Structural insights into Cas9-mediated prespacer selection in CRISPR-Cas adaptation - PubMed
4 days ago
- #Cryo-EM
- #Cas9
- #CRISPR
- Prokaryotic cells insert foreign DNA fragments (spacers) into their genome for RNA-guided immunity during CRISPR-Cas adaptation.
- Spacer acquisition involves the Cas1-Cas2 integrase and accessory proteins, selecting DNA sequences near the protospacer adjacent motif (PAM).
- In type II-A systems, Cas9 mediates prespacer selection by forming a supercomplex with Cas1-Cas2 and Csn2.
- Cryo-EM structures of the Streptococcus thermophilus prespacer selection supercomplex reveal DNA-scanning and PAM-bound configurations.
- The study highlights Cas9's plasticity and expands understanding of its role in CRISPR-Cas systems.