Gene regulation by a glycine riboswitch singlet uses a finely tuned energetic landscape for helical switching

Gene regulation by a transcriptional ON switch. Depicted is an example of a glycine riboswitch type-1 singlet transcriptional ON switch. A terminator hairpin forms in the absence of ligand, which leads to termination of the mRNA upstream of the gene of interest. Ligand binding induces a structural rearrangement and stabilizes an antiterminator helix that is mutually exclusive with the terminator hairpin. This causes an increase in production of full-length mRNA and gene expression.