摘要

预熔体的中心标志着基因的开始和结束

作者(年代):亨利·M·索贝尔

预熔子是突现结构(即结构孤子)的例子，由于DNA结构中存在非线性激励而在DNA中自发出现。它们有两种类型:B-B(或A-A)预熔体形成于特定的DNA区域，以形成特定位置的DNA熔化。它们是静止的，并且全局非拓扑，经历呼吸运动，允许药物和染料嵌入DNA。另一方面，B- a(或A-B)预熔体是可移动的，并且具有全局拓扑，在结构相变过程中充当将B-转化为A-DNA的相边界。他们不需要进行呼吸运动。这两种类型的预熔体的一个关键特征是在它们的中心区域存在中间结构形式(被认为是dna熔化和B-到A-转变的过渡态中间体)，这与A-或B- dna不同。它被称为β - DNA，既是亚稳的，又是超柔韧的，并且含有沿着聚合物主干的交替糖皱模式，并结合其他碱基对的部分解叠(以其低能量形式)。β - dna通过具有非线性结构变化等级的边界与B- dna或a- dna连接，这些被称为扭结区和反扭结区。DNA中预熔体的存在导致了一个统一的理论，以理解DNA的物理化学和分子生物学。特别是，预熔体被预测为定义5?? and 3??? ends of genes in naked-DNA and DNA in active chromatin, this having important implications for understanding physical aspects of the initiation, elongation and termination of RNA-synthesis during transcription. For these and other reasons, the model will be of broader interest to the general audience working in these areas. The model explains a wide variety of data, and carries within it a number of experimental predictions all readily testable as will be described in the presentation. Recent Publications 1. Sobell H M (2016) Premeltons in DNA. Journal of Structural and Functional Genomics 17(1):17-31. 2. Sobell H M (2009) Premeltons in DNA. A Unifying Polymer Physics Concept to Understand DNA Physical Chemistry and Molecular-Biology. Explanatory Publications ISBN-978-0-615-33828-6. 3. Sobell H M (2013) Organization of DNA in Chromatin. Rather than bending uniformly along its length, nucleosomal DNA is proposed to consist of multiple segments of B- and A- DNA held together by kinks when forming its left-handed toroidal superhelical structure. Explanatory Publications ISBN-978-0-692-01974-0