Methodologies of structural studies of protein complexes by neutron scattering and diffraction

Neutron scattering and diffraction has a specific feature that because of the large difference in the neutron scattering length of hydrogen and deuterium, the contrast of molecules against the solvent can be varied over a very wide range by changing the amount of D2O in the solvent. This 'contrast variation' method is not only applicable in the area of solution scattering but also applicable to all types of low-resolution measurements such as low-resolution neutron crystallography and neutron fiber diffraction. Combination of selective deuteration and contrast-matching in these measurements is also important particularly in structural studies of protein complexes. Methodologies of structural studies of biological macromolecules using these techniques are briefly described, with the emphasis on the applicability to ordered systems of protein complexes. (author)