TY  - JOUR
A1  - Steinmetzger, Christian
A1  - Bessi, Irene
A1  - Lenz, Ann-Kathrin
A1  - Höbartner, Claudia
T1  - Structure-fluorescence activation relationships of a large Stokes shift fluorogenic RNA aptamer
T2  - Nucleic Acids Research
N2  - The Chili RNA aptamer is a 52 nt long fluorogen-activating RNA aptamer (FLAP) that confers fluorescence to structurally diverse derivatives of fluorescent protein chromophores. A key feature of Chili is the formation of highly stable complexes with different ligands, which exhibit bright, highly Stokes-shifted fluorescence emission. In this work, we have analyzed the interactions between the Chili RNA and a family of conditionally fluorescent ligands using a variety of spectroscopic, calorimetric and biochemical techniques to reveal key structure - fluorescence activation relationships (SFARs). The ligands under investigation form two categories with emission maxima of ~540 nm or ~590 nm, respectively, and bind with affinities in the nanomolar to low-micromolar range. Isothermal titration calorimetry was used to elucidate the enthalpic and entropic contributions to binding affinity for a cationic ligand that is unique to the Chili aptamer. In addition to fluorescence activation, ligand binding was also observed by NMR spectroscopy, revealing characteristic signals for the formation of a G-quadruplex only upon ligand binding. These data shed light on the molecular features required and responsible for the large Stokes shift and the strong fluorescence enhancement of red and green emitting RNA-chromophore complexes.
KW  - Chili RNA Aptamer
KW  - fluorogen-activating RNA aptamer (FLAP)
KW  - Stokes-shifted fluorescence emission
KW  - key structure - fluorescence activation relationships (SFARs)
KW  - ligand binding
Y1  - 2019
UR  - https://opus.bibliothek.uni-wuerzburg.de/frontdoor/index/index/docId/19234
UR  - https://nbn-resolving.org/urn:nbn:de:bvb:20-opus-192340
ER  -