W0066

Structural Studies of Biological Macromolecules: The Unique Role of Small Angle Neutron Scattering. Susan Krueger, NIST Center for Neutron Research, NIST, Gaithersburg, MD  20899.

Since neutrons are sensitive to the positions of the light elements such as H, C, N and O, which are of central importance to all biological systems, small-angle neutron scattering (SANS) can provide unique information on the structure and function of biological macromolecules in solution. Particularly powerful is the contrast variation technique, in which the isotopic substitution of D for H is routinely used to change the scattering from a macromolecule without affecting its biochemistry. The technique is extremely effective for the study of structural changes upon binding of nucleotides, lipids, peptides or ligands, since the scattering from one component can be separated from that of the other, providing unique structural information about each component individually, as it is interacting with the other in the complex. This talk will focus on the unique role of SANS in the study of macromolecular structure and function. The experimental methods that allow this information to be obtained will be described and examples of recent experiments using the contrast variation technique will be presented.