7svu | pdb_00007svu

TnsBctd-TnsC-TniQ complex

spinqualitylabelsall models 7svu, resolution 3.50Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 7svu is a 24 chain structure with sequence from Scytonema hofmanni UTEX 2349 and Synthetic construct. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: Electron Microscopy, Resolution 3.5Å Ligands: ATP, MG Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function A0A8J0PCL5_9CYAN Publication Abstract from PubMed CRISPR-associated transposons (CAST) are programmable mobile genetic elements that insert large DNA cargos using an RNA-guided mechanism(1-3). CAST elements contain multiple conserved proteins: a CRISPR effector (Cas12k or Cascade), a AAA+ regulator (TnsC), a transposase (TnsA-TnsB) and a target-site-associated factor (TniQ). These components are thought to cooperatively integrate DNA via formation of a multisubunit transposition integration complex (transpososome). Here we reconstituted the approximately 1 MDa type V-K CAST transpososome from Scytonema hofmannii (ShCAST) and determined its structure using single-particle cryo-electon microscopy. The architecture of this transpososome reveals modular association between the components. Cas12k forms a complex with ribosomal subunit S15 and TniQ, stabilizing formation of a full R-loop. TnsC has dedicated interaction interfaces with TniQ and TnsB. Of note, we observe TnsC-TnsB interactions at the C-terminal face of TnsC, which contribute to the stimulation of ATPase activity. Although the TnsC oligomeric assembly deviates slightly from the helical configuration found in isolation, the TnsC-bound target DNA conformation differs markedly in the transpososome. As a consequence, TnsC makes new protein-DNA interactions throughout the transpososome that are important for transposition activity. Finally, we identify two distinct transpososome populations that differ in their DNA contacts near TniQ. This suggests that associations with the CRISPR effector can be flexible. This ShCAST transpososome structure enhances our understanding of CAST transposition systems and suggests ways to improve CAST transposition for precision genome-editing applications. Structures of the holo CRISPR RNA-guided transposon integration complex.,Park JU, Tsai AW, Rizo AN, Truong VH, Wellner TX, Schargel RD, Kellogg EH Nature. 2023 Jan;613(7945):775-782. doi: 10.1038/s41586-022-05573-5. Epub 2022 , Nov 28. PMID:36442503 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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