Neutron Scattering - the Basics

Jill Trewhella
School of Molecular and Microbial Biosciences, University of Sydney, Australia

The scattering of neutrons or X-rays by macromolecules in solution gives rise to small-angle scattering patterns that provide information about the size and shape of the scattering molecule. While there are common underlying principals and methods for extracting this information from neutron or X-ray scattering data, there are important differences in the way X-rays and neutron are produced and in how they interact with matter that can be capitalized on. X-ray sources are inherently more intense than neutron sources and hence require smaller samples and offer greater potential in time-resolved studies. On the other hand, there can be large isotope effects in neutron scattering resulting from the fact that they are scattered by the nuclei in the sample. Isotopic substitution can therefore provide a means to manipulate the neutron scattering signal from an object (contrast variation) without changing its elemental composition. This presentation will describe the basics of neutron scattering, emphasizing how the unique properties of neutrons can be capitalized on to study the structures of the components within macromolecular complexes and assemblies. Contrast variation and solvent matching experiments will be described as well as the methods for analyzing these data sets along with the limitations and strengths of different approaches (1). Examples of how neutron scattering complements and extends what is learned from high resolution techniques and from X-ray scattering will be drawn from our studies of bio-molecular signalling and regulation, specifically looking at the protein interactions controlling bacterial sporulation (2) and more recently in those involved in cardiac muscle function (3).

Whitten, A. E., Cai, S., and Trewhella, J. (2008) MULCh: ModULes for the Analysis of Small-angle Neutron Contrast Variation Data from Biomolecular Complexes. J. Appl. Cryst. 41, 222-226

Whitten, A. E., Jacques, D. A., Hammouda, B., Hanley, T., King, G. F., Guss, J. M., Trewhella, J. and Langley, D. B. (2007) The Structure of the Sda-KinA Complex Suggests an Allosteric Mechanism of Histidine Kinase Inhibition. J. Mol. Biol. 368, 407-420

Jeffries, C. M., Whitten, A. E., Harris, S. P., and Trewhella, J. (2008) Small-Angle X-ray Scattering Reveals the N-terminal Domain Organization of Myosin Binding Protein C. J. Mol. Biol. 377, 1186-1199

Date/time: Sunday, 19 October, 11:00