Type III CRISPR-Cas complexes act as protein-assisted ribozymes during target RNA cleavage.

Autor:	Schwartz EA; Interdisciplinary Life Sciences Graduate Programs, University of Texas at Austin., Bravo JPK; Department of Molecular Biosciences, University of Texas at Austin., Ahsan M; Department of Bioengineering and Department of Chemistry, University of California, Riverside., Macias LA; Department of Chemistry, University of Texas at Austin., McCafferty CL; Interdisciplinary Life Sciences Graduate Programs, University of Texas at Austin., Dangerfield TL; Department of Molecular Biosciences, University of Texas at Austin., Walker JN; Department of Chemistry, University of Texas at Austin., Brodbelt JS; Department of Chemistry, University of Texas at Austin., Palermo G; Department of Bioengineering and Department of Chemistry, University of California, Riverside., Fineran PC; Microbiology and Immunology, University of Otago, PO Box 56, Dunedin 9054, New Zealand.; Bioprotection Aotearoa, University of Otago, PO Box 56, Dunedin 9054, New Zealand.; Genetics Otago, University of Otago, PO Box 56, Dunedin 9054, New Zealand., Fagerlund RD; Microbiology and Immunology, University of Otago, PO Box 56, Dunedin 9054, New Zealand.; Bioprotection Aotearoa, University of Otago, PO Box 56, Dunedin 9054, New Zealand.; Genetics Otago, University of Otago, PO Box 56, Dunedin 9054, New Zealand., Taylor DW; Interdisciplinary Life Sciences Graduate Programs, University of Texas at Austin.; Department of Molecular Biosciences, University of Texas at Austin.; Center for Systems and Synthetic Biology, University of Texas at Austin.; LIVESTRONG Cancer Institutes, Dell Medical School, University of Texas at Austin.
Jazyk:	angličtina
Zdroj:	Research square [Res Sq] 2023 Apr 27. Date of Electronic Publication: 2023 Apr 27.
DOI:	10.21203/rs.3.rs-2837968/v1
Abstrakt:	CRISPR-Cas systems are an adaptive immune system in bacteria and archaea that utilize CRISPR RNA-guided surveillance complexes to target complementary RNA or DNA for destruction 1-5 . Target RNA cleavage at regular intervals is characteristic of type III effector complexes; however, the mechanism has remained enigmatic 6,7 . Here, we determine the structures of the Synechocystis type III-Dv complex, an evolutionary intermediate in type III effectors 8,9 , in pre- and post-cleavage states, which show metal ion coordination in the active sites. Using structural, biochemical, and quantum/classical molecular dynamics simulation, we reveal the structure and dynamics of the three catalytic sites, where a 2'-OH of the ribose on the target RNA acts as a nucleophile for in line self-cleavage of the upstream scissile phosphate. Strikingly, the arrangement at the catalytic residues of most type III complexes resembles the active site of ribozymes, including the hammerhead, pistol, and Varkud satellite ribozymes. Thus, type III CRISPR-Cas complexes function as protein-assisted ribozymes, and their programmable nature has important implications for how these complexes could be repurposed for applications. Competing Interests: Competing interests E.A.S., J.P.K.B., P.C.F., R.D.F., and D.W.T. are inventors on a filed patent based on this work.
Databáze:	MEDLINE
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