鸡肝染色质中紧密结合的非组蛋白染色体蛋白的DNA结合活性。
DNA-binding activity of tightly-bound nonhistone chromosomal proteins in chicken liver chromatin.
作者信息
Gates D M, Bekhor I
出版信息
Nucleic Acids Res. 1979 Jul 25;6(10):3411-26. doi: 10.1093/nar/6.10.3411.
We have isolated a nonhistone chromosomal protein fraction from chicken liver chromatin which possesses high affinity and preferential sequence DNA binding. Residually DNA-bound nonhistone chromosomal proteins after 2.0 M NaCl extraction of bulk chromatin are isolated. Bound proteins are released by dissociation of the complexes in 5.0 M urea/3.0 M NaCl. We have investigated the in vitro DNA-binding properties of this class. In contrast to other DNA-binding NHCP whose activities have been studied, direct DNA-binding activity is observed which is not abolished under conditions of high ionic strength (to 3.0 M NaCl). Strong preference in binding fractionated homologous DNA is observed, while binding of heterologous (E. Coli) DNA is negligible. The fractionation of homologous DNA permits the isolation of DNA for which this protein class displays strong binding preference, presumably through a concentration of binding sites. The composite data suggest sequence-specific interaction between this protein class and DNA, which is not abolished by high ionic strength.
我们从鸡肝染色质中分离出一种非组蛋白染色体蛋白组分，它具有高亲和力和对序列DNA的优先结合能力。在对大量染色质进行2.0M NaCl提取后，分离出残留与DNA结合的非组蛋白染色体蛋白。通过在5.0M尿素/3.0M NaCl中解离复合物来释放结合蛋白。我们研究了这类蛋白的体外DNA结合特性。与其他已研究过活性的DNA结合非组蛋白染色体蛋白不同，观察到直接的DNA结合活性，在高离子强度（至3.0M NaCl）条件下该活性不会被消除。观察到对分级分离的同源DNA有强烈的结合偏好，而异源（大肠杆菌）DNA的结合可忽略不计。同源DNA的分级分离允许分离出该蛋白类表现出强烈结合偏好的DNA，推测是通过结合位点的集中。综合数据表明该蛋白类与DNA之间存在序列特异性相互作用，且这种相互作用不会被高离子强度消除。
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