Bacterial virus anti-defence systems · sequence & structure resource

Encyclopaedia of Bacterial Virus Anti-Defence Systems


Protein: AcrIIA31

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Overview

Mode of Action (MoA) AlphaFold 3 predicts a direct interaction between Cas9 (https://www.ncbi.nlm.nih.gov/protein/CAD0136979.1) and AcrIIA31 (ipTM = 0.87, pTM = 0.62).
Evidence Binding it supported by computational structure modeling evidence (ECO_0006368).AcrIIA31 was found in a mobile element from Streptococcus sp. and validated as a strong and specific inhibitor of St1Cas9. In plasmid interference assays, E. coli expressing St1Cas9 and a targeting sgRNA failed to maintain the targeted plasmid, leading to growth inhibition. Co-expression of AcrIIA31 rescued colony formation, confirming its inhibitory activity. In vitro DNA cleavage assays and EMSAs demonstrated that AcrIIA31 blocked Cas9–DNA interactions but did not interfere with sgRNA loading.
MoA Category binds and inhibits host defence system (putative)
Subtype(s) of the defence system(s) inhibited by the protein Defence Subtype Streptococcus thermophilus type II-A CRISPR-Cas
Relevant publication(s) DOI 10.1093/nar/gkac099
Other components of the anti-defence system Multicomponent System -
Known structure in PDB PDB ID -
Genome(s) encoding the protein Protein Source MGE in Streptococcus sp. SR1
Defence system(s) inhibited by the protein Defences CRISPR-Cas

3D structure

AlphaFold 3 model.

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Feature viewer - predicted secondary structure

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Pfam annotations

No Pfam domains found

Sequence Viewer

Amino acid position: -

MVTEEQLKEVLVGIYETEYKDEQTFEEYADGWDFWIDKDGDILIEGRGMKPIDGVQKVGHVDNGVIYAY