Single-molecule observations of ribosome function.

Single-molecule investigations promise to greatly advance our understanding of basic and regulated ribosome functions during the process of translation. Here, recent progress towards directly imaging the elemental translation elongation steps using fluorescence resonance energy transfer (FRET)-based imaging methods is discussed, which provide striking evidence of the highly dynamic nature of the ribosome. In this view, global rates and fidelities of protein synthesis reactions may be regulated by interactions of the ribosome with mRNA, tRNA, translation factors and potentially many other cellular ligands that modify intrinsic conformational equilibria in the translating particle. Future investigations probing this model must aim to visualize translation processes from multiple structural and kinetic perspectives simultaneously, to provide direct correlations between factor binding and conformational events.