Herrmann A L, Cadilla C L, Cacheiro L H, Carne A F, Olins D E
Eur J Cell Biol. 1987 Feb;43(1):155-62.
An H1-like protein has been purified from the macronucleus (MAC) of the hypotrichous ciliated protozoan, Euplotes eurystomus. It is present in amounts comparable to the inner histones and is extracted by treatment with 5% perchloric acid or 0.65 M NaCl, but not by 0.35 M NaCl. Treatment of soluble MAC chromatin with the ionic exchange resin AG 50W-X2 in 80 mM NaCl removes MAC H1 and yields H1-depleted chromatin. Mac H1 is lysine-rich and deficient in acidic amino acids. The stoichiometry of the H1 protein is reduced in mononucleosome preparations, consistent with its postulated interaction with linker DNA regions. Thermal denaturation and circular dichroism studies reveal that H1-depleted chromatin contains a larger portion of destabilized DNA than control chromatin. The molecular weight of Euplotes MAC H1 is significantly smaller than most reported H1 proteins. Comparisons are made with extracts of macronuclei from other hypotrichous ciliated protozoa and published reports of other lower eukaryotes.
从多核纤毛虫类的阔口游仆虫的大核（MAC）中纯化出了一种类H1蛋白。其含量与核心组蛋白相当，可通过用5%的高氯酸或0.65M氯化钠处理来提取，但不能用0.35M氯化钠提取。在80mM氯化钠中用离子交换树脂AG 50W-X2处理可溶性MAC染色质可去除MAC H1并产生H1缺失的染色质。大核H1富含赖氨酸且酸性氨基酸含量低。在单核小体制剂中H1蛋白的化学计量比降低，这与其假定的与连接DNA区域的相互作用一致。热变性和圆二色性研究表明，与对照染色质相比，H1缺失的染色质含有更大比例的不稳定DNA。阔口游仆虫大核H1的分子量明显小于大多数已报道的H1蛋白。并与其他多核纤毛虫类的大核提取物以及其他低等真核生物的已发表报告进行了比较。
