Midwest Center for Structural Genomics and Structural Biology Center, Biosciences, Argonne National Laboratory, 9700 South Cass Avenue, Building 202, Argonne, IL 60439, USA.
Proc Natl Acad Sci U S A. 2011 Jun 21;108(25):10109-14. doi: 10.1073/pnas.1106840108. Epub 2011 May 31.
HetR is an essential regulator of heterocyst development in cyanobacteria. HetR binds to a DNA palindrome upstream of the hetP gene. We report the crystal structure of HetR from Fischerella at 3.0 Å. The protein is a dimer comprised of a central DNA-binding unit containing the N-terminal regions of the two subunits organized with two helix-turn-helix motifs; two globular flaps extending in opposite directions; and a hood over the central core formed from the C-terminal subdomains. The flaps and hood have no structural precedent in the protein database, therefore representing new folds. The structural assignments are supported by site-directed mutagenesis and DNA-binding studies. We suggest that HetR serves as a scaffold for assembly of transcription components critical for heterocyst development.
HetR 是蓝藻异形胞发育的必需调控因子。HetR 与 hetP 基因上游的 DNA 回文序列结合。我们报道了 Fischerella 中 HetR 的晶体结构，分辨率为 3.0Å。该蛋白是由两个亚基的中心 DNA 结合单元组成的二聚体，包含两个螺旋-转角-螺旋基序；两个向相反方向延伸的球状瓣；以及由 C 末端亚结构域形成的中央核心上的罩。这些瓣和罩在蛋白质数据库中没有结构先例，因此代表了新的折叠。结构分配得到了定点突变和 DNA 结合研究的支持。我们认为 HetR 作为转录组件组装的支架，这些转录组件对于异形胞发育至关重要。
