Poly(dA).poly(dT) forms very stable nucleosomes at higher temperatures.
Poly(dA).poly(dT) forms very stable nucleosomes at higher temperatures.
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Poly(dA).poly(dT) 在较高温度下形成非常稳定的核小体。
DOI：
10.1006/jmbi.1994.0046
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发表时间：
1995
期刊：
影响因子：
--
通讯作者：
Behe,MJ
中科院分区：
文献类型：
--
作者：
Puhl,HL;Behe,MJ
合成的聚合物poly（dA）·poly（dT）长期以来被认为对核小体形成是难处理的。几年前，我们的实验室证明，聚合物核磁共振可以在低盐交换过程中与真正的核小体混合，形成一种核蛋白复合物，其行为方式与核小体相同。在37°C下的竞争性交换试验表明，同聚物重构的异质序列DNA大约与异质序列DNA一样。然而，其他实验室的研究表明，聚（dA）·聚（dT）的构象取决于温度;随着温度的升高，聚合物从其众所周知的非典型结构（在环境温度下发现）转化为更接近于标准B型的构象。我们测量了高嘌呤·高嘧啶形成核小体的能力作为温度的函数。可以看出，随着交换混合物温度的升高，poly（dA）·poly（dT）形成核小体的能力更强，因此poly（dA）·poly（dT）在升高的温度下与异质序列DNA竞争组蛋白。
The synthetic polymer poly(dA)·poly(dT) was long thought to be refractory to nucleosome formation. Several years ago our laboratory demonstrated that the polymr could be mixed with authentic nucleosomes in a low-salt exchange procedure to form a nucleoprotein complex that behaved in a manner identical with that of nucleosomes. Competitive exchange assays at 37°C showed that the homopolymer reconstituted about as well as heterogenous-sequence DNA. However, studies by other laboratories have shown that the conformation of poly(dA)·poly(dT) depends on temperature; the polymer converts from its well-known, atypical structure, found at ambient temperature, to a conformation more closely resembling a canonicalBform as temperature is increased. We have measured the ability of the homopurine·homopyrimidine to form nucleosomes as a function of temperature. It is seen that poly(dA)·poly(dT) forms nucleosomes more strongly as the temperature of the exchange mixture is increased, so that poly(dA)·(dT) outcompetes heterogeneous-sequence DNA for histones at elevated temperatures.