Structures of riboswitch RNA reaction states by mix-and-inject XFEL serial crystallography.

ABSTRACT: Riboswitches are structural RNA elements that are generally located in the 5' untranslated region of messenger RNA. During regulation of gene expression, ligand binding to the aptamer domain of a riboswitch triggers a signal to the downstream expression platform. A complete understanding of the structural basis of this mechanism requires the ability to study structural changes over time. Here we use femtosecond X-ray free electron laser (XFEL) pulses to obtain structural measurements from crystals so small that diffusion of a ligand can be timed to initiate a reaction before diffraction. We demonstrate this approach by determining four structures of the adenine riboswitch aptamer domain during the course of a reaction, involving two unbound apo structures, one ligand-bound intermediate, an

SUBMITTER: Stagno JR 

PROVIDER: S-EPMC5502819 | biostudies-literature | 2017 Jan

REPOSITORIES: biostudies-literature