Correlation between physical stability map and genetic map of DNA double strand

本项目的目的是揭示DNA分子线的物理稳定图谱与遗传图谱之间的相关性。作为物理稳定性图，我们研究了B-A相变和螺旋-线圈相变的物理稳定性。利用配备计算机控制的微子弹的多维分光光度计研究了高浓度乙醇引起的ColE1DNA的B-A相变。这种转变比长度较短的替代共聚物要宽，并且因限制片段的不同而不同。这些事实首次证明了B-A转变中的稳定性是沿着DNA长双链变化的。将双螺旋稳定性分布与大量DNA中基因的位置进行比较，揭示了“基因同源稳定倾向”：即每个蛋白质编码区在其特征值周围具有统一的稳定性分布的趋势。这种倾向是通过同义密码子的使用来实现的。摆动第三碱基处的冗余被用来抵消由于密码子的第一和第二碱基引起的局部G+C含量变化。

The purpose of this project is to reveal the correlation between physical stability map and genetic map of the DNA molecular thread. As the physical stability map, we have studied those in the B-A transition and the helix-coil transition.The B-A transition of ColE1 DNA caused by high ethanol concentrations has been studied by the multi-dimensional spectrophotometer equipped with the computer-controlled microbullet. The transition is broader than that of alternative copolymers with shorter lengths and varies among restriction fragments. These facts have provided the first evidence to prove that the stability in the B-A transition varies along a long DNA double strand.Comparison between the double-helix stability distribution and the location of genes in a large number of DNAs has disclosed the "gene homostabilizing propensity": the tendency for each protein coding region to have a uniform stability distribution around its own characteristic value. The propensity was found to be attained by the synonymous codon usage. The redundancy at the wobble third base is utilized to counterbalance the local G+C content variation due to the first and second bases of codons.