Lando D Y, Teif V B
Institute of Bioorganic Chemistry, Belarus National Academy of Sciences, Minsk.
J Biomol Struct Dyn. 2000 Apr;17(5):903-11. doi: 10.1080/07391102.2000.10506578.
Influence of long-range interactions between ligands bound to DNA molecule on the character of their adsorption is studied using computer modeling. For this investigation, two calculation procedures are developed. They are based upon the method of the free energy minimum and on the partition function method. The both procedures demonstrate that in the case of a strong enough attraction between all the bound ligands their binding to DNA has the character of phase transition of the first kind. There is a break in the binding curve c(c0) where c - relative concentration of bound ligands, c0 - molar concentration of free ligands. The break occurs because there is an interval of central degrees of binding (approximately 50% of the maximum c value) that are prohibited for individual DNA molecules. Such a transition might be caused by some types of DNA condensation. Attraction between the neighboring ligands only, adjacent or/and separated by double helix regions, does not cause this effect.
利用计算机建模研究了与DNA分子结合的配体之间的长程相互作用对其吸附特性的影响。为了进行这项研究，开发了两种计算程序。它们基于自由能最小化方法和配分函数方法。这两种程序都表明，在所有结合的配体之间存在足够强的吸引力的情况下，它们与DNA的结合具有一级相变的特征。结合曲线c(c0)存在一个断点，其中c是结合配体的相对浓度，c0是游离配体的摩尔浓度。出现断点是因为存在一个结合中心度的区间（约为最大c值的50%），单个DNA分子无法处于该区间。这种转变可能是由某些类型的DNA凝聚引起的。仅相邻配体之间的吸引力，无论相邻或/和被双螺旋区域隔开，都不会产生这种效应。
