Pontiggia A, Negri A, Beltrame M, Bianchi M E
Istituto Scientifico Ospedale San Raffaele, Milano, Italy.
Mol Microbiol. 1993 Feb;7(3):343-50. doi: 10.1111/j.1365-2958.1993.tb01126.x.
We have purified the main four-way junction DNA-binding protein of Escherichia coli, and have found it to be the well-known HU protein. HU protein recognizes with high-affinity one of the angles present in the junction, a molecule with the shape of an X. Other DNA structures characterized by sharp bends or kinks, like bulged duplex DNAs containing unpaired bases, are also bound. HU protein appears to inhibit cruciform extrusion from supercoiled inverted repeat (palindromic) DNA, either by constraining supercoiling or by trapping a metastable interconversion intermediate. All these properties are analogous to the properties of the mammalian chromatin protein HMG1. We suggest that HU is a prokaryotic HMG1-like protein rather than a histone-like protein.
我们已经纯化了大肠杆菌的主要四向连接点DNA结合蛋白，发现它就是著名的HU蛋白。HU蛋白以高亲和力识别连接点中存在的一个角，该分子呈X形。其他以急剧弯曲或扭结为特征的DNA结构，如含有未配对碱基的凸起双链DNA，也能与之结合。HU蛋白似乎通过限制超螺旋或捕获亚稳态的相互转化中间体来抑制超螺旋反向重复（回文）DNA的十字形挤出。所有这些特性都与哺乳动物染色质蛋白HMG1的特性相似。我们认为HU是一种原核类HMG1蛋白，而不是类组蛋白。
