SNAP output for PDB entry 5uz9 [SNAP web server]

PDB-id

5uz9; SNAP-derived features in text and JSON formats; DNAproDB

Class

immune system-RNA

Method

cryo-EM (3.4 Å)

Summary

Cryo em structure of anti-crisprs, acrf1 and acrf2, bound to type i-f crrna-guided crispr surveillance complex

Reference

Chowdhury S, Carter J, Rollins MF, Golden SM, Jackson RN, Hoffmann C, Nosaka L, Bondy-Denomy J, Maxwell KL, Davidson AR, Fischer ER, Lander GC, Wiedenheft B (2017): "Structure Reveals Mechanisms of Viral Suppressors that Intercept a CRISPR RNA-Guided Surveillance Complex." Cell, 169, 47-57.e11. doi: 10.1016/j.cell.2017.03.012.

Abstract

Genetic conflict between viruses and their hosts drives evolution and genetic innovation. Prokaryotes evolved CRISPR-mediated adaptive immune systems for protection from viral infection, and viruses have evolved diverse anti-CRISPR (Acr) proteins that subvert these immune systems. The adaptive immune system in Pseudomonas aeruginosa (type I-F) relies on a 350 kDa CRISPR RNA (crRNA)-guided surveillance complex (Csy complex) to bind foreign DNA and recruit a trans-acting nuclease for target degradation. Here, we report the cryo-electron microscopy (cryo-EM) structure of the Csy complex bound to two different Acr proteins, AcrF1 and AcrF2, at an average resolution of 3.4 Å. The structure explains the molecular mechanism for immune system suppression, and structure-guided mutations show that the Acr proteins bind to residues essential for crRNA-mediated detection of DNA. Collectively, these data provide a snapshot of an ongoing molecular arms race between viral suppressors and the immune system they target.