Probing Ribosomal RNA By Electron Spectroscopic Imaging and Three-Dimensional Reconstruction

The ribosome is the protein synthetic machinery in the cell. Knowledge of the structures of ribosomal RNA (rRNA) macromolecules in situ is essential to understanding their roles in ribosome mediated protein synthesis. We are using a microanalytical technique that identifies and maps elements directly, electron spectroscopic imaging, to determine the rRNA phosphorus distributions within Escherichia coli ribosomal subunits, and to combine the two-dimensional maps into a three-dimensional elemental distribution by iterative quaternion-assisted angular reconstitution of ribosomal particles at random orientations.