7WE6

Structure of Csy-AcrIF24-dsDNA

Summary for 7WE6

• Entry DOI: 10.2210/pdb7we6/pdb
• EMDB information: 32440
• Descriptor: CRISPR type I-F/YPEST-associated protein Csy2, CRISPR-associated protein Csy3, Type I-F CRISPR-associated endoribonuclease Cas6/Csy4, ... (8 entities in total)
• Functional Keywords: complex, inhibitor, immune system, immune system-rna complex, viral protein
• Biological source: Pseudomonas aeruginosa; More
• Total number of polymer chains: 26
• Total formula weight: 820541.35

Authors

Zhang, L.,Feng, Y. (deposition date: 2021-12-22, release date: 2022-04-20, Last modification date: 2024-06-26)

Primary citation

Yang, L.,Zhang, L.,Yin, P.,Ding, H.,Xiao, Y.,Zeng, J.,Wang, W.,Zhou, H.,Wang, Q.,Zhang, Y.,Chen, Z.,Yang, M.,Feng, Y.
Insights into the inhibition of type I-F CRISPR-Cas system by a multifunctional anti-CRISPR protein AcrIF24.
Nat Commun, 13:1931-1931, 2022

PubMed Abstract: CRISPR-Cas systems are prokaryotic adaptive immune systems and phages use anti-CRISPR proteins (Acrs) to counteract these systems. Here, we report the structures of AcrIF24 and its complex with the crRNA-guided surveillance (Csy) complex. The HTH motif of AcrIF24 can bind the Acr promoter region and repress its transcription, suggesting its role as an Aca gene in self-regulation. AcrIF24 forms a homodimer and further induces dimerization of the Csy complex. Apart from blocking the hybridization of target DNA to the crRNA, AcrIF24 also induces the binding of non-sequence-specific dsDNA to the Csy complex, similar to AcrIF9, although this binding seems to play a minor role in AcrIF24 inhibitory capacity. Further structural and biochemical studies of the Csy-AcrIF24-dsDNA complexes and of AcrIF24 mutants reveal that the HTH motif of AcrIF24 and the PAM recognition loop of the Csy complex are structural elements essential for this non-specific dsDNA binding. Moreover, AcrIF24 and AcrIF9 display distinct characteristics in inducing non-specific DNA binding. Together, our findings highlight a multifunctional Acr and suggest potential wide distribution of Acr-induced non-specific DNA binding.

PubMed: 35411005
DOI: 10.1038/s41467-022-29581-1

Experimental method

ELECTRON MICROSCOPY (3.2 Å)