Bacterial virus anti-defence systems · sequence & structure resource

Encyclopaedia of Bacterial Virus Anti-Defence Systems


Protein: ArdU

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Overview

Mode of Action (MoA) shares high similarity to ArdA (PDB ID: 2w82), which binds to the MTase of the type I RM complex and blocks it. AlphaFold 3 predicts a moderate-confidence complex between MTase (https://www.ncbi.nlm.nih.gov/protein/WP_010883983.1) and ArdU (ipTM = 0.76, pTM = 0.76).
Evidence ArdU was identified as a putative antirestriction protein based on sequence similarity to known antirestriction proteins such as ArdA from Yersinia pestis plasmid pMT-1, and others from enterobacterial plasmids like pKM101 and ColIb-P9. It was predicted to be highly acidic (pI 4.25), a characteristic feature of known Ard proteins. To test its functional role, the ardU gene was removed from plasmid pI3, resulting in derivative pI5. Transformation assays in Deinococcus radiodurans R1 showed that deletion of ardU led to a 50- to 100-fold decrease in transformation frequency compared to wild-type pI3, indicating that ArdU enhances transformation efficiency. However, ArdU was not required for replication or stable maintenance of the plasmid. These results support a role for ArdU in overcoming host restriction barriers during plasmid uptake, consistent with antirestriction function. Binding it supported by computational structure modeling evidence (ECO_0006368).
MoA Category binds and inhibits host defence system (putative)
Subtype(s) of the defence system(s) inhibited by the protein Defence Subtype Deinococcus radiodurans RM systems
Relevant publication(s) DOI 10.1128/AEM.66.9.3856-3867.2000
Other components of the anti-defence system Multicomponent System -
Known structure in PDB PDB ID -
Genome(s) encoding the protein Protein Source Deinococcus radiopugnans plasmid pUE30
Defence system(s) inhibited by the protein Defences RM

3D structure

AlphaFold 3 model.

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Feature viewer - predicted secondary structure

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Pfam annotations

Pfam Name Pfam Acc Pfam Length Colour HMM Start HMM End Ali Start Ali End Env Start Env End Evalue
ArdA PF07275 155 2 154 19 178 18 179 3.1e-32

Sequence Viewer

Amino acid position: -

MTYTHPLIIERHPDAPALWIGCLAAYNAGKLHGAWMQASSDTAEMFGAIEEILKASPEPHAEEWDIMDTDNMPTEAGRTLDSAATYVAALDALSRADAAEIVAAWVEWRGAEEMDADKITDAYLGRFDSVEDYAAQYLDDSGALQEVPEWLRPYINTAALGRDMEINGDVYEGKNGHFFNGHA