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Review
. 2021 Nov 12;18(sup2):562-573.
doi: 10.1080/15476286.2021.1985347. Epub 2021 Oct 4.

Structural insights into the inactivation of the type I-F CRISPR-Cas system by anti-CRISPR proteins

Lingguang Yang  1   2 , Yi Zhang  1 , Peipei Yin  1   2 , Yue Feng  1
Affiliations
Review

Structural insights into the inactivation of the type I-F CRISPR-Cas system by anti-CRISPR proteins

Lingguang Yang et al. RNA Biol. .

Abstract

Phage infection is one of the major threats to prokaryotic survival, and prokaryotes in turn have evolved multiple protection approaches to fight against this challenge. Various delicate mechanisms have been discovered from this eternal arms race, among which the CRISPR-Cas systems are the prokaryotic adaptive immune systems and phages evolve diverse anti-CRISPR (Acr) proteins to evade this immunity. Until now, about 90 families of Acr proteins have been identified, out of which 24 families were verified to fight against subtype I-F CRISPR-Cas systems. Here, we review the structural and biochemical mechanisms of the characterized type I-F Acr proteins, classify their inhibition mechanisms into two major groups and provide insights for future studies of other Acr proteins. Understanding Acr proteins in this context will lead to a variety of practical applications in genome editing and also provide exciting insights into the molecular arms race between prokaryotes and phages.

Keywords: CRISPR-Cas systems; adaptive immune system; anti-CRISPR; structure; type I-F system.

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Conflict of interest statement

No potential conflict of interest was reported by the author(s).

Figures

Figure 1.
Figure 1.
Working mechanisms of type I-F CRISPR-Cas system
Figure 2.
Figure 2.
Overall structures of Csy and Csy-dsDNA complexes
Figure 3.
Figure 3.
Overall structures of Csy complexed with AcrIF1, AcrIF9 and AcrIF14
Figure 4.
Figure 4.
Overall structures of Csy complexed with AcrIF2, AcrIF6, AcrIF7, AcrIF8 and AcrIF10
Figure 5.
Figure 5.
Overall structure of AcrIF11 and its alignment with diphtheria toxin
Figure 6.
Figure 6.
Overall structures of the Cas2/3-AcrIF3 complex and AcrIF3
Figure 7.
Figure 7.
Overall structure of the Csy-AcrIF4 complex
Figure 8.
Figure 8.
A summary of the inhibition mechanisms of the 11 AcrIF proteins reviewed in this study
Figure 9.
Figure 9.
A plot of the 24 type I-F Acr proteins with their molecular weight and theoretical pI values
See this image and copyright information in PMC

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