Probing the Strength and Mechanism of Binding Between Amifampridine and Calf Thymus DNA

Samira Sharifinia; Farshid Hajibabaei; Sadegh Salehzadeh; Neda Hosseinpour Moghadam; Sadegh Khazalpour

doi:10.1089/dna.2020.5618

Probing the Strength and Mechanism of Binding Between Amifampridine and Calf Thymus DNA

DNA Cell Biol. 2020 Oct 22. doi: 10.1089/dna.2020.5618. Online ahead of print.

Authors

Samira Sharifinia¹, Farshid Hajibabaei¹, Sadegh Salehzadeh¹, Neda Hosseinpour Moghadam², Sadegh Khazalpour¹

Affiliations

¹ Faculty of Chemistry, Bu-Ali Sina University, Hamedan, Iran.
² Research Center for Molecular Medicine, Hamadan University of Medical Sciences, Hamadan, Iran.

PMID: 33090906
DOI: 10.1089/dna.2020.5618

Abstract

In this work, we have investigated the strength and mechanism of amifampridine (3,4-Diaminopyridine/3,4-DAP) interaction with calf thymus DNA (ct-DNA). The existence and the strength of interaction are evaluated using circular dichroism (CD), UV-vis absorption, and differential pulse voltammogram studies. Results from UV-vis absorption technique indicate that amifampridine can significantly interact with DNA through a binding constant of K_b = 1.66 × 10⁵ M^-1 at 298 K. The mechanism of the interaction between amifampridine and DNA is also studied using ionic effect investigations, competitive fluorescence experiments, viscosity measurements, and molecular docking studies. The viscosity results indicate that amifampridine can bind to DNA via intercalation binding mode. Competitive fluorescence experiments using Acridine Orange (AO) and Hoechst 33258 (HO) probes also reveal that amifampridine binds to DNA via an intercalation mode of binding. Finally, the molecular docking studies also suggest that amifampridine tends to bind with the G-C rich region of DNA.

Keywords: CD; DNA interaction; DPV; amifampridine; intercalation; molecular docking.