What is X-ray Crystallography and how it helps to study structure of COVID 19 protein

 

X-ray crystallography is a tool used for determining the atomic and molecular structure of a crystal. The underlying principle is that the crystalline atoms cause a beam of X-rays to diffract into many specific directions 

                High-resolution capsid structure can be obtained from the diffraction pattern                         generated by crystals of the virus particles (eg, human rhinovirus

 

 By measuring the angles and intensities of these diffracted beams, a crystallographer can produce a 3D picture of the density of electrons within the crystal. From this electron density image, the mean positions of the atoms in the crystal can be determined, as well as their chemical bonds, their disorder, and various other information. The method revealed the structure and function of many biological molecules, including vitamins, drugs, proteins, and nucleic acids, such as DNA. 

 Researchers at the lab grow protein crystals of a virus — just portions of the virus — and then cool those crystals using liquid nitrogen. Those crystals are sent off to Argonne National Laboratory in Lamont, Illinois, where they'll be bombarded with X-rays along a beamline inside the Advanced Photon Source, which is a particular kind of particle accelerator called a synchrotron.

The scattering of X-rays by the crystal can be measured to determine the atomic structure of whatever is being evaluated.

covid 19 structure

X-ray crystallography is a method used for various materials in the crystallized state to determine the arrangement of atoms within a crystal. Three-dimensional structure and function of many biological molecules, including proteins and nucleic acids can be discovered by this method. The crystals of a pure protein are exposed to X-ray beam and X-ray is diffracted by atoms present in a protein crystal. Depending on the organization of atoms within a crystal and the number of electrons in the atoms, an X-ray beam is diffracted into many specific directions.