Makino K, Amemura M, Kawamoto T, Kimura S, Shinagawa H, Nakata A, Suzuki M
Research Institute for Microbial Diseases, Osaka University, Suita, Japan.
J Mol Biol. 1996 May 31;259(1):15-26. doi: 10.1006/jmbi.1996.0298.
We have identified the DNA-binding domain (DBD) of an Escherichia coli activator protein PhoB as its C-terminal 91 residues. Four amino acid positions in the PhoB DBD are found important for interaction with the RNA polymerase holoenzyme that contains the sigma 70 subunit. Assuming that the PhoB DBD is structurally similar to the histone H5 DBD, the four positions are placed around the turn region that connects two putative helices, 2 and 3 (helix 3 is likely to be the recognition helix). The binding sites of PhoB, three with the sequence TGTCA and one of TTACA, are identified in the pstS promoter. The pstS promoter has intrinsic bending (or bendability), which is much enhanced upon binding PhoB. On the basis of the above, some aspects of the PhoB-DNA-RNA polymerase interaction are discussed.
我们已确定大肠杆菌激活蛋白PhoB的DNA结合结构域（DBD）为其C端的91个氨基酸残基。发现PhoB DBD中的四个氨基酸位置对于与包含σ70亚基的RNA聚合酶全酶的相互作用很重要。假设PhoB DBD在结构上与组蛋白H5 DBD相似，这四个位置位于连接两个假定螺旋（螺旋2和螺旋3，螺旋3可能是识别螺旋）的转角区域周围。在pstS启动子中鉴定出PhoB的结合位点，三个序列为TGTCA，一个为TTACA。pstS启动子具有内在弯曲性（或可弯曲性），在结合PhoB后会大大增强。基于上述内容，讨论了PhoB-DNA-RNA聚合酶相互作用的一些方面。
