Van Holde K E, Allen J R, Tatchell K, Weischet W O, Lohr D
Biophys J. 1980 Oct;32(1):271-82. doi: 10.1016/S0006-3495(80)84956-3.
We have utilized micrococcal nuclease digestion and thermal denaturation studies to investigate the binding of DNA to the histone core of the nucleosome. We conclude that a total of approximately 168 base pairs (bp) of DNA can interact with the histone core under appropriate solution conditions, even in the absence of lysine-rich histones. The interactions in this total length of DNA can be divided into three classes: (a) approximately 22 bp at the ends is bound only at moderate ionic strength. It is easily displaced, and its removal yields the 146 bp core particle. (b) approximately 46 bp near the ends of the core DNA are quite weakly bound to the core, and are displaced at quite moderate temperatures. (c) The remaining central 100 bp are strongly bound, and interact with all of the sites on the histones which strongly protect DNA against DNAse I digestion. A theoretical analysis of the cleavage of nucleosomal DNA by DNAse I has been used to develop evidence that the pattern of protection offered by the histone core is very similar in nuclei to that in isolated core particles.
我们利用微球菌核酸酶消化和热变性研究来探究DNA与核小体组蛋白核心的结合情况。我们得出结论,即使在没有富含赖氨酸组蛋白的情况下,在适当的溶液条件下,总共约168个碱基对(bp)的DNA能够与组蛋白核心相互作用。这段DNA全长中的相互作用可分为三类:(a)两端约22 bp仅在中等离子强度下结合。它很容易被取代,去除它会产生146 bp的核心颗粒。(b)核心DNA末端附近约46 bp与核心的结合非常弱,在相当适中的温度下会被取代。(c)其余中间的100 bp结合紧密,并与组蛋白上所有能强烈保护DNA免受DNA酶I消化的位点相互作用。对DNA酶I切割核小体DNA的理论分析已被用于提供证据,表明组蛋白核心提供的保护模式在细胞核中与在分离的核心颗粒中非常相似。