Giladi H, Gottesman M, Oppenheim A B
Department of Molecular Genetics, Hebrew University-Hadassah Medical School, Jerusalem, Israel.
J Mol Biol. 1990 May 5;213(1):109-21. doi: 10.1016/S0022-2836(05)80124-X.
Escherichia coli integration host factor (IHF) is a small dimeric protein that binds to a specific DNA consensus sequence and produces DNA bending. Transcription from the bacteriophage lambda pL promoter is stimulated three- to fourfold by IHF both in vivo and in vitro. IHF binds with high-affinity to two tandem sites located just upstream from the pL promoter and enhances the formation of RNA polymerase-promoter closed complexes. The rate of isomerization to open complex is not influenced by IHF. IHF may stimulate recognition of pL by one or more of several mechanisms: (1) by bending DNA; (2) by making protein-protein contacts with RNA polymerase; or (3) by occluding a competing promoter upstream from pL.
大肠杆菌整合宿主因子（IHF）是一种小的二聚体蛋白，它与特定的DNA共有序列结合并使DNA弯曲。在体内和体外，噬菌体λ pL启动子的转录都被IHF刺激三到四倍。IHF以高亲和力结合到位于pL启动子上游的两个串联位点，并增强RNA聚合酶-启动子封闭复合物的形成。向开放复合物的异构化速率不受IHF影响。IHF可能通过以下几种机制中的一种或多种来刺激对pL的识别：（1）通过使DNA弯曲；（2）通过与RNA聚合酶进行蛋白质-蛋白质接触；或（3）通过封闭pL上游的竞争性启动子。
