title: Spectroscopic and thermodynamic insights into the interaction between proflavine and human telomeric G-quadruplex DNA.
abstract: The G-quadruplex (GQ-DNA), an alternative structure motif of DNA, has emerged as a novel and exciting target for anticancer drug discovery. GQ-DNA formed in the presence of monovalent cations (Na(+)/K(+)) by human telomeric DNA is a point of interest due to their direct relevance for cellular aging and abnormal cell growths. Small molecules that selectively target and stabilize G-quadruplex structures are considered to be potential therapeutic anticancer agents. Herein, we probe G-quadruplex and proflavine (a well-known DNA intercalator, hence acting as an anticarcinogen) association through steady state and time-resolved fluorescence spectroscopy to explore the effect of stabilization of GQ-DNA by this well-known DNA intercalator. The structural modifications of G-quadruplex upon binding are highlighted through circular dichroism (CD) spectra. Moreover, a detailed insight into the thermodynamics of this interaction has been provided though isothermal titration calorimetry (ITC) studies. The thermodynamic parameters obtained from ITC help to gain knowledge about the nature as well as the driving forces of binding. This present study shows that proflavine (PF) can act as a stabilizer of telomeric GQ-DNA through an entropically as well as enthalpically feasible process with high binding affinity and thereby can be considered as a potential telomerase inhibitor.
authors.affiliation: Department of Chemistry, Indian Institute of Science Education and Research (IISER)-Pune , Pune 411008, Maharashtra India.
authors.forename: Vivek
authors.initials: V
authors.lastname: Kumar
authors.forename: Abhigyan
authors.initials: A
authors.lastname: Sengupta
authors.forename: Krishna
authors.initials: K
authors.lastname: Gavvala
authors.forename: Raj Kumar
authors.initials: RK
authors.lastname: Koninti
authors.forename: Partha
authors.initials: P
authors.lastname: Hazra
mesh_terms: D002151:Calorimetry; D004247:DNA / Q000737:chemistry*; D054856:G-Quadruplexes; D006801:Humans; D011370:Proflavine / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D013816:Thermodynamics
chemical_list: D004247:DNA; D011370:Proflavine