7FIA | pdb_00007fia

Structure of AcrIF23

• PDB DOI: https://doi.org/10.2210/pdb7FIA/pdb

• Classification: VIRAL PROTEIN
• Organism(s): Pseudomonas aeruginosa
• Expression System: Escherichia coli
• Mutation(s): No 


• Deposited: 2021-07-30 Released: 2022-07-27 
• Deposition Author(s): Ren, J., Yue, F.
• Funding Organization(s): National Science Foundation (NSF, China)

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 2.13 Å
• R-Value Free: 
  0.231 (Depositor), 0.233 (DCC) 
• R-Value Work: 
  0.205 (Depositor), 0.206 (DCC) 
• R-Value Observed: 
  0.206 (Depositor) 

Literature

Structural and mechanistic insights into the inhibition of type I-F CRISPR-Cas system by anti-CRISPR protein AcrIF23.

Ren, J., Wang, H., Yang, L., Li, F., Wu, Y., Luo, Z., Chen, Z., Zhang, Y., Feng, Y.

(2022) J Biological Chem 298: 102124-102124

• PubMed: 35697070 
• DOI: https://doi.org/10.1016/j.jbc.2022.102124
• Primary Citation Related Structures: 
  7FIA


• PubMed Abstract: 
  

  Prokaryotes evolved clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated (Cas) proteins as a kind of adaptive immune defense against mobile genetic elements including harmful phages. To counteract this defense, many mobile genetic elements in turn encode anti-CRISPR proteins (Acrs) to inactivate the CRISPR-Cas system. While multiple mechanisms of Acrs have been uncovered, it remains unknown whether other mechanisms are utilized by uncharacterized Acrs. Here, we report a novel mechanism adopted by recently identified AcrIF23. We show that AcrIF23 interacts with the Cas2/3 helicase-nuclease in the type I-F CRISPR-Cas system, similar to AcrIF3. The structure of AcrIF23 demonstrated a novel fold and structure-based mutagenesis identified a surface region of AcrIF23 involved in both Cas2/3-binding and its inhibition capacity. Unlike AcrIF3, however, we found AcrIF23 only potently inhibits the DNA cleavage activity of Cas2/3 but does not hinder the recruitment of Cas2/3 to the CRISPR RNA-guided surveillance complex (the Csy complex). Also, in contrast to AcrIF3 which hinders substrate DNA recognition by Cas2/3, we show AcrIF23 promotes DNA binding to Cas2/3. Taken together, our study identifies a novel anti-CRISPR mechanism used by AcrIF23 and highlights the diverse mechanisms adopted by Acrs.

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Organizational Affiliation: 
• Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing Key Laboratory of Bioprocess, State Key Laboratory of Chemical Resource Engineering, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, China.
Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing Key Laboratory of Bioprocess, State Key Laboratory of Chemical Resource Engineering, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, China; Jiangxi Provincial Key Laboratory of Natural Active Pharmaceutical Constituents, Department of Chemistry and Bioengineering, Yichun University, Yichun, China.
State Key Laboratory of Plant Genomic, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.
Institute of Molecular Enzymology, School of Biology and Basic Medical Sciences, Soochow University, Suzhou, Jiangsu, China.
Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing Key Laboratory of Bioprocess, State Key Laboratory of Chemical Resource Engineering, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, China; Key Laboratory of Livestock Infectious Diseases in Northeast China, Ministry of Education, College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, Shenyang, Liaoning Province, China. Electronic address: [e-mail].
Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing Key Laboratory of Bioprocess, State Key Laboratory of Chemical Resource Engineering, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, China. Electronic address: [e-mail].
Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing Key Laboratory of Bioprocess, State Key Laboratory of Chemical Resource Engineering, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, China. Electronic address: [e-mail].

Biological Assembly 1  

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Monomer - A1 

Biological assembly 1 assigned by authors.

Biological Assembly Evidence: gel filtration

Macromolecule Content 

• Total Structure Weight: 17.72 kDa 
• Atom Count: 1,374 
• Modeled Residue Count: 160 
• Deposited Residue Count: 161 
• Unique protein chains: 1

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
AcrIF23	A	161	Pseudomonas aeruginosa	Mutation(s): 0

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 2.13 Å
• R-Value Free:  0.231 (Depositor), 0.233 (DCC) 
• R-Value Work:  0.205 (Depositor), 0.206 (DCC) 
• R-Value Observed: 0.206 (Depositor) 

Space Group: P 4₁ 2₁ 2

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 65.569	α = 90
b = 65.569	β = 90
c = 95.053	γ = 90

Software Package:

Software Name	Purpose
PHENIX	refinement
PDB_EXTRACT	data extraction
HKL-3000	data reduction
SCALEPACK	data scaling
AutoSol	phasing

Structure Validation

Entry History 

& Funding Information

Deposition Data

• Released Date: 2022-07-27 
Deposition Author(s): Ren, J., Yue, F.

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Funding Organization	Location	Grant Number
National Science Foundation (NSF, China)	China	31822012

Revision History  

• Version 1.0: 2022-07-27
  Type: Initial release
  
• Version 1.1: 2024-05-29
  Changes: Data collection