Title
Lighting Up the Thioflavin T by Parallel-Stranded TG(GA)n DNA Homoduplexes
Author
Jinbo Zhu, Zhiqiang Yan, Weijun Zhou, Chuanbo Liu, Jin Wang, Erkang Wang
Year
2018
Journal
ACS Sensors
Abstract
Thioflavin T (ThT) was once regarded to be a specific fluorescent probe for the human telomeric G-quadruplex, but more other kinds of DNA were found that can also bind to ThT in recent years. Herein, we focus on G-rich parallel-stranded DNA and utilize fluorescence, absorbance, circular dichroism, and surface plasmon resonance spectroscopy to investigate its interaction with ThT. Pyrene label and molecular modeling are applied to unveil the binding mechanism. We find a new class of non-G-quadruplex G-rich parallel-stranded (ps) DNA with the sequence of TG(GA)n can bind to ThT and increase the fluorescence with an enhancement ability superior to G-quadruplex. The optimal binding specificity for ThT is conferred by two parts. The first part is composed of two bases TG at the 5′ end, which is a critical domain and plays an important role in the formation of the binding site for ThT. The second part is the rest alternative d(GA) bases, which forms the pshomoduplex and cooperates with the TG bases at the 5′ end to bind the ThT.
Instrument
J-820
Keywords
Circular dichroism, Induced circular dichroism, Ligand binding, DNA structure, Thermal stability, Biochemistry, Sensors, Materials