show Abstracthide AbstractRiboswitches contain structured aptamer domains that, upon ligand-binding, facilitate helical switching in their downstream expression platforms to alter gene expression. To fully dissect how riboswitches function requires a better understanding of the energetic landscape for helical switching. The sequencing data provided here were generated using SMART, a high-throughput technique for monitoring in vitro transcription termination. This dataset reveals the functional effects of all 522 single point mutants and several combinations of double mutants of the glycine riboswitch type-1 singlet from Clostridium tetani. These data highlight functionally relevant regions of the RNA and describe the energetic contributions ligand binding provides to the expression platform.