Spinach is an in vitro-selected RNA aptamer that binds a GFP-like ligand and activates its green fluorescence. Spinach is thus an RNA analog of GFP and has potentially widespread applications for in vivo labeling and imaging. We used antibody-assisted crystallography to determine the structures of Spinach both with and without bound fluorophore at 2.2-A and 2.4-A resolution, respectively. Spinach RNA has an elongated structure containing two helical domains separated by an internal bulge that folds into a G-quadruplex motif of unusual topology. The G-quadruplex motif and adjacent nucleotides comprise a partially preformed binding site for the fluorophore. The fluorophore binds in a planar conformation and makes extensive aromatic stacking and hydrogen bond interactions with the RNA. Our findings provide a foundation for structure-based engineering of new fluorophore-binding RNA aptamers.
A G-quadruplex-containing RNA activates fluorescence in a GFP-like fluorophore.,Huang H, Suslov NB, Li NS, Shelke SA, Evans ME, Koldobskaya Y, Rice PA, Piccirilli JA Nat Chem Biol. 2014 Jun 22. doi: 10.1038/nchembio.1561. PMID:24952597[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
↑ Huang H, Suslov NB, Li NS, Shelke SA, Evans ME, Koldobskaya Y, Rice PA, Piccirilli JA. A G-quadruplex-containing RNA activates fluorescence in a GFP-like fluorophore. Nat Chem Biol. 2014 Jun 22. doi: 10.1038/nchembio.1561. PMID:24952597 doi:http://dx.doi.org/10.1038/nchembio.1561
