The asymmetry and cooperativity of tandem glycine riboswitch aptamers

Glycine riboswitches are known to utilize both single aptamer and tandem aptamer architectures. The presence of a second binding site in glycine-riboswitch tandem systems raises questions regarding the individual contributions each aptamer provides toward helical switching in the expression platform. The sequencing dataset presented here was collected by SMARTT (Sequencing-based Mutational Analysis of RNA Transcription Termination), a sequencing-based high-throughput assay that monitors the in vitro transcription termination efficiencies of individual mutant constructs as a function of ligand concentration. This dataset reveals the functional effects of 684 single point mutants of the tandem glycine riboswitch from Bacillus subtilis, both in the context of the wild-type construct and in the background of binding site mutations that selectively restrict ligand binding to either the first or second aptamer. Despite the known structural symmetry of tandem glycine aptamers, these data reveal an asymmetry between the contributions each aptamer provides toward helical switching. The dataset also defines the circumstances under which cooperativity in the ligand response of tandem glycine riboswitches is observed.