Structural Basis for DNA-Hairpin Promoter Recognition by the Bacteriophage N4 Virion RNA Polymerase
Structural Basis for DNA-Hairpin Promoter Recognition by the Bacteriophage N4 Virion RNA Polymerase
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DOI：
10.1016/j.molcel.2008.11.010
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发表时间：
2008-12-05
期刊：
影响因子：
16
通讯作者：
Murakami, Katsuhiko S.
中科院分区：
文献类型：
--
作者：
Gleghorn, Michael L.;Davydova, Elena K.;Murakami, Katsuhiko S.
Coliphage N4 病毒体衣壳化 RNA 聚合酶 (vRNAP) 是噬菌体 T7 样单亚基 RNA 聚合酶 (RNAP) 家族的成员。其中心结构域 (mini-vRNAP) 包含全长 vRNAP 的所有 RNAP 功能，可识别 5 至 7 碱基对茎和 3 核苷酸环发夹 DNA 启动子。这里？我们报告了与启动子结合的 mini-vRNAP 的 X 射线晶体结构。水貂 vRNAP 使用四个结构基序来识别毛发环和茎中的 DNA 序列，并解开 DNA。尽管它们的序列相似性较低，但与识别双链 DNA 启动子的 T7 RNAP 共享四个基序中的三组。二元复合物结构和工程化二硫键实验的结果表明，阻断模板DNA进入apo形式mini-vRNAP活性位点的插头和基序B环在启动子结合时经历大规模构象变化，解释了对于N4噬菌体早期转录至关重要的受限启动子特异性。
Coliphage N4 virion-encapsidated RNA polymerase (vRNAP) is a member of the phage T7-like single-subunit RNA polymerase (RNAP) family. Its central domain (mini-vRNAP) contains all RNAP functions of the full-length vRNAP, which recognizes a 5 to 7 base pair stem and 3 nucleotide loop hairpin DNA promoter. Here? we report the X-ray crystal structures of mini-vRNAP bound to promoters. Mink vRNAP uses four structural motifs to recognize DNA sequences at the hair in loop and stem and to unwind DNA, Despite their low sequence similarity, three put of four motifs are shared with, T7 RNAP that recognizes a double-stranded DNA promoter. The binary complex structure and results of engineered disulfide linkage experiments reveal that the plug and motif B loop, which block the access of template DNA to the active site in the apo-form mini-vRNAP, undergo a large-scale conformational change upon in promoter binding, explaining the restricted promoter specificity that is critical for N4 phage early transcription.