Co-crystal structure of the Fusobacterium ulcerans ZTP riboswitch using an X-ray free-electron laser.

ABSTRACT: Riboswitches are conformationally dynamic RNAs that regulate gene expression by binding specific small molecules. ZTP riboswitches bind the purine-biosynthetic intermediate 5-aminoimidazole-4-carboxamide riboside 5'-monophosphate (ZMP) and its triphosphorylated form (ZTP). Ligand binding to this riboswitch ultimately upregulates genes involved in folate and purine metabolism. Using an X-ray free-electron laser (XFEL), the room-temperature structure of the Fusobacterium ulcerans ZTP riboswitch bound to ZMP has now been determined at 4.1?Å resolution. This model, which was refined against a data set from ?750 diffraction images (each from a single crystal), was found to be consistent with that previously obtained from data collected at 100?K using conventional synchrotron X-radiation. These experiments demonstrate the feasibility of time-resolved XFEL experiments to understand how the ZTP riboswitch accommodates cognate ligand binding.

SUBMITTER: Jones C 

PROVIDER: S-EPMC6613445 | biostudies-literature | 2019 Jul

REPOSITORIES: biostudies-literature