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

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.
Source: Acta Crystallographica Section F - Category: Biochemistry Authors: Tags: RNA structure riboswitches ZTP X-ray free-electron lasers research communications Source Type: research