9VZX

Cryo-EM structure of TasH-tigRNA-gap dsDNA complex

Summary for 9VZX

• Entry DOI: 10.2210/pdb9vzx/pdb
• EMDB information: 65487
• Descriptor: HNH nuclease domain-containing protein, RNA (36-MER), DNA (38-MER), ... (4 entities in total)
• Functional Keywords: protein complex, antiviral protein
• Biological source: Salicola phage CGphi29; More
• Total number of polymer chains: 5
• Total formula weight: 115397.80

Authors

Zhang, H.,Liu, Z. (deposition date: 2025-07-23, release date: 2026-03-11, Last modification date: 2026-04-22)

Primary citation

Yang, J.,Wang, T.,Liu, Z.,Wu, W.,Sun, Y.,Zhan, Y.,Zhang, S.,Chen, H.,Liu, B.,Yue, C.,Yin, Z.,Shan, Z.,Li, X.,Li, Z.,Yuan, Z.,Yin, H.,Zhang, H.
Molecular basis for dual-spacer-guided target cleavage by the TIGR-TasH system.
Mol.Cell, 86:1217-1229.e6, 2026

PubMed Abstract: The RNA-directed programmable nuclease systems, exemplified by the CRISPR-Cas system, have been widely used in genome editing. In contrast to the single-spacer configuration of CRISPR RNA (crRNA), the guide RNA (tigRNA) of the tandem interspaced guide RNA (TIGR) system features a dual-spacer arrangement, thereby directing the TIGR-associated (Tas) protein to engage both strands of the target double-stranded DNA (dsDNA). Here, we determine six cryo-electron microscopy structures of the Salicola phage TIGR-TasH complex. The central coiled-coil region of TasH mediates dimerization, while the C-terminal nucleolar protein (Nop) domain is able to autonomously process precursor tigRNA. Upon target binding, the dynamic N-terminal HNH nuclease domain is recruited for cleavage through a β-hairpin, which also determines the target preference. More interestingly, the conserved box C motif of tigRNA stabilizes this β-hairpin in an adenine-specific manner, enabling us to rationally design a guide RNA-defined nickase, distinct from conventional protein-based nickase strategies used in genome editing.

PubMed: 41831437
DOI: 10.1016/j.molcel.2026.02.017

Experimental method

ELECTRON MICROSCOPY (2.78 Å)