Reinert K E, Thrum H, Sarfert E
Nucleic Acids Res. 1980 Nov 25;8(22):5519-31. doi: 10.1093/nar/8.22.5519.
The interaction of the oligopeptide antibiotic netropsin (Nt) with (A . T) regions of DNA is characterized by a spectrum of discrete modes. This has been revealed by viscometric analysis, at 20 degrees C and 0.2 M "counterions", for NaDNA in a preceding and for NH4DNA in this paper. The increase of DNA contour length as induced by one Nt molecule was found to depend on the special mode only, while the respective stiffening is generally higher for NH4DNA. The latter property is interpreted in terms of an enhanced flexibility, relative to that of NaDNA, of the (A . T) cluster segments before complex formation. For some of the interaction modes of the DNA-Nt systems a difference in the number of corresponding binding sites has been observed. This phenomenon is understood by assuming an influence of the counterion species upon existing equilibria between different forms of the (A . T) cluster secondary structure. Not less than 5 to 10% of the total DNA are effected in this manner. Upper limits for the local differences in the axial rise per base pair are 0.04 nm and 0.02 nm.
寡肽抗生素纺锤菌素(Nt)与DNA的(A·T)区域之间的相互作用具有一系列离散模式的特征。这已通过粘度分析揭示,在20℃和0.2M“抗衡离子”条件下,前文针对NaDNA以及本文针对NH4DNA进行了研究。发现由一个Nt分子诱导的DNA轮廓长度增加仅取决于特定模式,而对于NH4DNA,相应的刚性通常更高。相对于NaDNA,这种特性可根据(A·T)簇段在形成复合物之前增强的柔韧性来解释。对于DNA-Nt系统的某些相互作用模式,已观察到相应结合位点数量的差异。通过假设抗衡离子种类对(A·T)簇二级结构不同形式之间现有平衡的影响来理解这一现象。以这种方式影响的DNA总量不少于5%至10%。每个碱基对轴向上升的局部差异上限为0.04nm和0.02nm。