Allosteric Logic of the V. vulnificus Adenine Riboswitch Resolved by Four-dimensional Chemical Mapping

摘要: The structural logic that define the functions of gene regulatory RNA molecules may be radically different from classic models allostery, but relevant correlations have remained elusive in even intensively studied model systems. Here, we present a four-dimensional expansion chemical mapping called lock-mutate-map-rescue (LM2R), which integrates multiple layers mutation with nucleotide-resolution mapping. This technique resolves core mechanism adenine-responsive V. vulnificus add riboswitch including its expression platform, paradigmatic system for both Monod-Wyman-Changeux (MWC) conformational selection and non-MWC alternatives been proposed. To discriminate amongst these models, locked each functionally important helix through designed mutations assessed formation or depletion other helices via high-throughput compensatory rescue experiments. These LM2R measurements give strong support to pre-existing predicted by MWC disfavor alternative reveal new heterogeneities general across ligand-free riboswitches.