Frank-Kamenetskii M D, Lukashin A V, Anshelevich V V, Vologodskii A V
Institute of Molecular Genetics, USSR Academy of Science, Moscow.
J Biomol Struct Dyn. 1985 Feb;2(5):1005-12. doi: 10.1080/07391102.1985.10507616.
We have calculated the variance of equilibrium distribution of a circular wormlike polymer chain over the writhing number, [Wr)2), as a function of the number of Kuhn statistical segments, n. For large n these data splice well with our earlier results obtained for a circular freely jointed polymer chain. Assuming that [delta Lk)2) = [delta Tw)2) we have compared our results with experimental data on the chain length dependence of the [delta Lk)2) value recently obtained by Horowitz and Wang for small DNA rings. This comparison has shown an excellent agreement between theory and experiment and yielded a reliable estimate of the torsional and bending rigidity parameters. Namely, the torsional rigidity constant is C = 3.0.10(-19) erg cm, and the bending rigidity as expressed in terms of the DNA persistence length is a = 500 A. The obtained value of C agrees well with earlier estimates by Shore and Baldwin as well as by Horowitz and Wang whereas the a value is in accord with the data of Hagerman. We have found the data of Shore and Baldwin on the chain length dependence of the [delta Lk)2) value to be entirely inconsistent with our theorectical results.
我们计算了环形蠕虫状聚合物链在缠绕数[Wr)²]上的平衡分布方差，它是库恩统计链段数n的函数。对于较大的n，这些数据与我们早期针对环形自由连接聚合物链得到的结果吻合得很好。假设[δLk)²] = [δTw)²]，我们将我们的结果与霍洛维茨和王最近获得的关于小DNA环的[δLk)²]值对链长依赖性的实验数据进行了比较。这种比较表明理论与实验之间具有极好的一致性，并得出了扭转刚度和弯曲刚度参数的可靠估计值。具体而言，扭转刚度常数C = 3.0×10⁻¹⁹尔格·厘米，以DNA持久长度表示的弯曲刚度a = 500埃。得到的C值与肖尔和鲍德温以及霍洛维茨和王早期的估计值吻合得很好，而a值与哈格曼的数据一致。我们发现肖尔和鲍德温关于[δLk)²]值对链长依赖性的数据与我们的理论结果完全不一致。
