Theory of interaction between helical molecules
Theory of interaction between helical molecules
复制标题
DOI：
10.1063/1.475320
复制
发表时间：
1997-09-01
影响因子：
4.4
通讯作者：
Leikin, S
中科院分区：
文献类型：
--
作者：
Kornyshev, AA;Leikin, S
这项工作通过明确地将螺旋结构和对称性纳入理论，为理解各种类型螺旋分子之间的静电和溶剂化力奠定了基础。我们推导了具有圆柱形内核的分子之间相互作用的精确表达式和离散表面电荷的任意分布，并分析了单链、双链和多链螺旋之间的力。例如，我们证明，当单链螺旋上不到三分之一的链电荷被反电荷（由其性质吸附或固有于螺旋）中和时，传统的均匀带电棒近似就不合适了。传统上预期的力然后由螺旋特定的相互作用补充。这些螺旋特定力允许相应的螺旋（螺距比等于有理数）在一定距离内相互识别并自组装成集合体。在某些条件下，这些力可能导致自发的对称性丧失，例如，当分子靠近临界轴间分离时，两个dna型双螺旋围绕其长轴旋转到分离依赖的角度。一般来说，当较长范围的螺旋特异性吸引诱导自组装时，较短范围的螺旋特异性排斥阻止紧密的分子接触，从而产生力平衡，负责平衡中的非零表面分离。引力和斥力的衰减速率和振幅取决于螺旋螺距以及螺旋链的数量和相对位置。这些力的理论使我们能够解释生物螺旋（包括DNA、胶原蛋白和四链鸟苷大分子）之间相互作用的一些令人困惑的特征。(C) 1997年美国物理研究所。
This work builds a basis for understanding electrostatic and solvation forces between various types of helical molecules by explicitly incorporating the helical structure and symmetries into the theory. We derive exact expressions for interaction between molecules with cylindrical inner cores and arbitrary distribution of discrete surface charges and analyze forces between single-stranded, double-stranded, and multistranded helices. For example, we demonstrate that the traditional approximation by a homogeneously charged rod becomes inappropriate when even less than a third of the strand charge on a single-stranded helix is neutralized by countercharges (adsorbed or intrinsic to the helix by their nature). The traditionally expected force is then complemented by helix-specific interactions. These helix-specific forces allow commensurate helices (with the ratio of pitches equal to a rational number) to recognize each other at a distance and self-assemble into an aggregate. Under certain conditions, these forces may induce a spontaneous symmetry loss, e.g., two DNA-type double helices rotate around their long axes to a separation-dependent angle when the molecules come closer than a critical interaxial separation. In general, while a longer-range helix-specific attraction induces the self-assembly, a shorter-range helix-specific repulsion prevents the tight molecular contact creating a force balance responsible for a nonzero surface separation in equilibrium. The decay rates and the amplitudes of the attraction and of the repulsion depend on the helical pitch and on the number and relative disposition of the helical strands. The theory of these forces allows us to explain a number of puzzling features of interactions measured between biological helices, including DNA, collagen, and four-stranded guanosine macromolecules. (C) 1997 American Institute of Physics.