Structural basis of DNA targeting by a transposon-encoded CRISPR-Cas system

doi:10.1038/s41586-019-1849-0

GSTDTAP > 地球科学

DOI	10.1038/s41586-019-1849-0
	Structural basis of DNA targeting by a transposon-encoded CRISPR-Cas system
	Halpin-Healy, Tyler S.; Klompe, Sanne E.; Sternberg, Samuel H.; Fernandez, Israel S.
	2020-06-01
发表期刊	NATURE
ISSN	0028-0836
EISSN	1476-4687
出版年	2020
卷号	577 期号:7789 页码:271-+
文章类型	Article
语种	英语
国家	USA
英文关键词	Bacteria use adaptive immune systems encoded by CRISPR and Cas genes to maintain genomic integrity when challenged by pathogens and mobile genetic elements(1-3). Type I CRISPR-Cas systems typically target foreign DNA for degradation via joint action of the ribonucleoprotein complex Cascade and the helicase-nuclease Cas3(4,5), but nuclease-deficient type I systems lacking Cas3 have been repurposed for RNA-guided transposition by bacterial Tn7-like transposons(6,7). How CRISPR- and transposon-associated machineries collaborate during DNA targeting and insertion remains unknown. Here we describe structures of a TniQ-Cascade complex encoded by the Vibrio cholerae Tn6677 transposon using cryo-electron microscopy, revealing the mechanistic basis of this functional coupling. The cryo-electron microscopy maps enabled de novo modelling and refinement of the transposition protein TniQ, which binds to the Cascade complex as a dimer in a head-to-tail configuration, at the interface formed by Cas6 and Cas7 near the 3' end of the CRISPR RNA (crRNA). The natural Cas8-Cas5 fusion protein binds the 5' crRNA handle and contacts the TniQ dimer via a flexible insertion domain. A target DNA-bound structure reveals critical interactions necessary for protospacer-adjacent motif recognition and R-loop formation. This work lays the foundation for a structural understanding of how DNA targeting by TniQ-Cascade leads to downstream recruitment of additional transposase proteins, and will guide protein engineering efforts to leverage this system for programmable DNA insertions in genome-engineering applications.
领域	地球科学 ; 气候变化 ; 资源环境
收录类别	SCI-E
WOS记录号	WOS:000506682500047
WOS关键词	GUIDED SURVEILLANCE COMPLEX ; CRYO-EM ; CRYSTAL-STRUCTURE ; REFINEMENT ; MECHANISMS
WOS类目	Multidisciplinary Sciences
WOS研究方向	Science & Technology - Other Topics
引用统计
文献类型	期刊论文
条目标识符	http://119.78.100.173/C666/handle/2XK7JSWQ/281030
专题	地球科学资源环境科学气候变化
作者单位	Columbia Univ, Dept Biochem & Mol Biophys, New York, NY 10027 USA
推荐引用方式 GB/T 7714	Halpin-Healy, Tyler S.,Klompe, Sanne E.,Sternberg, Samuel H.,et al. Structural basis of DNA targeting by a transposon-encoded CRISPR-Cas system[J]. NATURE,2020,577(7789):271-+.
APA	Halpin-Healy, Tyler S.,Klompe, Sanne E.,Sternberg, Samuel H.,&Fernandez, Israel S..(2020).Structural basis of DNA targeting by a transposon-encoded CRISPR-Cas system.NATURE,577(7789),271-+.
MLA	Halpin-Healy, Tyler S.,et al."Structural basis of DNA targeting by a transposon-encoded CRISPR-Cas system".NATURE 577.7789(2020):271-+.