Aviles F J, Diez-Cabellero T, Palau J, Albert A
Biochimie. 1978 Sep 4;60(5):445-51. doi: 10.1016/s0300-9084(78)80858-x.
The interactions in buffered 0.14 M NaCl (pH 7.0) of DNA, native or sonicated, with histone Hl and with its fragments N-Hl (residues 1-72) and C-Hl (residues 73-COOH), have been studied by using the techniques of sedimentation, thermal denaturation and solubility. Histone Hl shows a preferential affinity for high molecular weight DNA in comparison with sonicated DNA. The binding of histone Hl to sonicated DNA in 0.14 M NaCl is reversible and the reversibility decreases with time. These findings are consistent with the view that Hl is cooperatively distributed along DNA molecules and that this distribution is energetically more favoured for long DNA than for sonicated DNA. It has been found that under conditions of moderate salt concentration, the C-terminal region is the main one responsible for the interaction of Hl with DNA, and also for a cooperative distribution of the histone along the DNA molecules. Addition of urea to the solution produces a decrease of solubility of Hl-DNA complexes. This effect reflects an additional condensation of the complex, which is probably related to the unfolding of the globular part of the histone. It is suggested that this globular region does not play a substantial role in the condensation of Hl-DNA complexes. A model which takes into account the presence of free lysyl and phosphate groups within the complex is discussed.
利用沉降、热变性和溶解度技术，研究了天然或经超声处理的DNA在pH 7.0的0.14 M NaCl缓冲液中与组蛋白H1及其片段N - H1（第1 - 72位氨基酸残基）和C - H1（第73位氨基酸残基至羧基末端）的相互作用。与经超声处理的DNA相比，组蛋白H1对高分子量DNA表现出优先亲和力。在0.14 M NaCl中，组蛋白H1与经超声处理的DNA的结合是可逆的，且可逆性随时间降低。这些发现与以下观点一致：H1沿DNA分子协同分布，并且这种分布在能量上对长DNA比特超声处理的DNA更有利。已发现，在中等盐浓度条件下，C末端区域是负责H1与DNA相互作用以及组蛋白沿DNA分子协同分布的主要区域。向溶液中添加尿素会降低H1 - DNA复合物的溶解度。这种效应反映了复合物的额外凝聚，这可能与组蛋白球状部分的展开有关。有人认为，该球状区域在H1 - DNA复合物的凝聚中不起实质性作用。文中讨论了一个考虑复合物中游离赖氨酸基团和磷酸基团存在的模型。
