Structural analysis of ternary complexes of vaccinia RNA polymerase.
Structural analysis of ternary complexes of vaccinia RNA polymerase.
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痘苗病毒 RNA 聚合酶三元复合物的结构分析。
DOI：
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发表时间：
1992
影响因子：
11.1
通讯作者：
S. Shuman
中科院分区：
文献类型：
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作者：
J. Hagler;S. Shuman
用DNase I足迹法检测了停在离散模板位置的牛痘RNA聚合酶伸长复合体的结构。足迹的前沿与催化模板位置具有恒定的关系，在非模板链上预先为22-24个核苷酸(NT)，在模板链上为17个核苷酸(NT)。DNA酶对前缘的非模板链高度敏感，这表明DNA在进入聚合酶分子时可能发生了扭曲。由腺苷残基对焦碳酸酯的反应表明，DNA在转录泡处的解离区域从催化中心延伸了至少12nt5‘。位于生长点13个5‘和4个3’的铜-邻菲咯啉敏感部位似乎是气泡边缘的分界线。泡泡内化学修饰的链不对称与不超过10个碱基对的RNA-DNA杂交一致。
The structure of the elongation complex of vaccinia RNA polymerase halted at discrete template positions was examined by DNase I footprinting. The leading edge of the footprint bore a constant relationship to the catalytic template position, being 22-24 nucleotides (nt) in advance on the nontemplate strand and 17 nt on the template strand. DNase hypersensitivity of the nontemplate strand at the leading edge suggested that the DNA might be distorted as it entered the polymerase molecule. The region of DNA unwinding at the transcription bubble extended at least 12 nt 5' from the catalytic center, as indicated by the reactivity of adenosine residues to diethylpyrocarbonate. Cu-phenanthroline-hypersensitive sites located 13 nt 5' and 4 nt 3' of the growing point appeared to demarcate the margins of the bubble. Strand asymmetry of chemical modification within the bubble was consistent with an RNA-DNA hybrid of no more than 10 base pairs.