Engelhorn M, Boccard F, Murtin C, Prentki P, Geiselmann J
Department of Molecular Biology, University of Geneva, Switzerland.
Nucleic Acids Res. 1995 Sep 11;23(17):2959-65.
The histone-like protein integration host factor (IHF) of Escherichia coli binds to specific binding sites on the chromosome or on mobile genetic elements, and is involved in many cellular processes. We have analyzed the interaction of IHF with five different binding sites in vitro and in vivo using UV laser footprinting, a technique that probes the immediate environment and conformation of a segment of DNA. Using this generally applicable technique we can directly compare the binding modes and interaction strengths of a DNA binding protein in its physiological environment within the cell to measurements performed in vitro. We conclude that the interactions between IHF and its specific binding sites are identical in vitro and in vivo. The footprinting signal is consistent with the model of IHF-binding to DNA proposed by Yang and Nash (1989). The occupancy of binding sites varies with the concentration of IHF in the cell and allows to estimate the concentration of free IHF protein in the cell.
大肠杆菌的组蛋白样蛋白整合宿主因子（IHF）可与染色体或移动遗传元件上的特定结合位点结合，并参与许多细胞过程。我们使用紫外线激光足迹法，在体外和体内分析了IHF与五个不同结合位点的相互作用，该技术可探测一段DNA的紧邻环境和构象。通过这种普遍适用的技术，我们可以直接将细胞内生理环境中DNA结合蛋白的结合模式和相互作用强度与体外测量结果进行比较。我们得出结论，IHF与其特定结合位点之间的相互作用在体外和体内是相同的。足迹信号与Yang和Nash（1989年）提出的IHF与DNA结合模型一致。结合位点的占有率随细胞中IHF的浓度而变化，并可用于估计细胞中游离IHF蛋白的浓度。
