7B5J

Anti-CRISPR associated (Aca) protein, Aca2

Summary for 7B5J

• Entry DOI: 10.2210/pdb7b5j/pdb
• Descriptor: Anti-CRISPR associated (Aca) protein, Aca2, GLYCEROL (3 entities in total)
• Functional Keywords: rna-binding, dna-binding, anti-crispr, regulator, rna binding protein, anti-crispr associated (aca) protein, dna binding protein
• Biological source: Pectobacterium phage ZF40
• Total number of polymer chains: 2
• Total formula weight: 26511.80

Authors

Usher, B.,Birkholz, N.,Fineran, P.C.,Blower, T.R. (deposition date: 2020-12-03, release date: 2021-06-23, Last modification date: 2024-06-19)

Primary citation

Usher, B.,Birkholz, N.,Beck, I.N.,Fagerlund, R.D.,Jackson, S.A.,Fineran, P.C.,Blower, T.R.
Crystal structure of the anti-CRISPR repressor Aca2.
J.Struct.Biol., 213:107752-107752, 2021

PubMed Abstract: Bacteria use adaptive CRISPR-Cas immune mechanisms to protect from invasion by bacteriophages and other mobile genetic elements. In response, bacteriophages and mobile genetic elements have co-evolved anti-CRISPR proteins to inhibit the bacterial defense. We and others have previously shown that anti-CRISPR associated (Aca) proteins can regulate this anti-CRISPR counter-attack. Here, we report the first structure of an Aca protein, the Aca2 DNA-binding transcriptional autorepressor from Pectobacterium carotovorum bacteriophage ZF40, determined to 1.34 Å. Aca2 presents a conserved N-terminal helix-turn-helix DNA-binding domain and a previously uncharacterized C-terminal dimerization domain. Dimerization positions the Aca2 recognition helices for insertion into the major grooves of target DNA, supporting its role in regulating anti-CRISPRs. Furthermore, database comparisons identified uncharacterized Aca2 structural homologs in pathogenic bacteria, suggesting that Aca2 represents the first characterized member of a more widespread family of transcriptional regulators.

PubMed: 34116143
DOI: 10.1016/j.jsb.2021.107752

Experimental method

X-RAY DIFFRACTION (1.34 Å)