Bacterial virus anti-defence systems · sequence & structure resource

Encyclopaedia of Bacterial Virus Anti-Defence Systems


Protein: OrbA

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Overview

Mode of Action (MoA) directly binds the ATPase BrxC, disrupting its dimerisation
Evidence Deletion (ECO_0001038) of orbA abolished plaque formation and phage genome replication in Vibrio cholerae strains expressing the BREX system from ICEVchInd5. This restriction was relieved either by restoring orbA or deleting the brxC component of BREX, confirming OrbA’s role in counter-defense. Co-immunoprecipitation (ECO_0005644) experiments revealed that OrbA binds directly to BrxC, the ATPase component of BREX. A bacterial two-hybrid assay (ECO_0005805) confirmed this interaction occurs specifically with the Ind5 BrxC variant, which OrbA inhibits, but not with BrxC from BREX systems that resist OrbA. Furthermore, OrbA expression disrupted BrxC multimerization in vivo, a process dependent on intact Walker A and B ATPase motifs, suggesting OrbA inhibits BREX by interfering with BrxC oligomerization and function.
MoA Category binds and inhibits host defence system
Subtype(s) of the defence system(s) inhibited by the protein Defence Subtype Vibrio cholerae type I BREX
Relevant publication(s) DOI 10.1126/science.abg2166, 10.1128/jb.00206-24
Other components of the anti-defence system Multicomponent System -
Known structure in PDB PDB ID -
Genome(s) encoding the protein Protein Source Vibrio phage ICP1
Defence system(s) inhibited by the protein Defences BREX

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: -

MKIANNYTFKQNKDGSVTVYNHGMFCAIIDEGMSRAKRIFLETV