Glucosamine-6-phosphate riboswitch ribozyme (glmS ribozyme)

The **glucosamine-6-phosphate riboswitch ribozyme** (glmS ribozyme) is a catalytic RNA motif found in the 5′ untranslated region (UTR) of the mRNA encoding **glucosamine-6-phosphate synthetase** (GlmS), predominantly in Gram-positive bacteria[1][2][6][7]. This ribozyme uniquely combines characteristics of both a **riboswitch** (an RNA element that senses metabolite concentrations and alters gene expression) and a **ribozyme** (an RNA molecule with catalytic activity)[1][6]. It acts as a metabolite-activated, self-cleaving RNA, using the product of its own regulated gene (**glucosamine-6-phosphate; GlcN6P**) as a cofactor to trigger mRNA cleavage[1][2][3][5][7][8]. The result is negative feedback: when cellular GlcN6P is abundant, glmS ribozyme cleaves its host mRNA, reducing GlmS enzyme production and thus GlcN6P synthesis further[1][3][6]. Structurally, the ribozyme forms a compact tertiary structure with multiple pseudoknots and specifically binds GlcN6P, which acts in acid-base catalysis during RNA cleavage[1][3][5]. The ribozyme pre-folds into its active state before ligand binding, and GlcN6P does not induce gross conformational change, acting more as a true coenzyme than a classical allosteric ligand[1][3][5]. The glmS ribozyme is a well-established model for co-transcriptional gene regulation and is a potential target for novel antibiotics aimed at disrupting bacterial cell wall synthesis by interfering with mRNA stability of essential genes[4][7][6]. No clinically approved drugs directly target the glmS ribozyme, but inhibitors could, in theory, disrupt its regulatory feedback loop and impair bacterial viability, making it a candidate for antibacterial drug development[4][7].

Other names

glmS ribozymeglmS riboswitchGlmS glucosamine-6-phosphate activated ribozyme

Ligand-activated self-cleavage: The small molecule metabolite **glucosamine-6-phosphate** (GlcN6P) acts as a cofactor to trigger site-specific RNA self-cleavage, leading to mRNA degradation and decreased protein synthesis[1][2][3][4][7][8].