The specific interaction between two T:T mismatch base pairs and mercury (II) cation

Abstract

We have already found that a single mercury (II) cation specifically binds to a single T:T mismatch base pair in heteroduplex, which increases the melting temperature of heteroduplex involving a single T:T mismatch base pair by about 4 degrees C. Here, to examine the thermodynamic properties involving two T:T mismatch base pairs, we analyzed the interaction between mercury (II) cations and heteroduplex involving two T:T mismatch base pairs by isothermal titration calorimetry. The difference in the positions of the two T:T mismatch base pairs did not significantly affect the magnitudes of the stoichiometry and the thermodynamic parameters for the interaction between mercury (II) cations and the two T:T mismatch base pairs. Two mercury (II) cations bind with two T:T mismatch base pairs. The binding affinity for the second mercury (II) cation was significantly larger than that for the first mercury (II) cation. Our results certainly support the idea that addition of the mercury (II) cation is a promising strategy for the T:T mismatch base pair detection in the heteroduplex analysis and may eventually lead to progress in SNP genotyping.