered in a definite manner characterized by the atomic structure of the lattice. This phenomenon, known as X-ray diffraction, occurs when the wavelength of X-rays and the interatomic distances in the lattice have the same order of magnitude. In 1912, the German scientist Max von Laue predicted that crystals exhibit diffraction qualities. Concurrently, W. Friedrich and P. Knipping created the first photographic diffraction patterns. A year later Lawrence Bragg successfully analyzed the crystalline structures of potassium chloride and sodium chloride using X-ray crystallography, and developed a rudimentary treatment for X-ray/crystal interaction (Bragg's Law). Bragg's research provided a method to determine a number of simple crystal structures for the next 50 years. In the 1960s, the capabilities of X-ray crystallography were greatly improved by the incorporation of computer technology. Modern X-ray crystallography provides the most powerful and accurate method for determining single-crystal structures. Structures containing 100–200 atoms now can be analyzed on the order of 1–2 days, whereas before the 1960s a 20-atom structure required 1–2 years for analysis. Through X-ray crystallography the chemical structure of thousands of organic, inorganic, organometallic, and biological compounds are determined every year.

Bibliography

See M. Buerger, X-Ray Crystallography (1980).

X-ray crystallography

The study of crystal structure by x-ray diffraction techniques. For the experimental aspects of x-ray diffraction See X-ray diffraction

Structurally, a crystal is a three-dimensional periodic arrangement in space of atoms, groups of atoms, or molecules. If the periodicity of this pattern extends throughout a given piece of material, one speaks of a single crystal. The exact structure of any given crystal is determined if the locations of all atoms making up the three-dimensional periodic pattern called the unit cell are known. The very close and periodic arrangement of the atoms in a crystal permits it to act as a diffraction grating for x-rays. See Crystallography

x-ray crystallography

[′eks ‚rā ‚krist·əl′äg·rə·fē]
(crystallography)
The study of crystal structure by x-ray diffraction techniques. Also known as roentgen diffractometry.
References in periodicals archive ?
Kolawole, "Synthesis and characterisation of some N-alkyl/aryl and N,N;-dialkyl/aryl thiourea cadmium (II) complexes: the single crystal X-ray structures of [[Cd[Cl.sub.2][(CS(N[H.sub.2]) x NHC[H.sub.3]).sub.2]].sub.2]n and [Cd[Cl.sub.2][(CS(N[H.sub.2]) x NHC[H.sub.2]C[H.sub.3]).sub.2]]," Polyhedron, vol.
When the X-ray structures of the compound is compared with its optimized counterpart, conformational discrepancies are observed between them.
X-ray structure analysis, which is so successful in other domains, was of little help here, since it can only be used to analyze crystals.
Gilliland, The X-ray Structure of a Ribonuclease A-Uridine Vanadate Complex at 1.3 [Angstrom] Resolution, Acta Crystallogr.
2 testing Medicor FT-41 X-ray structure menneyezeti
91b GG a diffractometer be procured with microfocus X-ray source and hybrid pixel detector to conduct X-ray structure analysis, which the X-ray structure analysis metal organic frameworks (MOFs), other complexes whose ligands and other organic compounds is used.
The current structural evidences of ChR2 is limited to 1) the 6 Ea projection map obtained by cryo-electron microscopy that contains a mixture of light (open channel) and dark (closed channel) states; and 2) the 2.3 Ea X-ray structure of the dark state of a ChR1/ChR2 chimera.
We showed with our X-ray structure of a tetranucleosome how nucleosomes could be organized in the fibre.
We have used these high-resolution X-ray structures of the target protein to guide the design of new chemicals that can specifically bind into the active site and inactivate BPL.
What they have to say about them includes native membrane protein versus yeast recombinant as demonstrated by the mitochondrial ADP/ATP carrier, the sarcoplasma calcium pump as an example of what can be learned about the function of a single protein from its various x-ray structures, two-dimensional crystallization of integral membrane proteins for electron crystallography, observing both secondary and tertiary structure in membrane protein fragments, and a critical review of general guidelines for membrane protein model building and analysis.
The two striking X-ray structures known as chimneys identified by the team appear to link the lobes in the inner regions of the Galactic Centre with the Fermi bubbles.
The structural dynamics of their actions are elusive, as our understanding relies on few X-ray structures. Comparisons of the available structures show that large re-arrangements take place between two domains during transport, with what is generally described as a rocking-bundle model .