Fluorescence turn-on aptamers are in vitro-evolved RNAs that strongly activate their cognate conditional fluorophores. These RNAs have emerged as counterparts to fluorescent proteins, and have been widely used in applications ranging from live imaging of cellular RNAs to small-molecule sensors. Structure determination of several fluorogenic RNAs revealed diverse architectures with idiosyncratic solutions to recognize and then restrain the photoexcited fluorophores in a planar conformation. In particular, G-quadruplexes, which provide a thermodynamically stable, planar binding surface, appear to be overrepresented in fluorogenic RNAs compared to small-molecule-binding aptamers generally. Several fluorogenic aptamers, including Broccoli, Chili, Spinach, and Squash have been evolved to activate small molecule fluorophores derived from the intrinsic fluorophore of green fluorescent protein. Beetroot is a homodimeric in vitro selected RNA that binds and activates DFAME, a conditional fluorophore derived from GFP. Here you can see a recent structure of the fluorogenic aptamer Beetroot determined by x-ray crystallography (PDB code: 8EYV)
#molecularart ... #aptamer ... #RNA ... #immolecular ... #xray ... #fluorescent
Structure rendered with @proteinimaging and depicted with @corelphotopaint
#molecularart ... #aptamer ... #RNA ... #immolecular ... #xray ... #fluorescent
Structure rendered with @proteinimaging and depicted with @corelphotopaint
