Srinivasan R, Geetha V, Seetharaman J, Mohan S
Department of Crystallography and Biophysics, University of Madras, India.
J Biomol Struct Dyn. 1993 Dec;11(3):583-96. doi: 10.1080/07391102.1993.10508017.
A generalised method of characterising the three dimensional structure of any biopolymer is proposed. The method makes use of rotation and superposition of identical rigid monomeric units that comprise the polymer. Out of the various parameters involved (refers the seven parametric representation of relating two identical rigid bodies in space), the angle of rotation and superposition termed as 'phi s' turns out to be essentially unique. An ideal biopolymer with n identical rigid units is characterised by (n-1) such unique angles. In applying the results to real biopolymers, the importance of recognising that monomeric units are no more rigid but only quasi-rigid is emphasised. However, by appropriate choice of 'rigid' fraction of the quasi-rigid monomers, one is led, as first approximation, to essentially unique characterisation of the biopolymer with (n-1) such unique angles. The phi s as a function of residue number acts essentially as a finger print of the given polymeric fold and the conformation of the chosen biopolymer. However, the full set of seven parameters are needed for model building. It is emphasised that the method is general in its application to any polymer and the application of the results to proteins and nucleic acids is illustrated.
本文提出了一种描述任何生物聚合物三维结构的通用方法。该方法利用构成聚合物的相同刚性单体单元的旋转和平移。在涉及的各种参数中（指空间中两个相同刚体的七种参数表示），旋转和平移角度（称为“φs”）实际上是唯一的。具有n个相同刚性单元的理想生物聚合物由（n - 1）个这样的唯一角度表征。在将结果应用于实际生物聚合物时，强调了认识到单体单元不再是刚性的而是准刚性的重要性。然而，通过适当选择准刚性单体的“刚性”部分，作为一阶近似，可以用（n - 1）个这样的唯一角度对生物聚合物进行基本唯一的表征。作为残基数函数的φs基本上起到了给定聚合物折叠和所选生物聚合物构象的指纹作用。然而，模型构建需要完整的七个参数集。强调该方法在应用于任何聚合物时具有通用性，并举例说明了将结果应用于蛋白质和核酸的情况。
