Cover image

Fluorescent RNA aptamer cationic chromophore complex (Chili) (PDB id: 7OA3; Mieczkowski M, Steinmetzger C, Bessi I, Lenz AK, Schmiedel A, Holzapfel M, Lambert C, Pena V, Hobartner C. 2021. Large Stokes shift fluorescence activation in an RNA aptamer by intermolecular proton transfer to guanine. Nat Commun 12: 3549). Fluorogenic RNA aptamers are synthetic functional RNAs that specifically bind and activate conditional fluorophores. The Chili RNA aptamer shown here mimics large Stokes shift fluorescent proteins and exhibits high affinity for 3,5-dimethoxy-4-hydroxybenzylidene imidazolone (DMHBI) derivatives to elicit green or red fluorescence emission. RNA backbone is displayed as a red ribbon; block bases use NDB colors: A—red, C—yellow, G—green, U—cyan; cationic chromophore is shown as spheres. Cover image provided by the Nucleic Acid Database (ndbserver.rutgers.edu). Image generated using DSSR and PyMOL (Lu XJ. 2020. Nucleic Acids Res 48: e74).