GlmS glucosamine 6 phosphate activated ribozyme

The Glucosamine-6-phosphate activated ribozyme ( glmS ribozyme) is an RNA structure that is both a ribozyme, since it catalyzes a chemical reaction, and a riboswitch, since it regulates genes in response to concentrations of a metabolite. It was originally identified using bioinformatics in the 5' untranslated regions of glmS genes. The GlmS enzyme catalyzes the production of glucosamine-6-phosphate (GlcN6P), and the glmS ribozyme is dependent on GlcN6P to achieve catalysis of its own cleavage. This cleavage leads to the degradation of the mRNA that contains the ribozyme, and ultimately lowers production of the GlmS enzyme, encoded by the glmS gene. The GlmS enzyme catalyzes the reaction to synthesize GlcN6P, so it is not required when GlcN6P levels are already high. When GlcN6P levels are low, the ribozyme does not cleave, allowing production of the GlmS enzyme, and ultimately more GlcN6P. In fact, GlcN6P is a cofactor for the cleavage reaction, as it directly participates in the chemical reaction as an acid-base catalyst.