What Are Ribozymes?

First off, what is a ribozyme? Well ribozymes are RNA molecules that are able to catalyze chemical reactions. Up until the 1980s, scientists thought all biological catalysts were proteins. But then it was discovered that some RNA molecules can act as enzymes; meaning that they can catalyze covalent changes in the structure of substrates. However, since their discovery there has been intense research in learning about the structure and activity of ribozymes.

(The image above is the crystal structure of a full-length hammerhead ribozyme. Image A is a schematic diagram, while image B is a ribbon diagram.)

Among RNA molecules, the large ribozymes, mainly groups I and II introns (nucleotide sequence within a gene that is removed by RNA splicing to generate the final mature RNA product of a gene) and RNase P (ribonuclease P, which is a catalyst found in bacterium), are of special importance. Why? Well these three groups of ribozymes show a significant requirement for metal ions in order to establish the active tertiary structure that enables catalysis. The primary role of metal ions to screen the negative charge associated with the phosphate sugar backbone.

Article:

Multiple roles of metal ions in large ribozymes.