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Structures of a RAG-like transposase during cut-and-paste transposition
Nature ( IF 50.5 ) Pub Date : 2019-11-13 , DOI: 10.1038/s41586-019-1753-7
Chang Liu 1 , Yang Yang 2, 3 , David G Schatz 1
Affiliation  

Transposons have had a pivotal role in genome evolution1 and are believed to be the evolutionary progenitors of the RAG1–RAG2 recombinase2, an essential component of the adaptive immune system in jawed vertebrates3. Here we report one crystal structure and five cryo-electron microscopy structures of Transib4,5, a RAG1-like transposase from Helicoverpa zea, that capture the entire transposition process from the apo enzyme to the terminal strand transfer complex with transposon ends covalently joined to target DNA, at resolutions of 3.0–4.6 Å. These structures reveal a butterfly-shaped complex that undergoes two cycles of marked conformational changes in which the ‘wings’ of the transposase unfurl to bind substrate DNA, close to execute cleavage, open to release the flanking DNA and close again to capture and attack target DNA. Transib possesses unique structural elements that compensate for the absence of a RAG2 partner, including a loop that interacts with the transposition target site and an accordion-like C-terminal tail that elongates and contracts to help to control the opening and closing of the enzyme and assembly of the active site. Our findings reveal the detailed reaction pathway of a eukaryotic cut-and-paste transposase and illuminate some of the earliest steps in the evolution of the RAG recombinase.Analysis of multiple structures of the Helicoverpa zea DNA transposase Transib, determined by X-ray crystallography and cryo-electron microscopy, reveals the detailed pathway of the transposition reaction and sheds light on the evolution of the RAG recombinase.

中文翻译:


剪切粘贴转座过程中 RAG 样转座酶的结构



转座子在基因组进化中发挥着关键作用,被认为是 RAG1-RAG2 重组酶的进化祖细胞,而 RAG1-RAG2 重组酶是有颌脊椎动物适应性免疫系统的重要组成部分。在这里,我们报道了 Transib4,5 的一个晶体结构和五个冷冻电镜结构,Transib4,5 是一种来自玉米夜蛾的 RAG1 样转座酶,它捕获了从 apo 酶到末端链转移复合物的整个转座过程,其中转座子末端共价连接到靶标DNA,分辨率为 3.0–4.6 Å。这些结构揭示了一个蝴蝶形复合物,经历两个显着构象变化的循环,其中转座酶的“翅膀”展开以结合底物DNA,关闭以执行切割,打开以释放侧翼DNA并再次关闭以捕获和攻击目标脱氧核糖核酸。 Transib 拥有独特的结构元件,可补偿 RAG2 伴侣的缺失,包括与转座靶位点相互作用的环,以及可伸长和收缩以帮助控制酶的打开和关闭的手风琴状 C 末端尾部,活性位点的组装。我们的研究结果揭示了真核剪切粘贴转座酶的详细反应途径,并阐明了 RAG 重组酶进化中的一些最早步骤。通过 X 射线晶体学和确定的 Helicoverpa zea DNA 转座酶 Transib 的多种结构分析冷冻电子显微镜揭示了转座反应的详细途径,并揭示了 RAG 重组酶的进化。
更新日期:2019-11-13
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