The structural basis of differential DNA sequence recognition by restriction-modification controller proteins
The structural basis of differential DNA sequence recognition by restriction-modification controller proteins
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DOI：
10.1093/nar/gks718
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发表时间：
2012-11-01
影响因子：
14.9
通讯作者：
Kneale, G. G.
中科院分区：
文献类型：
--
作者：
Ball, N. J.;McGeehan, J. E.;Kneale, G. G.
控制蛋白（C）在多种限制修饰（RM）系统中调节RM基因的表达。然而，RM系统Esp 1396 I是特别感兴趣的，因为C蛋白调节限制性内切核酸酶（R）基因和甲基转移酶（M）基因。这种精细调节的遗传开关的机制取决于控制R和M基因的启动子的差异结合亲和力，这反过来又取决于差异DNA序列识别和识别双重对称性的能力。我们在这里报告的晶体结构的C蛋白结合到M启动子，并比较每个操作序列的表面等离子体共振的结合亲和力。M启动子处的转录抑制复合物与R启动子处的转录激活复合物的结构的比较显示了蛋白质-DNA相互作用中的微妙变化（由蛋白质中的小构象变化所支持）如何能够解释基因表达的差异调节的分子基础。
Controller (C) proteins regulate the expression of restriction-modification (RM) genes in a wide variety of RM systems. However, the RM system Esp1396I is of particular interest as the C protein regulates both the restriction endonuclease (R) gene and the methyltransferase (M) gene. The mechanism of this finely tuned genetic switch depends on differential binding affinities for the promoters controlling the R and M genes, which in turn depends on differential DNA sequence recognition and the ability to recognize dual symmetries. We report here the crystal structure of the C protein bound to the M promoter, and compare the binding affinities for each operator sequence by surface plasmon resonance. Comparison of the structure of the transcriptional repression complex at the M promoter with that of the transcriptional activation complex at the R promoter shows how subtle changes in protein-DNA interactions, underpinned by small conformational changes in the protein, can explain the molecular basis of differential regulation of gene expression.