Lynch Thomas W, Read Erik K, Mattis Aras N, Gardner Jeffrey F, Rice Phoebe A
Department of Biochemistry and Molecular Biology, The University of Chicago, 920 E 58th Street CLSC 221, Chicago, IL 60637, USA.
J Mol Biol. 2003 Jul 11;330(3):493-502. doi: 10.1016/s0022-2836(03)00529-1.
Integration host factor (IHF) is a DNA-bending protein that recognizes its cognate sites through indirect readout. Previous studies have shown that binding of wild-type (WT)-IHF is disrupted by a T to A mutation at the center position of a conserved TTR motif in its binding site, and that substitution of betaGlu44 with Ala prevented IHF from discriminating between A and T at this position. We have determined the crystal structures and relative binding affinities for all combinations of WT-IHF and IHF-betaGlu44Ala bound to the WT and mutant DNAs. Comparison of these structures reveals that DNA twist plays a major role in DNA recognition by IHF, and that this geometric parameter is dependent on the dinucleotide step and not on the bound IHF variant.
整合宿主因子(IHF)是一种通过间接识别来识别其同源位点的DNA弯曲蛋白。先前的研究表明,野生型(WT)-IHF的结合会因其结合位点中保守TTR基序中心位置的T到A突变而受到干扰,并且用Ala取代βGlu44会阻止IHF在该位置区分A和T。我们已经确定了WT-IHF和IHF-βGlu44Ala与野生型和突变型DNA结合的所有组合的晶体结构和相对结合亲和力。这些结构的比较表明,DNA扭曲在IHF对DNA的识别中起主要作用,并且这个几何参数取决于二核苷酸步长而不是结合的IHF变体。