Chapter 4 Neutron scattering

Publisher Summary The basic principles of neutron diffraction are identical to those of X-ray diffraction. But whereas X-ray diffraction is mainly used to elucidate virus structure at atomic resolution from single crystals, the main application of neutron diffraction is to determine low-resolution structures from viral suspensions. The difference between X-rays and neutron diffraction arises from the fact that the diffraction pattern obtained with X-rays is the result of their interaction with atomic electrons, whereas that obtained with neutrons has its origin in their interaction with the atomic nucleus. Neutron scattering is a very useful method for obtaining structural information that is complementary to that obtained by electron microscopy. In favorable cases, it can show how proteins, lipids and nucleic acids are distributed inside viruses. As with all physical methods, a monodisperse sample is necessary to produce useful information and it is always better to combine that method with others: electron microscopy, X-ray diffraction at large angle, and above all good biochemical characterization.