P0DUF9 · PGLX_ECOHS

Function

function

BREX systems (bacteriophage exclusion) provide immunity against bacteriophage. Part of a type 1 BREX system which protects against dsDNA phage. This system allows phage adsorption but prevents phage DNA replication, without degradation of the phage DNA. Methylation of bacterial DNA by this protein guides self/non-self discrimination. When the brxA-brxB-brxC-pglX-pglZ-brxL genes are transformed into a susceptible E.coli strain (BW25113) they confer very high resistance to infection by bacteriophage VR7 and VpaE1, about 100-fold protection against lambda, T5 and T7 (probably with a mutated 0.3 gene) and no protection against RNA phage Qbeta, ssDNA phage M13 or dSDNA phage T4 and VR5. Glycosylated phage DNA is not susceptible to BREX. The BREX system does not confer resistance to lysogenic lambda phage, i.e. prophage that are integrated into the chromosomal DNA and then induced to form phage.
Methylates the adenine in the fifth position of the hexamer 5'-GGTAAG-3' in genomic DNA; methylates the same sequence in the few phage that escape the BREX system. Methylated phage are now resistant to BREX, showing immunity is provided by an epigenetic modification. Expression of this protein alone has no effect on phage infection, does not lead to methylated DNA and mildly inhibits growth.

Catalytic activity

Activity regulation

Methyltransferase activity is partially inhibited (20% reduction) by phage T7 protein OCR (AC P03775, gene 0.3). Viability of cells overexpressing OCR is unaffected.

GO annotations

AspectTerm
Molecular Functionnucleic acid binding
Molecular Functionsite-specific DNA-methyltransferase (adenine-specific) activity
Biological Processdefense response to virus
Biological ProcessDNA modification
Biological Processmethylation

Keywords

Enzyme and pathway databases

Protein family/group databases

Names & Taxonomy

Protein names

  • Recommended name
    Adenine-specific methyltransferase BrxX
  • EC number
  • Alternative names
    • BREX protein PglX

Gene names

    • Name
      pglX
    • Synonyms
      brxX
    • Ordered locus names
      EcHS_A0339

Organism names

Accessions

  • Primary accession
    P0DUF9
  • Secondary accessions
    • A0A7M3S2P4

Proteomes

Phenotypes & Variants

Disruption phenotype

No methylation of 5'-GGTAAG-3' in chromosomal DNA, BREX no longer confers phage resistance.

PTM/Processing

Features

Showing features for chain.

TypeIDPosition(s)Description
ChainPRO_00004521631-1205Adenine-specific methyltransferase BrxX

Expression

Induction

Transcribed at slowly increasing levels as cells progress from lag to exponential to stationary phase.

Interaction

Subunit

Interacts with phage T7 protein Ocr (AC P03775, gene 0.3) during an infection and when the protein is expressed from a plasmid.

Family & Domains

Sequence similarities

Family and domain databases

Sequence

  • Sequence status
    Complete
  • Length
    1,205
  • Mass (Da)
    137,965
  • Last updated
    2021-06-02 v1
  • Checksum
    22E426D20634029C
MNTNNIKKYAPQARNDFRDAVIQKLTTLGIAADKKGNLQIAEAETIGETVRYGQFDYPLSTLPRRERLVKRAREQGFEVLVEHCAYTWFNRLCAIRYMELHGYLDHGFRMLSHPETPTAFEVLDHVPEVAEALLPESKAQLVEMKLSGNQDEALYRELLLGQCHALHHAMPFLFEAVDDEAELLLPDNLTRTDSILRGLVDDIPEEDWEQVEVIGWLYQFYISEKKDAVIGKVVKSEDIPAATQLFTPNWIVQYLVQNSVGRQWLQTYPDSPLKDKMEYYIEPAEQTPEVQAQLAAITPASIEPESIKVLDPACGSGHILTEAYNVLKAIYEERGYRTRDIPQLILENNIFGLDIDDRAAQLSGFAMLMLARQDDRRILGRGVRLNIVSLQESKLDIAEVWTKLNFHQHMQRGSMGDMFTQGTALANTDSAEYKLLMRTLALFTSAKTLGSLIQVPQEDEAALKAFLERLYRLAVEGDIQQKEAAAELIPYIQQAWILAQRYDAVVANPPYMGGKGMNGDLKEFAKKQFPDSKSDLFAMFMQHAFSLLKENGFNAQVNMQSWMFLSSYEALRGWLLDNKTFITMAHLGARAFGQISGEVVQTTAWVIKNNHSGFYKPVFFRLVDDNEEHKKNNLLNRMNCFKNTLQNDFKKIPGSPIAYWATLAFINSFLKLPALGTRAVKGLDTNGSIDVFLRRWPEVSINSFDALGKGNSKWFPIAKGGELRKWFGNHEYIINYENDGIELRKNKANLRNKDMYFQEGGTWTVVSTTGFSMRYMPKGFLFDQGGSAVFCENNDELSIYNILACMNSKYINYSASLICPTLNFTTGDVRKFPVIKNNHLEDLAKKAIEISKADWNQFETSWEFSKNKLIEHKGNVAYSYASYCNFQDKLYEQLVNIEKNINNIIEEILGFKIETTENSELITLNSNKIYRYGQSETNDTFLNRHRSDTISELISYSVGCQMGRYSLDREGLVYAHEGNKGFAELAAEGAYKTFPADNDGILPLMDDEWFEDDVTSRVKEFVRTVWGEEHLQENLEFIAESLCLYAIKPKKGESALETIRRYLSTQFWKDHMKMYKKRPIYWLFSSGKEKAFECLVYLHRYNDATLSRMRTEYVVPLLARYQANIDRLNDQLDEASGGEATRLKRERDSLIKKFSELRSYDDRLRHYADMRISIDLDDGVKVNYGKFGDLLADVKAITGNAPEAI

Keywords

Sequence databases

Nucleotide SequenceProtein SequenceMolecule TypeStatus
CP000802
EMBL· GenBank· DDBJ
ABV04727.1
EMBL· GenBank· DDBJ
Genomic DNA

Genome annotation databases

Similar Proteins

Disclaimer

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