Burckhardt G, von Mickwitz C U, Zimmer C
Biomed Biochim Acta. 1983;42(7-8):867-83.
The binding of histone H1 with DNA and synthetic DNA duplex polymers with respect to its property to induce higher ordered structures has been studied using the DNA binding antibiotic netropsin as a probe. It was shown that the formation of distinct steps of different condensed structures (double-fibers, cable- and stem-like forms) is influenced by the ionic strength. CD titration data of DNA-H1 complexes with netropsin at 20 mM NaCl indicated no change in the binding to strong affinity sites (dA X dT clusters) as compared to free DNA's, while weak netropsin binding regions are strongly affected by competition interaction with H1. At low histone concentration the presence of netropsin favours the formation of double fibers. CD and electron microscopic findings indicated that at 20 mM NaCl the occurrence of condensed structures of DNA histone H1 complexes is not dependent on the base content. The major groove interaction of H1 most probably plays the major role in the formation of higher ordered structures. However, the minor groove binding might be involved as a secondary event. A hierarchy of relevant morphological structures observed for DNA-H1 complexes is presented.
利用DNA结合抗生素纺锤菌素作为探针，研究了组蛋白H1与DNA及合成DNA双链聚合物结合时诱导更高有序结构的特性。结果表明，不同凝聚结构（双纤维、索状和茎状形式）不同步骤的形成受离子强度影响。在20 mM NaCl条件下，DNA-H1复合物与纺锤菌素的CD滴定数据表明，与游离DNA相比，与强亲和力位点（dA×dT簇）的结合没有变化，而弱纺锤菌素结合区域受到与H1竞争相互作用的强烈影响。在低组蛋白浓度下，纺锤菌素的存在有利于双纤维的形成。CD和电子显微镜研究结果表明，在20 mM NaCl条件下，DNA组蛋白H1复合物凝聚结构的出现不依赖于碱基含量。H1与大沟的相互作用很可能在更高有序结构的形成中起主要作用。然而，小沟结合可能作为次要事件参与其中。本文展示了观察到的DNA-H1复合物相关形态结构的层次关系。
