作　　者： ; ;

机构地区： 华南师范大学

出　　处： 《光谱学与光谱分析》 2000年第3期280-282,共3页

摘　　要： 我们成功地获得了溶液中 poly(d A)·poly(d T)的喇曼光谱 ,并利用晶格动力学方法对于异规模型进行了简正分析。根据势能分布矩阵 (PED)对每一个模式进行了指定。结果表明异规模型的简振频率和 poly(d A)·poly(d T)的喇曼光谱符合得相当好 ,这说明溶液中的 poly(d A)· poly(d T)完全有可能保留了固体纤维中的异规模型结构。 Poly(dA)·poly(dT) is a kind of DNA which one st rand contains adenine(A) bases,and the other only thymine(T) bases.This DNA poss esses flexible structure and the X-ray diffraction for poly(dA)·poly(dT) fiber gives three different structures.So it is of interest to study poly(dA)·poly(d T) structure in solution.In this paper,Raman spectrum of poly(dA)·poly(dT) in 0.2 mol·L- -1 NaCl solution was recorded over the spectral range 750—1 000 cm- -1.The Raman bands at 817 cm- -1 and 843 cm- -1 exist simultaneously.This implied that the secondary structure of poly(dA)·poly(dT) i s neither A-conformation nor B-conformation.Normal mode analysis of heteronomo us secondary structure from poly(dA)·poly(dT) fibers was carried out by the lat tice dynamics.Normal modes were assigned by potential energy distribution (PED). The calculated frequencies are good agreement with the observed Raman spectrum.T his indicated that poly(dA)·poly(dT) in solution probably has the same structur e as poly(dA)·poly(dT) fiber,namely the poly(dA) chain has the C-3′-endo rin g pucker while the poly(dT) chain has the C-2′-endo ring pucker.

关 键 词： 喇曼光谱 晶格动力学

领　　域： [生物学] [生物学]