title: Development of a novel method to determine the concentration of heavy metal cations: application of the specific interaction between heavy metal cation and mismatch DNA base pair.
abstract: We have already found that Hg(II) cation specifically binds to T:T mismatch base pair in heteroduplex DNA, which increases the melting temperature of heteroduplex DNA involving T:T mismatch base pair by about 4 degrees C. We have also found that Ag(I) cation specifically binds to C:C mismatch base pair in heteroduplex DNA, which increases the melting temperature of heteroduplex DNA involving C:C mismatch base pair by about 4 degrees C. Using the specific interaction, we developed a novel sensor to determine the concentration of each of Hg(II) and Ag(I) cation. The sensor is composed of a dye-labelled T-rich or C-rich DNA oligonucleotide, F2T6W2D: 5'-Fam-T(2)CT(2)CT(2)C(4)T(2)GT(2)GT(2)-Dabcyl-3' or F2C6W2D: 5'-Fam-C(2)TC(2)TC(2)T(4)C(2)AC(2)AC(2)-Dabcyl-3', where 6-carboxyfluorescein (Fam) is a fluorophore and Dabcyl is a quencher. The addition of Hg(II) cation decreased the intensity of Fam emission of F2T6W2D at 520 nm in a concentration-dependent manner. Also, the addition of Ag(I) cation decreased the intensity of Fam emission of F2C6W2D at 520 nm in a concentration-dependent manner. We conclude that, using the novel sensor developed in this study, the concentration of each of Hg(II) and Ag(I) cation can be determined from the intensity of Fam emission at 520 nm.
authors.affiliation: Department of Applied Chemistry, Faculty of Science, Tokyo University of Science, Tokyo 162-8601, Japan.
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Kozasa
authors.forename: Yukako
authors.initials: Y
authors.lastname: Miyakawa
authors.forename: Miyako
authors.initials: M
authors.lastname: Fukushi
authors.forename: Akira
authors.initials: A
authors.lastname: Ono
authors.forename: Hidetaka
authors.initials: H
authors.lastname: Torigoe
mesh_terms: D020137:Base Pair Mismatch; D015374:Biosensing Techniques; D002412:Cations / Q000737:chemistry; D031541:Fluorescence Resonance Energy Transfer; D008628:Mercury / Q000032:analysis* / Q000737:chemistry; D012834:Silver / Q000032:analysis* / Q000737:chemistry
chemical_list: D002412:Cations; D012834:Silver; D008628:Mercury