Structural highlights
Publication Abstract from PubMedType IV CRISPR-Cas systems, which are primarily found on plasmids and exhibit a strong plasmid-targeting preference, are the only one of the six known CRISPR-Cas types for which the mechanistic details of their function remain unknown. Here, we provide high-resolution functional snapshots of type IV-A Csf complexes before and after target dsDNA binding, either in the absence or presence of CasDinG, revealing the mechanisms underlying Csf(crRNA) complex assembly, "DWN" PAM-dependent dsDNA targeting, R-loop formation, and CasDinG recruitment. Furthermore, we establish that CasDinG, a signature DinG family helicase, harbors ssDNA-stimulated ATPase activity and ATP-dependent 5'-3' DNA helicase activity. In addition, we show that CasDinG unwinds the non-target strand (NTS) and target strand (TS) of target dsDNA from the Csf(crRNA) complex. These molecular details advance our mechanistic understanding of type IV-A CRISPR-Csf function and should enable Csf complexes to be harnessed as genome-engineering tools for biotechnological applications. Type IV-A CRISPR-Csf complex: Assembly, dsDNA targeting, and CasDinG recruitment.,Cui N, Zhang JT, Liu Y, Liu Y, Liu XY, Wang C, Huang H, Jia N Mol Cell. 2023 Jul 20;83(14):2493-2508.e5. doi: 10.1016/j.molcel.2023.05.036. , Epub 2023 Jun 20. PMID:37343553[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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