A Reduction-Triggered Fluorescence Probe for Sensing Nucleic Acids

Abstract

We have developed a reduction-triggered fluorescence probe with a new fluorogenic compound derivatized from Rhodamine for sensing oligonucleotides. The chemistry to activate the compound involves the reaction between the azide group of rhodamine derivatives and the reducing reagents, with the fluorescence signal appearing after reduction of the azide group. The signal/background ratio of this fluorogenic compound reached 2100-fold enhancement in fluorescence intensity. Dithio-1,4-threitol or triphenylphosphine as reducing reagents were successfully utilized for this chemistry to be introduced into the DNA probe. The genetic detection requires that two strands of DNA bind onto target oligonucleotides, one probe carrying a reducible fluorogenic compound while the other carries the reducing reagents. The reaction proceeds automatically without any enzymes or reagents under biological conditions to produce a fluorescence signal within 10-20 min in the presence of target DNA or RNA. In addition, the probe was very stable under biological conditions, even such extreme conditions as pH 5 solution, pH 10 solution, or high temperature (90 degrees C) with no undesirable background signal. The probes were successfully applied to the detection of oligonucleotides at the single nucleotide level in solution and endogenous RNA in bacterial cells.

Recent Advances in the Synthesis of Triarylmethanes by Transition Metal Catalysis

“…26 LiN(SiMe 3 ) 2 was found to be an effective base because it can generate benzyllithium intermediates by deprotonation of benzylic protons activated by η 6 -coordination of the arene to Cr(CO) 3 . After Pd-catalyzed coupling of this deprotonated species, the resulting triarylmethane−Cr(CO) 3 complex was decomposed by exposure to air and light to give the triarylmethane in excellent yield.…”

7‐Azidomethoxy‐Coumarins as Profluorophores for Templated Nucleic Acid Detection

“…The known examples include 7-azidocoumarin [11] and azide-substituted rhodamines. [12] However, certain drawbacks limit the scope of either caging strategy. The TPP-derivative of fluorescein is prone to phosphine oxidation and to hydrolysis of the phenolic ester, which hinders the application of this probe in cells.…”

Nucleic Acid-programmed Assemblies: Translating Instruction into Function in Chemical Biology

“…We first applied this strategy to coumarin (azidocoumarin [76] ) and then rhodamine (azidorhodamine, [77] bisazidorhodamine [78] ). In parallel, this strategy has been used by other research groups and applied to azidomethyl-fluorescein, [79] azidorhodamine, [80] bis-azidomethyl-fluorescein, [81] and bis-azidonaphtho-rhodamine. [82] The templated unquenching of the profluorophore through azide reduction generally proceeds quickly.…”