Cover image

Fusibacterium ulcerans ZTP riboswitch bound to ZMP analog (PDB id: 6WZR; Tran B, Pichling P, Tenney L, Connelly CM, Moon MH, Ferre-D'Amare AR, Schneekloth JS Jr, Jones CP. 2020. Parallel discovery strategies provide a basis for riboswitch ligand design. Cell Chem Biol 27:1241–1249.e4). Bacterial riboswitches that specifically recognize 5-aminoimidazole-4-carboxamide riboside 5'-monophosphate (ZMP) and 5'-triphosphate (ZTP) regulate genes involved in folate and purine metabolism. The co-crystal structure of the Fusobacterium ulcerans ZTP riboswitch bound to a ZMP analog suggests that stacking of the pyridine moiety on a conserved riboswitch nucleobase accounts for threefold higher gene expression activity. RNA backbone is displayed as a red ribbon; lock bases use NDB colors: A—red, C—yellow, G—green, U—cyan. ZMP analog [5-amino-1-(pyridin-4-yl)-1H-imidazole-4-carboxamide] is shown as spheres. Cover image provided by the Nucleic Acid Database (ndbserver.rutgers.edu). Image generated using DSSR and PyMOL (Lu XJ. 2020. Nucleic Acids Res 48: e74).