Marck C, Guschlbauer W
Nucleic Acids Res. 1978 Jun;5(6):2013-31. doi: 10.1093/nar/5.6.2013.
A procedure for the computation of the first neighbour frequencies of DNA's is presented. This procedure is based on the first neighbour approximation of Gray and Tinoco. We show that the knowledge of all the ten elementary CD signals attached to the ten double stranded first neighbour configurations is not necessary. One can obtain the ten frequencies of an unknown DNA with the use of eight elementary CD signals corresponding to eight linearly independent polymer sequences. These signals can be extracted very simply from any eight or more CD spectra of double stranded DNA's of known frequencies. The ten frequencies of a DNA are obtained by least square fit of its CD spectrum with these elementary signals. One advantage of this procedure is that it does not necessitate linear programming, it can be used with CD data digitalized using a large number of wavelengths, thus permitting an accurate resolution of the CD spectra. Under favorable case, the ten frequencies of a DNA (not used as input data) can be determined with an average absolute error < 2%. We have also observed that certain satellite DNA's, those of Drosophila virilis and Callinectes sapidus have CD spectra compatible with those of DNA's of quasi random sequence; these satellite DNA's should adopt also the B-form in solution.
本文介绍了一种计算DNA一级邻位频率的方法。该方法基于格雷和蒂诺科的一级邻位近似。我们表明，了解与十种双链一级邻位构型相关的所有十种基本圆二色性（CD）信号并非必要。利用对应于八个线性独立聚合物序列的八个基本CD信号，就可以得到未知DNA的十种频率。这些信号可以非常简单地从已知频率的双链DNA的任意八个或更多CD光谱中提取。通过将DNA的CD光谱与这些基本信号进行最小二乘拟合，可得到DNA的十种频率。该方法的一个优点是不需要线性规划，它可以用于使用大量波长数字化的CD数据，从而实现CD光谱的精确解析。在有利情况下，DNA的十种频率（未用作输入数据）可以以平均绝对误差<2%来确定。我们还观察到，某些卫星DNA，即果蝇和美洲蓝蟹的卫星DNA，其CD光谱与准随机序列DNA的光谱兼容；这些卫星DNA在溶液中也应采用B型。
