嗜酸热硫球菌染色质碱性蛋白的提取

ISOLATION OF BASIC CHROMATIN PROTEINS OF ARCHAEBACTERIUM SULFOSPHAERELLUS THERMOACIDOPHILUM

组蛋白是典型真核细胞中普遍存在的染色质碱性蛋白.早已有证据表明它们是一组高度保守的蛋白,其中四种核心组蛋白有着共同的起源,来自于同一始祖性的蛋白(组蛋白H1则有另外的起源).这种始祖性的蛋白如何进化发展成现今的组蛋白,人们最易想到的是从原核生物中去寻找线索.然而,迄今在原核生物的真细菌类(eubacteria)中所发现的染色质碱性蛋白无一与组蛋白有显著的同源性.70年代末以来,原核生物的另一类群——古细菌(Archaebacteria)类的陆续发现为这个问题的探明带来了希望.因为一系列的分子生物学证据表明,在亲缘关系上,古细菌类远比真细菌类更接近真核生物.目前在我国已发现几种古细菌,嗜酸热硫球菌(Sulfosphaerellus thermoacidophilum)即是其中之一.本工作利用我们建立的先用甲醇固定、后用稀盐酸抽提的方法对此古细菌的染色质碱性蛋白进行了提取,并将它与小牛胸腺组蛋白进行了比较研究.

By a simple, efficient procedure which is termed 'Methanol profix——Acid extraction', basic chromatin protein was isolated from an archaebacterium Su-lfosphaerellus thermoacidophilum successfully. Both SDS-PAGE and AUT-PAGEcomparison of the protein with histone isolated by the same procedure from calfthymus showed that it contained three major fractions. Like basic chromatin proteins of other archaebacteria reported previously, the molecular weights of the threefractions, which are about 7 200, 8 500 and 9 800 respectively, are all less than thatof calf thymus H4(MW 11 282). And they can be stained by Azocarmin G solution(pH7), which specially stains basic proteins such as histone.