Bacterial virus anti-defence systems · sequence & structure resource

Encyclopaedia of Bacterial Virus Anti-Defence Systems


Protein: ORF55

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Overview

Mode of Action (MoA) predicted to act as a nick-sensing, ATP-dependent DNA ligase (ipTM = 0.95, pTM = 0.95) that reverses the effect of effector nucleases.
Evidence ORF55 was identified via a knockout screen where its deletion led to >100-fold reduction in infectivity against E. coli expressing AVAST type III, accompanied by small plaque formation. Complementation of the ΔORF55 mutant with a plasmid-borne ORF55 restored infectivity and plaque size, confirming its anti-AVAST function. Binding nicked DNA and ATP is supported by computational structure modeling evidence (ECO_0006368).
MoA Category synthesises and restores essential molecules depleted by bacterial defence (putative)
Subtype(s) of the defence system(s) inhibited by the protein Defence Subtype Escherichia coli type III Avs
Relevant publication(s) DOI 10.1101/2024.04.14.589459
Other components of the anti-defence system Multicomponent System -
Known structure in PDB PDB ID -
Genome(s) encoding the protein Protein Source DruSM1 phage
Defence system(s) inhibited by the protein Defences Avs
View homologs from eukaryotic dsDNA viruses

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
DNA_ligase_OB_2 PF14743 66 7 66 230 296 226 296 2.9e-09

Sequence Viewer

Amino acid position: -

MAFKPHLATDAVEEKIKFPCCILPKIDGVRGLNPDGRIVGRSLKLFKNRHTSAIFSGPQYMGYDGELAAGVETDPDLCRKTTSAVNTIEGEPFLKWHIFDLCAESVAELGYEARYNMMKDFITTQHAKGELLDLQVVPMYVVKSLQELLYWENIWLDMGYEGIIIRDPEKPYKHGRGTVREGGYLRIKRFIQEDAIVLDIIEGETNLNEATVNELGRTTRSSHQENKVPNGMIGTLVCKDVKTGNTINVSPGKLTQEDKIYYWNNPDKIKGRTISYKHFPHGVKDKPRFANFMHFRDESDQALD