7XI5

Anti-CRISPR-associated Aca10

Summary for 7XI5

• Entry DOI: 10.2210/pdb7xi5/pdb
• Descriptor: Transcriptional regulator (2 entities in total)
• Functional Keywords: aca10, immune system, dna binding protein, autoregulator
• Biological source: Pseudomonas citronellolis
• Total number of polymer chains: 4
• Total formula weight: 28432.32

Authors

Lee, S.Y.,Park, H.H. (deposition date: 2022-04-12, release date: 2023-02-22, Last modification date: 2023-11-29)

Primary citation

Lee, S.Y.,Birkholz, N.,Fineran, P.C.,Park, H.H.
Molecular basis of anti-CRISPR operon repression by Aca10.
Nucleic Acids Res., 50:8919-8928, 2022

PubMed Abstract: CRISPR-Cas systems are bacterial defense systems for fighting against invaders such as bacteriophages and mobile genetic elements. To escape destruction by these bacterial immune systems, phages have co-evolved multiple anti-CRISPR (Acr) proteins, which inhibit CRISPR-Cas function. Many acr genes form an operon with genes encoding transcriptional regulators, called anti-CRISPR-associated (Aca) proteins. Aca10 is the most recently discovered Aca family that is encoded within an operon containing acrIC7 and acrIC6 in Pseudomonas citronellolis. Here, we report the high-resolution crystal structure of an Aca10 protein to unveil the molecular basis of transcriptional repressor role of Aca10 in the acrIC7-acrIC6-aca10 operon. We identified that Aca10 forms a dimer in solution, which is critical for binding specific DNA. We also showed that Aca10 directly recognizes a 21 bp palindromic sequence in the promoter of the acr operon. Finally, we revealed that R44 of Aca10 is a critical residue involved in the DNA binding, which likely results in a high degree of DNA bending.

PubMed: 35920325
DOI: 10.1093/nar/gkac656

Experimental method

X-RAY DIFFRACTION (1.76 Å)