title: Multispectroscopic studies of the interaction of calf thymus DNA with the anti-viral drug, valacyclovir.
abstract: The present study investigated the binding interaction between an antiviral drug, valacyclovir and calf thymus DNA (CT-DNA) using emission, absorption, circular dichroism, viscosity and DNA melting studies. In fluorimetric studies, thermodynamic enhancement constant (K(D)) and bimolecular enhancement constant (K(B)) were calculated at different temperatures and demonstrated that fluorescence enhancement is not initiated by a dynamic process, but instead by a static process that involves complex DNA formation in the ground state. Further, the enthalpy and entropy of the reaction between the drug and CT-DNA showed that the reaction is exothermic and enthalpy-favored. In addition, detectable changes in the circular dichroism spectrum of CT-DNA in the presence of valacyclovir indicated conformational changes in the DNA double helix following interaction with the drug. All these results prove that this antiviral drug interacts with CT-DNA via an intercalative mode of binding.
authors.affiliation: Department of Chemistry, Faculty of Science, Razi University, Kermanshah, Iran. nahidshahabadi@yahoo.com
authors.forename: Nahid
authors.initials: N
authors.lastname: Shahabadi
authors.forename: Navid
authors.initials: N
authors.lastname: Fatahi
authors.forename: Maryam
authors.initials: M
authors.lastname: Mahdavi
authors.forename: Zahra Kiani
authors.initials: ZK
authors.lastname: Nejad
authors.forename: Mehdi
authors.initials: M
authors.lastname: Pourfoulad
mesh_terms: D000212:Acyclovir / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D000998:Antiviral Agents / Q000494:pharmacology*; D002417:Cattle; D002942:Circular Dichroism; D004247:DNA / Q000737:chemistry / Q000378:metabolism*; D009691:Nucleic Acid Denaturation; D013050:Spectrometry, Fluorescence; D013816:Thermodynamics; D000077483:Valacyclovir; D014633:Valine / Q000031:analogs & derivatives* / Q000494:pharmacology
chemical_list: D000998:Antiviral Agents; D004247:DNA; C427203:calf thymus DNA; D014633:Valine; D000077483:Valacyclovir; D000212:Acyclovir