Molecular basis for dual-spacer-guided target cleavage by the TIGR-TasH system - PubMed
3 hours ago
- #cryo-EM
- #TIGR-TasH
- #genome editing
- The TIGR-TasH system uses a dual-spacer guide RNA (tigRNA) to target both strands of dsDNA, unlike the single-spacer CRISPR-Cas system.
- Six cryo-EM structures of the Salicola phage TIGR-TasH complex reveal TasH dimerization via a central coiled-coil region and precursor tigRNA processing by the C-terminal Nop domain.
- Target binding recruits the N-terminal HNH nuclease domain for cleavage, with specificity determined by a β-hairpin.
- The conserved box C motif in tigRNA stabilizes the β-hairpin in an adenine-specific manner, enabling the design of a guide RNA-defined nickase.
- This system offers a novel approach to genome editing, distinct from protein-based nickase strategies.