Hatchet ribozyme structure and implications for cleavage mechanism

Self-cleaving ribozymes are RNAs that catalyze position-specific cleavage of their phosphodiester backbone. The cleavage site of the newly discovered hatchet ribozyme is located at the very 5' end of its consensus secondary structure motif. Here we report on the 2.1-Å crystal structure of the hatchet ribozyme in the product state, which defines its intricate tertiary fold and identifies key residues lining the catalytic pocket. This in turn has allowed us to propose a model of the precatalytic state structure and a role in catalysis for a conserved guanine. This study therefore provides a structure-based platform toward an improved understanding of the catalytic mechanism of hatchet ribozymes.