Improvements in X-ray scattering data handling and their application to the 5S rRNA structure determination

Improved data correction and evaluation methods for removing the scattering of aggregates by a sampling extrapolation formula, for smoothing by frequency filtering, combination of scattering curves registered with different diffractometers, Fourier transformations with error propagation and the interpretation of the model resolution function render it possible to determine the structural parameters and the shape of macromolecules with high precision. The largest dimensions of the prokaryotic and eukaryotic ribosomal 5S RNA molecules from E. coli and rat liver were measured to be 10.8 +- 0.6 nm and 10.9 +- 0.8 nm and the radii of gyration, 3.31 +- 0.05 nm and 3.42 +- 0.06 nm. The idendity of the shapes of both molecules was proved within a resolution of 1 nm. (author)