DNA 弯曲蛋白相互作用范围受弯曲波动第二长相关长度控制。
Range of interaction between DNA-bending proteins is controlled by the second-longest correlation length for bending fluctuations.
机构信息
Department of Physics and Astronomy, Northwestern University, Evanston, Illinois 60208, USA.
出版信息
Phys Rev Lett. 2012 Dec 14;109(24):248301. doi: 10.1103/PhysRevLett.109.248301. Epub 2012 Dec 10.
When a DNA molecule is stretched, the zero-force correlation length for its bending fluctuations-the persistence length A-bifurcates into two different correlation lengths-the shorter "longitudinal" correlation length ξ_{∥}(f) and the longer "transverse" correlation length ξ_{⊥}(f). In the high-force limit, ξ_{∥}(f)=ξ_{⊥}(f)/2=sqrt[k_{B}TA/f]/2. When DNA-bending proteins bind to the DNA molecule, there is an effective interaction between the protein-generated bends mediated by DNA elasticity and bending fluctuations. Surprisingly, the range of this interaction is not the longest correlation length associated with transverse fluctuations of the tangent vector along the polymer, but instead is the second longest longitudinal correlation length ξ_{∥}(f,μ). The effect arises from the protein-bend contribution to the Hamiltonian having an axial rotational symmetry which eliminates its coupling to the transverse fluctuations.
当 DNA 分子被拉伸时，其弯曲波动的零力相关长度（持久长度）A 分叉成两个不同的相关长度 - 较短的“纵向”相关长度 ξ_{∥}(f) 和较长的“横向”相关长度 ξ_{⊥}(f)。在高力极限下，ξ_{∥}(f)=ξ_{⊥}(f)/2=sqrt[k_{B}TA/f]/2。当 DNA 弯曲蛋白结合到 DNA 分子上时，由 DNA 弹性和弯曲波动介导的蛋白产生的弯曲之间存在有效相互作用。令人惊讶的是，这种相互作用的范围不是与聚合物上切向量横向波动相关的最长相关长度，而是第二个最长的纵向相关长度 ξ_{∥}(f,μ)。这种效应源于蛋白质弯曲对哈密顿量的贡献具有轴向旋转对称性，从而消除了它与横向波动的耦合。
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