Biomolecular Structure Group, Institute of Biomedical and Biomolecular Sciences, School of Biological Sciences, University of Portsmouth, Portsmouth, Hampshire PO1 2DY, UK.
Nucleic Acids Res. 2012 May;40(9):4158-67. doi: 10.1093/nar/gkr1250. Epub 2011 Dec 30.
The controller protein C.Esp1396I regulates the timing of gene expression of the restriction-modification (RM) genes of the RM system Esp1396I. The molecular recognition of promoter sequences by such transcriptional regulators is poorly understood, in part because the DNA sequence motifs do not conform to a well-defined symmetry. We report here the crystal structure of the controller protein bound to a DNA operator site. The structure reveals how two different symmetries within the operator are simultaneously recognized by the homo-dimeric protein, underpinned by a conformational change in one of the protein subunits. The recognition of two different DNA symmetries through movement of a flexible loop in one of the protein subunits may represent a general mechanism for the recognition of pseudo-symmetric DNA sequences.
控制器蛋白 C.Esp1396I 调节限制修饰（RM）系统 Esp1396I 的基因表达的时间。这种转录调节剂对启动子序列的分子识别还不太清楚，部分原因是 DNA 序列基序不符合明确的对称性。我们在此报告结合到 DNA 操作子位点的控制器蛋白的晶体结构。该结构揭示了同二聚体蛋白如何同时识别操作子中的两个不同的对称性，这是由一个蛋白质亚基的构象变化支撑的。通过一个蛋白质亚基中的柔性环的运动来识别两个不同的 DNA 对称性，可能代表识别伪对称 DNA 序列的一般机制。
