The Ribosome Functions as a Ribozyme

“The ribosome is a ribozyme”—there is no peptidyl transferase enzyme! This remarkable feature was revealed by the high-resolution crystal structure of the large subunit of the ribosome, which shows that peptidyl transfer, the reaction by which peptide bonds are made, is RNA-catalysed. (The picture shows active-site nucleotides and the tetrahedral carbon atom of a proposed reaction intermediate.) This finding elevates ribozyme catalysis to central importance in the cell, performing one of the main reactions of life processes, and may represent a kind of “molecular fossil” of an earlier RNA world.