Somers W S, Phillips S E
Department of Biochemistry and Molecular Biology, University of Leeds, UK.
Nature. 1992 Oct 1;359(6394):387-93. doi: 10.1038/359387a0.
The crystal structure of the met repressor-operator complex shows two dimeric repressor molecules bound to adjacent sites 8 base pairs apart on an 18-base-pair DNA fragment. Sequence specificity is achieved by insertion of double-stranded antiparallel protein beta-ribbons into the major groove of B-form DNA, with direct hydrogen-bonding between amino-acid side chains and the base pairs. The repressor also recognizes sequence-dependent distortion or flexibility of the operator phosphate backbone, conferring specificity even for inaccessible base pairs.
甲硫氨酸阻遏蛋白-操纵基因复合物的晶体结构显示，两个二聚体阻遏蛋白分子与一个18碱基对的DNA片段上相距8个碱基对的相邻位点结合。序列特异性是通过将双链反平行蛋白质β-折叠插入B型DNA的大沟中实现的，氨基酸侧链与碱基对之间存在直接氢键。阻遏蛋白还识别操纵基因磷酸主链的序列依赖性扭曲或灵活性，即使对于无法接近的碱基对也能赋予特异性。
