Ribozymes: Hammerhead

The hammerhead, about 40 nucleotides long, is the smallest naturally occurring ribozyme. It accompanies RNA viruses that infect plants.

The hammerhead plays a role in viral replication. It cuts up linear viral genome RNAs with tandem repeats made by the host into equal-length segments.

Because of its small size, the hammerhead was the first ribozyme whose structure was determined by X-ray crystallography.