6AS3

Structure of a phage anti-CRISPR protein

Summary for 6AS3

• Entry DOI: 10.2210/pdb6as3/pdb
• Descriptor: NHis AcrE1 protein (2 entities in total)
• Functional Keywords: phage protein, unknown function
• Biological source: Pseudomonas phage JBD5
• Total number of polymer chains: 4
• Total formula weight: 48586.35

Authors

Shah, M.,Calmettes, C.,Pawluk, A.,Mejdani, M.,Davidson, A.R.,Maxwell, K.L.,Moraes, T.F. (deposition date: 2017-08-23, release date: 2018-08-29, Last modification date: 2023-10-04)

Primary citation

Pawluk, A.,Shah, M.,Mejdani, M.,Calmettes, C.,Moraes, T.F.,Davidson, A.R.,Maxwell, K.L.
Disabling a Type I-E CRISPR-Cas Nuclease with a Bacteriophage-Encoded Anti-CRISPR Protein.
MBio, 8:-, 2017

PubMed Abstract: CRISPR (clustered regularly interspaced short palindromic repeat)-Cas adaptive immune systems are prevalent defense mechanisms in bacteria and archaea. They provide sequence-specific detection and neutralization of foreign nucleic acids such as bacteriophages and plasmids. One mechanism by which phages and other mobile genetic elements are able to overcome the CRISPR-Cas system is through the expression of anti-CRISPR proteins. Over 20 different families of anti-CRISPR proteins have been described, each of which inhibits a particular type of CRISPR-Cas system. In this work, we determined the structure of type I-E anti-CRISPR protein AcrE1 by X-ray crystallography. We show that AcrE1 binds to the CRISPR-associated helicase/nuclease Cas3 and that the C-terminal region of the anti-CRISPR protein is important for its inhibitory activity. We further show that AcrE1 can convert the endogenous type I-E CRISPR system into a programmable transcriptional repressor. The CRISPR-Cas immune system provides bacteria with resistance to invasion by potentially harmful viruses, plasmids, and other foreign mobile genetic elements. This study presents the first structural and mechanistic insight into a phage-encoded protein that inactivates the type I-E CRISPR-Cas system in The interaction of this anti-CRISPR protein with the CRISPR-associated helicase/nuclease proteins Cas3 shuts down the CRISPR-Cas system and protects phages carrying this gene from destruction. This interaction also allows the repurposing of the endogenous type I-E CRISPR system into a programmable transcriptional repressor, providing a new biotechnological tool for genetic studies of bacteria encoding this type I-E CRISPR-Cas system.

PubMed: 29233895
DOI: 10.1128/mBio.01751-17

Experimental method

X-RAY DIFFRACTION (2 Å)