弹性竿模型下超螺旋DNA分子的构象研究  

A STUDY ON CONFORMATIONS OF DNA CHAIN UNDER THE ELASTIC ROD MODEL

作　　者：姜舟婷[1] 章林溪[1] 陈进[1] 夏阿根[1] 叶高翔[1] 赵得禄[2] 

机构地区：[1]浙江大学物理系,杭州310028 [2]中国科学院化学研究所分子科学中心,北京100080

出　　处：《高分子学报》2003年第2期207-210,共4页Acta Polymerica Sinica

基　　金：国家自然科学基金 (基金号 2 98740 2 1;2 0 1740 3 6;2 0 2 740 40 );国家重点基础研究专项经费 (项目号 95 预 12和G19990 64 80 0 );浙江省自然科学基金 (基金号 10 10 0 2 )资助项目

摘　　要：采用弹性竿模型 (Elasticrodmodel) ,用MonteCarlo方法对DNA分子的构象进行研究 .通过计算发现 ,DNA分子的能量是由弯曲势能EB 和扭转势能ET 两部分组成 ,通常EB 比ET 大一至两个数量级 .同时给出了均方回转半径与链长之间的关系为〈R2g〉 =1 1 69 5 -3 5×n +0 0 2 5×n2 ,它体现了DNA分子结构的特点 .验证了公式Lk=Wr+Tw ,得出Lk与Wr比较接近的结论 ,考虑DNA分子的构型 ,意味着DNA分子容易被弯曲而不易被扭转 ,但随着连接系数的增加 ,DNA被扭转的几率也在增加 .The conformations of DNA chains are studied under the elastic rod model by Metropolis Monte Carlo simulation. The energy of DNA chains includes the bending energy E-B, and the twisting energy E-T, and they can be expressed in the form of E-B(r) = A/2 integral(0)(L) kappa(2)ds and E-T (r) = 2pi(2) C/L (DeltaLk - Wr)(2). The energy decreases with increasing the chain length of DNA. We find that E,, is greater than E, by 10 _ 102 times. In the same time, the relationship between <R-g(2)> and chain length n is <R-g(2)> = 1169.5 - 3.5 x n + 0.025 x n(2). The equation of Lk = Wr + Tw is verified, and the values of Lk and Wr are found to be very close to each other. It shows that DNA chain is easier to be bent than to be twisted. But for the large value of Lk, the tendency of torsion becomes large. Our simulation can provide a new method to analyze the conformations of DNA chains.

关 键 词：弹性竿模型 DNA分子 构象 超螺旋结构 生物分子 MONTECARLO模拟 分了链 

分 类 号：Q523[生物学—生物化学]