6RJA

Cryo-EM structure of St1Cas9-sgRNA-tDNA20-AcrIIA6 dimeric assembly.

Summary for 6RJA

• Entry DOI: 10.2210/pdb6rja/pdb
• Related: 6RJ9 6RJD 6RJG
• EMDB information: 4900 4901 4902 4904
• Descriptor: AcrIIA6, CRISPR-associated endonuclease Cas9 1, RNA (78-MER), ... (4 entities in total)
• Functional Keywords: crispr-cas9, anti-crispr protein, bacteriophages, streptococcus thermophilus cas9, st1cas9, hydrolase
• Biological source: Streptococcus phage D1811; More
• Total number of polymer chains: 8
• Total formula weight: 389408.77

Authors

Goulet, A.,Cambillau, C.,Chaves-Sanjuan, A. (deposition date: 2019-04-26, release date: 2019-10-02, Last modification date: 2024-05-22)

Primary citation

Fuchsbauer, O.,Swuec, P.,Zimberger, C.,Amigues, B.,Levesque, S.,Agudelo, D.,Duringer, A.,Chaves-Sanjuan, A.,Spinelli, S.,Rousseau, G.M.,Velimirovic, M.,Bolognesi, M.,Roussel, A.,Cambillau, C.,Moineau, S.,Doyon, Y.,Goulet, A.
Cas9 Allosteric Inhibition by the Anti-CRISPR Protein AcrIIA6.
Mol.Cell, 76:922-, 2019

PubMed Abstract: In the arms race against bacteria, bacteriophages have evolved diverse anti-CRISPR proteins (Acrs) that block CRISPR-Cas immunity. Acrs play key roles in the molecular coevolution of bacteria with their predators, use a variety of mechanisms of action, and provide tools to regulate Cas-based genome manipulation. Here, we present structural and functional analyses of AcrIIA6, an Acr from virulent phages, exploring its unique anti-CRISPR action. Our cryo-EM structures and functional data of AcrIIA6 binding to Streptococcus thermophilus Cas9 (St1Cas9) show that AcrIIA6 acts as an allosteric inhibitor and induces St1Cas9 dimerization. AcrIIA6 reduces St1Cas9 binding affinity for DNA and prevents DNA binding within cells. The PAM and AcrIIA6 recognition sites are structurally close and allosterically linked. Mechanistically, AcrIIA6 affects the St1Cas9 conformational dynamics associated with PAM binding. Finally, we identify a natural St1Cas9 variant resistant to AcrIIA6 illustrating Acr-driven mutational escape and molecular diversification of Cas9 proteins.

PubMed: 31604602
DOI: 10.1016/j.molcel.2019.09.012

Experimental method

ELECTRON MICROSCOPY (3 Å)