Spiral structure of Escherichia coli HUαβ provides foundation for DNA supercoiling
Spiral structure of Escherichia coli HUαβ provides foundation for DNA supercoiling
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DOI：
10.1073/pnas.0611686104
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发表时间：
2007-03-13
影响因子：
11.1
通讯作者：
Adhya, Sankar
中科院分区：
文献类型：
--
作者：
Guo, Fusheng;Adhya, Sankar
我们确定的晶体结构的大肠杆菌的核苷酸相关的HU α β蛋白的X-射线衍射，并观察到异二聚体形成多聚体与八聚体单位在三个潜在的安排，这可能是专门的作用，在不同的DNA交易反应。特别重要的是，其中一种结构形成了具有左手旋转的螺旋细丝。负超螺旋DNA可以被建模为包裹在这个左手HU α β多聚体周围。而野生型HU在体外产生负DNA超螺旋，一个工程异源二聚体与改变的氨基酸残基的晶体中的左手螺旋蛋白的形成是有缺陷的过程中，从而提供了结构解释的经典性质的HU抑制负超螺旋DNA。
We determined the crystal structure of the Escherichia coli nucleoid-associated HU alpha beta protein by x-ray diffraction and observed that the heterodimers form multimers with octameric units in three potential arrangements, which may serve specialized roles in different DNA transaction reactions. It is of special importance that one of the structures forms spiral filaments with left-handed rotations. A negatively superhelical DNA can be modeled to wrap around this left-handed HU alpha beta multimer. Whereas the wild-type HU generated negative DNA supercoiling in vitro, an engineered heterodimer with an altered amino acid residue critical for the formation of the left-handed spiral protein in the crystal was defective in the process, thus providing the structural explanation for the classical property of HU to restrain negative supercoils in DNA.