SUPER HIGH DENSITY REVERSIBLE PHOTORECORDING SYSTEM SIMULATED BY DUPLEX OF DNA.

紫外光照射DNA会引起嘧啶碱基的光反应。溶液中的胸腺嘧啶化合物会产生四种光二聚体。而DNA中的胸腺嘧啶光二聚体只产生一种异构体，即顺式-顺式光二聚体。这是因为DNA中胸腺嘧啶碱基的取向是由碱基配对控制的。本项目的目的是模拟DNA中胸腺嘧啶的光二聚反应，以及在高密度可逆光记录系统中的应用。首先，研究了溶液中聚胸腺嘧啶（poly T）在聚腺苷酸（poly A）存在或不存在下的光二聚反应，发现聚腺苷酸（poly A）的存在提高了聚胸腺嘧啶（poly T）的光二聚反应活性。为了将胸腺嘧啶的光二聚反应应用于光记录系统，必须研究固态光反应，本文首先研究了胸腺嘧啶衍生物的固态光二聚反应 关于我们 从1-烷基胸腺嘧啶在单晶中的光二聚反应的结果来看，胸腺嘧啶的光二聚反应是通过晶体中的反旋运动进行的，除了晶体取向外，胸腺嘧啶碱基的旋转运动也是影响胸腺嘧啶固态光二聚反应的重要因素，在胸腺嘧啶的四种光二聚体中，在240 nm光照射下，顺式-顺式光二聚体很容易生成胸腺嘧啶，这一事实表明，胸腺嘧啶衍生物可以实现完全可逆的光二聚反应，只生成顺式-顺式光二聚体。两个胸腺嘧啶碱基通过两个丙基连接，环状双胸腺嘧啶化合物的光二聚反应只产生顺式-顺式光二聚体，光二聚反应是完全可逆的，这一结果可望用于高密度可逆光记录系统。少

Irradiation of UV light on DNA causes photoreactions of pyrimidine bases.Thymine compounds in solution gives four kinds of photodimer.Photodimerization of thymine in DNA, however, afford only one isomer, cis-syn photodimer.This reason is that orientation of thymine bases in DNA is controlled by base pairing with.The object of this project is a simulation of the photodimerzation of thymine in DNA, and application to high-density reversible photorecording system.At first, photodimerization reactions poly T were investigated in solution in the presence or absence of poly A.Increase of the reactivity of poly T for photodimerization was observed in the presence of poly A.The result indicated that controlled orientation of thymine caused an acceleration of the photodimerization reaction.In order to apply the photodimerization of thymine to the photorecording system, the photoreaction in solid state should be studied.Then, the photodimerization of the thymine derivatives was studied in solid … More film and single crystals.From the results of the photodimerization of 1-alkylthymine in single crystal, the photodimerization of thymine was found to be occurred by disrotatory motion in crystal.In addition to the orientation, mobility of thymine bases for rotation was found to be another important factor for the photodimerization of thymine in solid state.Among the four photodimers of thymine, cis-syn photodimer gives easily the original thymine by irradiation at 240 nm.This fact indicates that complete reversible photodimerization can be achieved by the thymine derivative which gives only cis-syn photodimer.Cyclic bis-thymine compounds were prepared and the photodimerization reaction was studied in this project.In this compound, two thymine bases are linked by two propyl groups.Photodimerization of the cyclic bis-thymine compound gave only cis-syn photodimer.Reversibility of the photodimerization was found to be complete.This result is to be expected for a high-density reversible photorecording system. Less