Qian H, White J H
Department of Applied Mathematics, University of Washington, Seattle 98195, USA.
J Biomol Struct Dyn. 1998 Dec;16(3):663-9. doi: 10.1080/07391102.1998.10508278.
It is well known that a large linking number induces an abrupt writhing of a circular rod with zero intrinsic curvature, i.e., the stress-free state of the rod is straight. We show here that for any rod with a uniform natural curvature, no matter how small the intrinsic curvature is, a twist will induce a continuous writhing from the circular configuration and the abrupt writhing is only the limiting case when the intrinsic curvature is absolutely zero. The implication of this result on elastic models of circular DNA is discussed.
众所周知，较大的环绕数会使具有零固有曲率的圆形杆突然发生扭曲，即杆的无应力状态是直的。我们在此表明，对于任何具有均匀自然曲率的杆，无论固有曲率有多小，扭转都会导致从圆形构型产生连续的扭曲，而突然扭曲只是固有曲率绝对为零时的极限情况。讨论了这一结果对环状DNA弹性模型的意义。
