CasX enzymes comprise a distinct family of RNA-guided genome editors

Liu, Jun-Jie; Orlova, Natalia; Oakes, Benjamin L.; Ma, Enbo; Spinner, Hannah B.; Baney, Katherine L. M.; Chuck, Jonathan; Tan, Dan; Knott, Gavin J.; Harrington, Lucas B.; Al-Shayeb, Basem; Wagner, Alexander; Broetzmann, Julian; Staahl, Brett T.; Taylor, Kian L.; Desmarais, John; Nogales, Eva und Doudna, Jennifer A. (2019): CasX enzymes comprise a distinct family of RNA-guided genome editors. In: Nature, Bd. 566, Nr. 7743

Abstract

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.

• Dokumententyp: Zeitschriftenartikel
• Fakultät: Chemie und Pharmazie
• Themengebiete: 500 Naturwissenschaften und Mathematik > 540 Chemie
• ISSN: 0028-0836
• Sprache: Englisch