Solution structure of P22 transcriptional antitermination N peptide box B RNA complex
Solution structure of P22 transcriptional antitermination N peptide box B RNA complex
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DOI：
10.1038/nsb0398-203
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发表时间：
1998-03-01
期刊：
影响因子：
--
通讯作者：
Patel, DJ
中科院分区：
文献类型：
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作者：
Cai, ZP;Gorin, A;Patel, DJ
我们已经确定了一个15-mer的boxB RNA发夹与参与噬菌体P22转录抗终止的N蛋白的20-mer基本肽络合的溶液结构。复合物的形成包括与N肽的适应性结合，采用弯曲的α -螺旋构象，通过疏水和静电相互作用紧密地包裹在boxB RNA发夹的主要凹槽面，定向开放的相反面，以便与宿主因子和/或RNA聚合酶进行潜在的相互作用。boxB RNA发夹五环中的四个核苷酸在复合体形成时形成了一个稳定的类似GNRA的四环结构支架，允许环出的第五个核苷酸与结合的肽进行广泛的疏水接触。关键精氨酸的鸟嘌呤基团在环闭合剪切的G.A错配中与鸟嘌呤和相邻的主磷酸键形成氢键。鉴定的分子间接触解释了N肽和boxB RNA突变对噬菌体转录抗终止的影响。
We have determined the solution structure of a 15-mer boxB RNA hairpin complexed with a 20-mer basic peptide of the N protein involved in bacteriophage P22 transcriptional antitermination. Complex formation involves adaptive binding with the N peptide adopting a bent therefore alpha-helical conformation that packs tightly through hydrophobic and electrostatic interactions against the major groove face of the boxB RNA hairpin, orienting the open opposite face for potential interactions with host factors and/or RNA polymerase. Four nucleotides in the boxB RNA hairpin pentaloop form a stable GNRA like tetraloop structural scaffold on complex formation, allowing the looped out fifth nucleotide to make extensive hydrophobic contacts with the bound peptide. The guanidinium group of a key arginine is hydrogen-bonded to the guanine in a loop-closing sheared G.A mismatch and to adjacent backbone phosphates. The identified intermolecular contacts account for the consequences of N peptide and boxB RNA mutations on bacteriophage transcriptional antitermination.