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Updated: Jan 22, 2026
Microfluidic Chips for In Situ Crystal X-ray Diffraction and In Situ Dynamic Light Scattering for Serial Crystallography
Published on: April 24, 2018
Co-crystal structure of the Fusobacterium ulcerans ZTP riboswitch using an X-ray free-electron laser
Christopher Jones1, Brandon Tran1, Chelsie Conrad2
1Biochemistry and Biophysics Center, National Heart, Lung and Blood Institute, 50 South Drive, MSC 8012, Bethesda, MD 20892, USA.
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.
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