Albany 2013: Book of Abstracts
June 11-15 2013
©Adenine Press (2012)
Electrochemical investigation of the interaction between G-quadruplex and some ligands using MWCNT modified carbon paste electrode
The G-quadruplex is an unusual DNA secondary structure, based on the Hoogesteen G–G base pairing, which stabilizes in the presence of certain metal cations, mainly alkali ions such as K+ (Elahi et al. 2012). In continuing with our previous studies on the interaction between DNA and small molecules (Heli et al. 2004; Ghanbari et al. 2008), more recently interaction of G-DNA with polyamines and ethidium bromide was studied (Elahi et al. 2012). In the present study we investigated the interaction of carotenoids (crocin and crocetin) and monoterpene aldehydes (safranal) of saffron with G-DNA. The MWCNT was ultrasonically treated in 35% solution of nitric acid for 6 h to be functionalized with carboxylic acid groups. The carbon paste electrode was prepared by mixing graphite powder with paraffin at the ratio 65:35. The resulting paste was packed into Teflon tube. The outer layer of the electrode was made of carbon paste modified by addition of the modified MWCNT at the concentration of 10% (w/w). G-DNA was covalently immobilized onto the CPE modified with MWCNT (MWCNT/CPE) in the presence of EDC/NHS. Interaction of G-DNA with he named ligands was investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) using the electroactive complex [Ru(NH3)6]3+ (RuHex). The results showed that, crocetin has more affinity than crocin and safranal for binding to G-DNA. Binding constants for these interactions are 4.4×104, 1.4×104, and 1.6 ×104 M-1 for crocetin, crocin and safranal, repectively.
H. Heli, S.Z. Bathaie, M.F. Mousavi, Electrochem. Commun., 6 (2004) 1114-1118.
K. Ghanbari, S.Z. Bathaie, M.F. Mousavi, Biosens. Bioelectron., 23 (2008) 1825-1831.
1Department of Chemistry