Abstract
A unique catalytic riboswitch resides in the 5'‐untranslated region of the
glmS
messenger RNA of numerous Gram‐positive bacteria. The
glmS
mRNA encodes the GlmS enzyme, which catalyzes a reaction that produces Glucosamine‐6‐Phosphate (GlcN6P), an essential component of the bacterial cell wall. The
glmS
riboswitch selectively recognizes and is activated by the metabolite GlcN6P. The binding of GlcN6P initiates an internal phosphoester transfer reaction that results in self‐cleavage and inactivation of the mRNA, thereby designating this riboswitch as a ribozyme. The
glmS
riboswitch stands out among the known classes of riboswitches as the only member with intrinsic catalytic capability, and similarly, the
glmS
ribozyme stands out among the known classes of natural RNA catalysts as the only ribozyme requiring a coenzyme for activity. This review will highlight the details of this uniquely coenzymedependent ribozyme, with great attention to the multifunctional aspects of the GlcN6P coenzyme.