Interactions of l-Arg with calf thymus DNA using neutral red dye as a fluorescence probe

The interaction between l-Arg and calf thymus DNA (ctDNA) in sodium acetate–acetic acid buffer (pH = 4) was investigated with the use of neutral red (NR) dye as a spectral probe coupled with UV–vis absorption, fluorescence, and circular dichroism (CD) spectroscopy technique. The UV absorption spectroscopy indicated that l-Arg interacted with ctDNA via electrostatic force and the fluorescence enhancing of the DNA–NR system verified the electrostatic interaction. In addition, detectable changes in the CD spectrum of ctDNA in the presence of l-Arg indicated conformational changes in the DNA double helix after interaction with the drug. Docking studies were found to corroborate the experimental results. All these results prove that this drug interacts with ctDNA via an electrostatic binding mode.

l-Arg binds with backbone phosphate groups of the double helix by electrostatic interaction, and it resulted in the conformational and micro-environmental changes of DNA.Figure optionsDownload as PowerPoint slideHighlights
► We investigated the interactions of l-Arg with DNA in molecular level.
► The experiments show conformation and activity of ctDNA has been affected by l-Arg.
► Potential links in DNA’s changes of structure and function were found by docking.