RNA polymerase and transcription elongation factor Spt4/5 complex structure
RNA polymerase and transcription elongation factor Spt4/5 complex structure
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DOI：
10.1073/pnas.1013828108
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发表时间：
2011-01-11
影响因子：
11.1
通讯作者：
Murakami, Katsuhiko S.
中科院分区：
文献类型：
--
作者：
Klein, Brianna J.;Bose, Daniel;Murakami, Katsuhiko S.
古细菌和真核生物中的 Spt4/5 及其细菌同源物 NusG 是生命所有三个领域中唯一保守的延伸因子，在共转录调节和招募其他因子到延伸 RNA 聚合酶中发挥着许多关键作用。在这里，我们使用冷冻电子显微镜重建和单颗粒分析展示了 Spt4/5 的晶体结构以及 RNA 聚合酶-Spt4/5 复合物的结构。 Spt4/5 结合在 RNA 聚合酶爪的中间并包围 DNA，让人想起 DNA 聚合酶夹和环解旋酶。转录延伸复合体模型揭示Spt4/5是上游DNA持有者并接触转录泡中的非模板DNA。这些结构表明，细胞 RNA 聚合酶还使用环绕 DNA 的策略来增强其持续合成能力，正如许多核酸加工酶（包括 DNA 聚合酶和解旋酶）中常见的那样。
Spt4/5 in archaea and eukaryote and its bacterial homolog NusG is the only elongation factor conserved in all three domains of life and plays many key roles in cotranscriptional regulation and in recruiting other factors to the elongating RNA polymerase. Here, we present the crystal structure of Spt4/5 as well as the structure of RNA polymerase-Spt4/5 complex using cryoelectron microscopy reconstruction and single particle analysis. The Spt4/5 binds in the middle of RNA polymerase claw and encloses the DNA, reminiscent of the DNA polymerase clamp and ring helicases. The transcription elongation complex model reveals that the Spt4/5 is an upstream DNA holder and contacts the nontemplate DNA in the transcription bubble. These structures reveal that the cellular RNA polymerases also use a strategy of encircling DNA to enhance its processivity as commonly observed for many nucleic acid processing enzymes including DNA polymerases and helicases.