石英壓電晶體感測器應用於無機化合物與DNA作用力的研究

The Interaction between Inorganic Compounds and Calf Thymus-DNA Studied by Quartz Crystal Microbalance

許嘉琪(Chia- Chi Hsu)

指導教授 ： 施正雄

國立臺灣師範大學/理學院/化學系/碩士(2000年)

摘要

無資料

關鍵字

石英壓電晶體 ； 去氧核糖核酸 ； 金屬離子 ； 作用力

並列摘要

ct-DNA was immobilized on the silver electrode surface of piezoelectric quartz crystal by the covalent binding to 3-carboxypropyl disulfide (CPS) in EDAC/NHS solution. The DNA attachment is attributed to the formation of amide bond between the carboxylate groups of CPS and the amino groups on the DNA bases. The binding site and the concentration effect on the interaction between 3-carboxypropyl disulfide and ct-DNA were investigated. Interaction between inorganic compounds and calf thymus-DNA was studied by piezoelectric quartz crystal detection system.
Alkali metal and NH4+ ions exhibited nonspecific physical binding with ct-DNA. Alkali-earth metal ions, e.q., Mg2+, Ca2+, Sr2+ and Ba2+ showed some chemical binding with ct-DNA and the chemical binding could be arranged in the order: Ca2+ > Ba2+ ~ Sr2+ > Mg2+. The chemical interaction of alkali-earth showed stronger than that of alkali metal ions, but weaker than that of transition metal ions. Transition metal ions showed relatively strong chemical binding with ct-DNA. The binding ability could be arranged in the order: Ag+ > Hg2+ > Cu2+ > Cr3+ ~ Ni2+ > Co2+ >Fe3+ ~ Mn2+ ~ Zn2+. The concentration effect and binding number per nucleotide for the interaction between transition metal ions and ct-DNA were also investigated by the system. Ag+, Hg2+ and Cu2+ binding to DNA could result in intramolecular as well as intermolecular crosslinking and thus have great binding number per nucleotide. These ions react with single or double strands DNA to form a stable metal-DNA complex.
The interaction of DNA with other inorganic species such as carbon monoxide, hydrogen peroxide, inorganic base and acid were also studied.
Hydrogen peroxide and inorganic base such as NaOH and NH3 would denature the double strand DNA, while inorganic acid and carbon monoxide showed relative small binding to DNA.
Interaction of metal ions, e.g., Cu2+ with different polynucleotides (polyG, polyC, polyA, and polyU) was also investigated by the QCM system. Cu2+ showed different affinities with the four kinds of bases, in the order: G > C > A > U. The binding number per nucleotide for Cu2+ was also calculated. The major binding sites could be N(7), O(6) of guanine, N(3), O(2) of cytosine, and N(7), O(6) of adenine.
Other factors such as (1) different kinds of DNA, (2) double and single strand DNA, (3) ionic strength, (4) pH value, (5) temperature effect on the frequency response for Cu2+ binding to DNA/CPS PZ crystal were also investigated. There is no significant difference for Cu2+ binding to ct-DNA, st-DNA and ht-DNA, which may be attributed to the similar molar percentages of the base pairs (A=T, GºC) in those DNA. Upon forming intramolecular or intermolecular crosslinking, ds-ctDNA has to deprotonate the hydrogen and break a hydrogen binding. Cu2+ binding to ss-ctDNA without beraking hydrogen bond have a greater binding number than ds-DNA. Ionic strength also has a great effect on the frequency response for Cu2+ binding to DNA/CPS immobilized PZ crystal. The existence of Na+ stabilized the double strand helix and resulted in less binding affinity of Cu2+ toward DNA in the presence of Na+ ions. The Cu2+ ion showed a greater binding amount to DNA at high pH than at low pH. At low temperature, the DNA double helix demonstrated low binding affinity to Cu2+. As the temperature was raised, the DNA started to denature and the binding amount for Cu2+ with ct-DNA increased. However, weaker binding of Cu2+ to DNA was observed at higher temperature.

並列關鍵字

QCM ； DNA ； metal ions ； interaction

參考文獻

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