The glnA RNA motf, or glutamine riboswitch, was identified by bioinformatics as a conserved RNA-like structure located upstream of the glutamine synthetase gene glnA and other genes involved in the nitrogen metabolism in a variety of lineages of cyanobacteria, as well as some phages that infect cyanobacteria [20230605]. The glnA RNA motif functions as a metabolite-sensing riboswitch, which binds directly to L-glutamine [21282981]. Thus, the glnA riboswitches sense glutamine concentrations in order to measure overall nitrogen availability, and regulate the downstream genes appropriately.