7] Neutron-scattering topography of proteins of the small ribosomal subunit

Abstract

Publisher Summary This chapter describes the low-angle neutron scattering methods to determine the three-dimensional configuration of the proteins of the 30S ribosomal subunit of E. coli . The basic strategy for data collection and analysis has been discussed in this chapter. The chapter also concentrates on improvements in biochemical methods, instrumentation, and data analysis. Scattered intensities and transmissions are measured for the various labeled samples, buffer, empty cell, and blocked-beam background. The raw data for each of these measurements exist as two-dimensional arrays representing the number of counts in each detector element. This chapter presents a schematic diagram of data collection and analysis for measurement of inters protein distances by neutron diffraction. Data inputs include transmission measurements, radially averaged scattered intensifies, and ribosome concentrations. Difference programs calculate interference functions. Sine-Fourier inversion of interference functions to obtain P(r) distribution functions follows. Finally, a large set of the P(r) second moments is used as input to mapping programs to obtain centroid coordinates and the radius of gyration of each small subunit protein.