Department of Molecular Biophysics and Biochemistry, Yale University, 260 Whitney Ave, New Haven, CT 06520-8114, USA.
The peptidyl transferase center of the ribosome is literally the mother of all protein enzymes, yet it was only recently that the content of its active site was found to be RNA and not protein. This review focuses on how this RNA enzyme orients its substrates and promotes the chemical reaction that is center stage in protein synthesis.