在CRISPR-Cas适应性免疫过程中捕获外来DNA
James K Nuñez1, Lucas B Harrington1, Philip J Kranzusch1,2
1Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California 94720, USA.
Nature
|October 28, 2015
概括
细菌和古生物通过整合外来DNA来防御病毒使用CRISPR免疫力. 研究人员揭示了Cas1-Cas2酶复合物如何捕获DNA, 作为CRISPR位置结构的分子统治者.
科学领域:
- 分子生物学
- 微生物遗传学
- 结构生物学
背景情况:
- 细菌和古生物对菌体和质粒具有适应性免疫系统.
- 这种免疫包括将外来DNA片段 (间隔器) 整合到CRISPR位点中.
- Cas1-Cas2整合酶复合体对于获得这些隔离器至关重要.
研究的目的:
- 阐明Cas1-Cas2复合体选择外来DNA基质的机制.
- 了解CRISPR免疫中的间隔器获取的结构基础.
- 揭示Cas1-Cas2如何作为CRISPR位形成的分子统治者.
主要方法:
- 使用X射线结晶学来确定大肠杆菌Cas1-Cas2复合物的结构.
- 这项研究涉及分析与33核酸原空间体DNA基质结合的复合物.
- 解释结构数据以了解蛋白质- DNA 相互作用和基质选择.
主要成果:
- Cas1-Cas2复合体形成一个曲的结合表面,跨越原体空间DNA的整个长度.
- 该复合体将DNA末端分离,将终端3'-OH组定位在Cas1活性位点内进行核友攻击.
- DNA与蛋白质复合体之间的基体相互作用解释了观察到的序列非特异性基质选择.
结论:
- 这项研究揭示了外来DNA被Cas1-Cas2复合体捕获的结构基础.
- 它揭示了Cas1-Cas2作为分子统治者的机制,
- 这些发现提供了关于 prokaryotes 适应性免疫的基本过程的关键见解.
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