【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 .这为分析DNA分子的结构特征提供了一种新方法更多还原

【Abstract】 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)=A2∫ L 0κ 2 d s and E T (r)=2π 2CL(ΔLk-Wr) 2.The energy decreases with increasing the chain length of DNA.We find that E B is greater than E T by 10～10 2 times.In the same time,the relationship between 〈R 2 g〉 and chain length n is 〈R 2 g 〉=1169 5-3 5×n+0 025×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.更多还原