Hairpin ribozyme



The hairpin ribozyme is a small section of RNA that can act as an enzyme known as a ribozyme. Like the hammerhead ribozyme it is found in RNA satellites of plant viruses. It was first identified in the minus strand of the tobacco ringspot virus (TRSV) satellite RNA where it catalyzes a self-cleavage reaction to process the products of rolling circle virus replication to unit-length satellite RNA. Unlike other ribozymes that cleave RNA the hairpin ribozyme does not require a metal ion for the reaction.

Structure
The structure of the hairpin ribozyme has been solved by x-ray crystallography. The minimal hairpin ribozyme structure required for self-cleavage is composed of four base paired helices, and 2 internal loops, A and B. The bond that is cleaved lies within loop A.

Species distribution
The hairpin ribozyme has been identified in only 3 plant satellite RNAs:
 * tobacco ringspot virus (TRSV)
 * chicory yellow mottle virus (CYMV)
 * arabis mosaic virus (ARMV)