TY - JOUR AB - Nucleic acids can adopt non-duplex topologies such as G-quadruplexes in vitro. Yet it hasbeen challenging to establish their existence and function in vivo due to a lack of suitabletools. Recently, we identified the triangulenium compound DAOTA-M2 as a uniquefluorescence probe for such studies. This probe’s emission lifetime is highly dependent onthe topology of the DNA it interacts with opening up the possibility of carrying out live cellimaging studies. Herein we describe the origin of its fluorescence selectivity for Gquadruplexes.Cyclic voltammetry predicts that the appended morpholino groups can act asintra-molecular photo-induced electron transfer (PET) quenchers. Photophysical studies showthat a delicate balance between this effect and inter-molecular PET with nucleobases is key tothe overall fluorescence enhancement observed upon nucleic acid binding. We utilisedcomputational modelling to demonstrate a conformational dependence of intra-molecularPET. Finally, we performed orthogonal studies with a triangulenium compound where themorpholino groups were removed and demonstrate that this change inverts trianguleniumfluorescence selectivity from G-quadruplex to duplex DNA, thus highlighting the importanceof fine-tuning the molecular structure not only for target affinity but also for fluorescenceresponse. AU - Vilar,Compte R AU - Shivalingam,A AU - Vysniauskas,A AU - Albrecht,T AU - White,AJ AU - Kuimova,MK DO - 10.1002/chem.201504099 EP - 4139 PY - 2016/// SN - 0947-6539 SP - 4129 TI - Trianguleniums as optical probes for G-quadruplexes: A photophysical, electrochemical and computational study T2 - Chemistry - A European Journal UR - http://dx.doi.org/10.1002/chem.201504099 UR - http://hdl.handle.net/10044/1/28865 VL - 22 ER -