Biomedical subjects

Tetsuo Kozasa

Publications and source records attributed to Tetsuo Kozasa.

5 recordsLinked to original sources

PubMed2006

Detection of C:C mismatch base pair by fluorescence spectral change upon addition of silver (I) cation: toward the efficient analyses of single nucleotide polymorphism.

We have already found that silver (I) cation specifically binds to C:C mismatch base pair in heteroduplex, which increases the melting temperature of heteroduplex involving C:C mismatch base pair by about 4 degrees C. This result shows that addition of the metal cation is a promising strategy for the mismatch base pair detection in heteroduplex, but UV melting to determine the melting temperature is time-consuming. In the present study, to develop a more convenient way for the mismatch base pair detection, we examined the fluorescence spectral change of fluorescent-labelled duplex upon addition of the metal cation. Addition of silver (I) cation to the heteroduplex involving the C:C mismatch base pair significantly changed the fluorescence intensity, but no significant change in the fluorescence intensity was observed for the duplexes involving other base pairs. Our results certainly support the idea that the fluorescence spectral change upon the addition of the metal cation could be a convenient strategy for the mismatch base pair detection by the heteroduplex analysis, and may eventually lead to progress in SNP genotyping.

Base Pair Mismatch↗

PubMed2006

Detection of T:T mismatch base pair by fluorescence spectral change upon addition of mercury (II) cation: toward the efficient analyses of single nucleotide polymorphism.

We have already found that mercury (II) cation specifically binds to T:T mismatch base pair in heteroduplex, which increases the melting temperature of heteroduplex involving T:T mismatch base pair by about 4 degrees C. This result shows that addition of the metal cation is a promising strategy for the mismatch base pair detection in heteroduplex, but UV melting to determine the melting temperature is time-consuming. In the present study, to develop a more convenient way for the mismatch base pair detection, we examined the fluorescence spectral change of fluorescent-labelled duplex upon addition of the metal cation. Addition of mercury (II) cation to the heteroduplex involving the T:T mismatch base pair significantly changed the fluorescence intensity, but no significant change in the fluorescence intensity was observed for the duplexes involving other base pairs. Our results certainly support the idea that the fluorescence spectral change upon the addition of the metal cation could be a convenient strategy for the mismatch base pair detection by the heteroduplex analysis, and may eventually lead to progress in SNP genotyping.

Base Pair Mismatch↗

PubMed2006

Thermodynamic analyses of the specific interaction between two C:C mismatch base pairs and silver (I) cations.

We have already found that a single silver (I) cation specifically binds to a single C:C mismatch base pair in heteroduplex, which increases the melting temperature (T(m)) of heteroduplex involving a single C:C mismatch base pair by about 4 degrees C. Here, to examine the properties of the interaction between two C:C mismatch base pairs and silver (I) cations, we analyzed the effect of silver (I) cations on the thermal stability of heteroduplexes involving two C:C mismatch base pairs. The positions of the two C:C mismatch base pairs in heteroduplex did not significantly affect the magnitude of the increase in T(m) upon addition of silver (I) cation, suggesting that the binding affinity of the first silver (I) cation with one of the two C:C mismatch base pairs and that of the second silver (I) cation with the other of the two mismatch base pairs may be independent of the positions of the two mismatch base pairs. The larger magnitude of the increase in T(m) for the second silver (I) cation binding than that observed for the first silver (I) cation binding suggests that the binding affinity for the second silver (I) cation may be significantly higher than that for the first silver (I) cation. Our results certainly support the idea that addition of the metal cation is a promising strategy for the mismatch base pair detection in the heteroduplex analysis and may eventually lead to progress in SNP genotyping.

Base Pair Mismatch↗

PubMed2005

Computational evaluation of the specific interaction between cation and mismatch base pair.

Ab initio calculations were carried out to characterize the structure and energetic of silver cation (Ag (I)) complex with cytosine (C:Ag:C) and mercury cation (Hg (II)) complex with thymine (T:Hg:T) systems. These metal-modified mismatch base pairs have been optimized using Hatree-Fock method without any symmetry constrains. Using above methods, the models of Ag (I) in a crosslink between O2 carbonyl oxygen of cytosine, O2(C):Ag:O2(C), and Hg (II) in a crosslink between N3 nitrogen atom of thymine, N3(T):Hg:N3(T) were obtained. Furthermore, the interaction energies of C:Ag:C and T:Hg:T models were estimated. The result showed that the coordination silver (I) cation with cytosine is more stable than hydrate state.

Base Pair Mismatch↗

PubMed2005

Thermodynamic analyses of the specific interaction between C:C mismatch base pair and silver (I) cation: toward the efficient detection of single nucleotide polymorphism.

We examined the effect of silver (I) cation on the thermal stability of heteroduplex and homoduplex. Addition of silver (I) cation increased the melting temperature of heteroduplex containing C:C mismatch base pair by about 4 degrees C. The thermal stability of homoduplex and heteroduplexes containing other kinds of mismatch base pairs was not significantly changed by the addition of silver (I) cation. Isothermal titration calorimetric study demonstrated that silver (I) cation directly bound to C:C mismatch base pair in heteroduplex at a molar ratio of 1:1. The binding constant and the enthalpy change for the binding of silver (I) cation to C:C mismatch base pair was approximately 10(6) M(-1) and -3 kcal mol(-1), respectively. We conclude that silver (I) cation directly binds to C:C mismatch base pair in heteroduplex with high affinity and specificity. Our results certainly support the idea that the addition of silver (I) cation to C:C mismatch base pair in heteroduplex could be a convenient strategy for heteroduplex analysis and may eventually lead to progress in single nucleotide polymorphism genotyping.

Base Pair Mismatch↗