ジャーナル: Nature / 年: 2019 タイトル: CasX enzymes comprise a distinct family of RNA-guided genome editors. 著者: Jun-Jie Liu / Natalia Orlova / Benjamin L Oakes / Enbo Ma / Hannah B Spinner / Katherine L M Baney / Jonathan Chuck / Dan Tan / Gavin J Knott / Lucas B Harrington / Basem Al-Shayeb / ...著者: Jun-Jie Liu / Natalia Orlova / Benjamin L Oakes / Enbo Ma / Hannah B Spinner / Katherine L M Baney / Jonathan Chuck / Dan Tan / Gavin J Knott / Lucas B Harrington / Basem Al-Shayeb / Alexander Wagner / Julian Brötzmann / Brett T Staahl / Kian L Taylor / John Desmarais / Eva Nogales / Jennifer A Doudna / 要旨: The RNA-guided CRISPR-associated (Cas) proteins Cas9 and Cas12a provide adaptive immunity against invading nucleic acids, and function as powerful tools for genome editing in a wide range of ...The RNA-guided CRISPR-associated (Cas) proteins Cas9 and Cas12a provide adaptive immunity against invading nucleic acids, and function as powerful tools for genome editing in a wide range of organisms. Here we reveal the underlying mechanisms of a third, fundamentally distinct RNA-guided genome-editing platform named CRISPR-CasX, which uses unique structures for programmable double-stranded DNA binding and cleavage. Biochemical and in vivo data demonstrate that CasX is active for Escherichia coli and human genome modification. Eight cryo-electron microscopy structures of CasX in different states of assembly with its guide RNA and double-stranded DNA substrates reveal an extensive RNA scaffold and a domain required for DNA unwinding. These data demonstrate how CasX activity arose through convergent evolution to establish an enzyme family that is functionally separate from both Cas9 and Cas12a.