噬菌体λ Cro蛋白与OR3操纵基因相互作用的1H核磁共振研究。结合时OR3操纵基因构象变化的证据。
1H NMR study of the interaction of bacteriophage lambda Cro protein with the OR3 operator. Evidence for a change of the conformation of the OR3 operator on binding.
作者信息
Kirpichnikov M P, Hahn K D, Buck F, Rüterjans H, Chernov B K, Kurochkin A V, Skryabin K G, Bayev A A
出版信息
Nucleic Acids Res. 1984 Apr 25;12(8):3551-61. doi: 10.1093/nar/12.8.3551.
The specific complex between the lambda phage OR3 operator and the Cro protein has been studied by proton NMR spectroscopy at 500 MHz. The DNA imino proton resonances of this complex have been assigned to specific base pairs using the known assignments of these resonances for the free operator. Increase of the protein/DNA ratio to complete saturation of the OR3 operator with the Cro protein made it possible to follow the shift changes of the resonances. Ambiguities were resolved by nuclear Overhauser effect measurements on the complex. The shifts of the imino proton resonance positions provide information on the changes induced in the conformation of the operator upon complex formation with a dimer of the Cro protein. The most striking shift occurs for the central (GC 9) base pair, which is known to have no direct contacts with the Cro protein. This shift may be induced by a bend in the OR3 operator DNA at the GC 9 base pair to accommodate the operator for the binding of the Cro protein dimer. The imino proton resonances of two additional base pairs can be observed in the complex, demonstrating an overall stabilization of the DNA structure by the binding of the Cro protein.
利用500兆赫的质子核磁共振光谱对λ噬菌体OR3操纵基因与Cro蛋白之间的特定复合物进行了研究。该复合物的DNA亚氨基质子共振峰已根据游离操纵基因这些共振峰的已知归属，被指定到特定碱基对。将蛋白质/DNA比例提高到使OR3操纵基因完全被Cro蛋白饱和的程度，从而能够追踪共振峰的位移变化。通过对该复合物进行核Overhauser效应测量，解决了模糊性问题。亚氨基质子共振峰位置的位移提供了关于操纵基因与Cro蛋白二聚体形成复合物时其构象变化的信息。最显著的位移发生在中心（GC 9）碱基对处，已知该碱基对与Cro蛋白没有直接接触。这种位移可能是由OR3操纵基因DNA在GC 9碱基对处的弯曲引起的，以便使操纵基因适应Cro蛋白二聚体的结合。在该复合物中还可观察到另外两个碱基对的亚氨基质子共振峰，这表明Cro蛋白的结合使DNA结构总体上更加稳定。
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