Spontaneous sharp bending of double-stranded DNA
Spontaneous sharp bending of double-stranded DNA
复制标题
DOI：
10.1016/s1097-2765(04)00210-2
复制
发表时间：
2004-05-07
期刊：
影响因子：
16
通讯作者：
Widom, J
中科院分区：
文献类型：
--
作者：
Cloutier, TE;Widom, J
急剧弯曲的DNA是原核生物基因调控所必需的，也是真核生物核小体和病毒的主要特征。通常对这些现象的解释是，特定的蛋白质通过施加大的力而使DNA急剧弯曲，而DNA尽管具有内在的可折叠性，也会随之弯曲。在这里，我们发现，长度为94 bp的DNA--与体内的锐环DNA相当--自发地弯曲成环。蛋白质可以增强这种环的稳定性，但即使在裸DNA中，环也会自发地发生。随机DNA序列的环化比目前DNA弯曲理论预测的要容易10（2）-10（4）倍，而定位核小体的DNA序列的环化要容易105倍。这些意想不到的结果确立了DNA作为体内环状调节复合物形成的积极参与者，并且它们指出需要新的DNA弯曲理论。
Sharply bent DNA is essential for gene regulation in prokaryotes and is a major feature of eukaryotic nucleosomes and viruses. The explanation normally given for these phenomena is that specific proteins sharply bend DNA by application of large forces, while the DNA follows despite its intrinsic inflexibility. Here we show that DNAs that are 94 bp in length-comparable to sharply looped DNAs in vivo-spontaneously bend into circles. Proteins can enhance the stability of such loops, but the loops occur spontaneously even in naked DNA. Random DNA sequences cyclize 10(2)-10(4) times more easily than predicted from current theories of DNA bending, while DNA sequences that position nucleosomes cyclize Up to 105 times more easily. These unexpected results establish DNA as an active participant in the formation of looped regulatory complexes in vivo, and they point to a need for new theories of DNA bending.