X-ray Crystallography
X-ray Crystallography - Related Videos
02:18
X-ray Crystallography
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2020
The size of the unit cell and the arrangement of atoms in a crystal may be determined from measurements of the diffraction of X-rays by the crystal, termed X-ray crystallography. Diffraction Diffraction is the change in the direction of travel experienced by an electromagnetic wave when it encounters a physical barrier whose dimensions are comparable to those of the wavelength of the light. X-rays are electromagnetic radiation with wavelengths about as long as the distance between neighboring...
09:27
Protein Crystallization for X-ray Crystallography
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Cited by 71 •
2011
The 3-D structure of a molecule provides a unique understanding of how the molecule functions. The principal method for structure determination at near-atomic resolution is X-ray crystallography. Here, we demonstrate the current methods for obtaining three-dimensional crystals of any given macromolecule that are suitable for structure determination by X-ray crystallography.
07:55
An All-in-one Sample Holder for Macromolecular X-ray Crystallography with Minimal Background Scattering
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Cited by 4 •
2019
A novel sample holder for macromolecular X-ray crystallography along with a suitable handling protocol is presented. The system allows crystal growth, crystal soaking and in situ diffraction data collection at both, ambient and cryogenic temperature without the need of any crystal manipulation or mounting.
10:46
Production of Human Norovirus Protruding Domains in E. coli for X-ray Crystallography
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Cited by 3 •
2016
Here, we describe a method to express and purify high quality norovirus protruding (P) domains in E. coli for use in X-ray crystallography studies. This method can be applied to other calicivirus P domains, as well as non-structural proteins, i.e., viral protein genome-linked (VPg), protease, and RNA dependent RNA polymerase (RdRp).
10:39
Measurement of X-ray Beam Coherence along Multiple Directions Using 2-D Checkerboard Phase Grating
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Cited by 10 •
2016
The measurement protocol and data analysis procedure are given for obtaining transverse coherence of a synchrotron radiation X-ray source along four directions simultaneously using a single 2-D checkerboard phase grating. This simple technique can be applied for complete transverse coherence characterization of X-ray sources and X-ray optics.
FAQs
Diffraction arises because the X-ray beam interacts with the electron clouds of atoms in the ordered crystal. The resulting pattern contains information about how those atoms are arranged, even though the atoms are not observed directly. Computational analysis translates the measured pattern into an electron-density map, which researchers interpret to build an atomic model.
Atomic models can show the locations and shapes of active sites, along with how a ligand or partner fits within them. These structural details connect molecular geometry with biological function and molecular recognition. Researchers can therefore use the observed contacts and spatial relationships to investigate mechanism, evaluate binding, and guide protein engineering or drug-design studies.
A crystal structure provides a spatial framework for examining the arrangement of regions within a biomolecule and the organization of interacting macromolecules. Comparing structures or examining different molecular states can expose conformational changes, while larger assemblies reveal how components are positioned relative to one another. These observations help relate structure to cellular processes and molecular function.
The workflow begins with a crystalline sample containing a protein, nucleic acid, or another biomolecule. Researchers expose the crystal to X-rays and measure the resulting diffraction pattern. Computational methods then convert those measurements into an electron-density map, which supports construction of an atomic model. The model is interpreted for structural and functional features.
The approach can be applied to crystals of proteins, nucleic acids, and other biomolecules, provided the relevant material forms a suitable crystalline sample. This range allows investigators to study individual macromolecules as well as biologically meaningful molecular arrangements. The resulting structures can support analysis of active sites, binding interactions, conformational states, and assemblies.
In biology, researchers use X-ray crystallography to connect three-dimensional molecular structure with function. Its applications include mechanistic studies, protein engineering, and structure-guided drug design. Structures also provide benchmarks for investigating molecular recognition and cellular processes, because they show the spatial relationships underlying interactions, active-site organization, and larger macromolecular assemblies.