mRNA interferase toxin MqsR - Q46865 (MQSR_ECOLI)

 

Protein Feature View of PDB entries mapped to a UniProtKB sequence  

  • Number of PDB entries for Q46865: 1
 
Function
Toxic component of a type II toxin-antitoxin (TA) system. Plays a significant role in the control of biofilm formation and induction of persister cells in the presence of antibiotics. An mRNA interferase which has been reported to be translation-independent (PubMed:19690171, PubMed:19943910, PubMed:23289863). It has also been reported to be translation-dependent (PubMed:20041169). Cleavage has been reported to occur on either side of G in the sequence GCU (PubMed:19690171). Also reported to cleave after C in GC(A/U) sequences (PubMed:19943910). There are only 14 genes in E.coli W3110 (and probably also MG1655) that do not have a GCU sequence and thus are resistant to the mRNA interferase activity; among these is the gene for toxin GhoT. Overexpression of MqsR causes cessation of cell growth and inhibits cell proliferation via inhibition of translation as well as increasing persister cell formation; these effects are overcome by concomitant or subsequent expression of antitoxin MqsA. Cross-talk can occur between different TA systems. Ectopic expression of this toxin induces transcription of the relBEF TA system operon with specific cleavage of the relBEF mRNA produced (PubMed:23432955). Regulates the expression of GhoT/GhoS, a type V TA system (PubMed:23289863). Persistence depends on toxin GhoT activity, which MqsR controls at the post-transcriptional level by selectively degrading the antitoxin ghoS segment of the ghoST mRNA (PubMed:23289863). Persister cells exhibit antibiotic tolerance without genetic change. mRNA interferases play a role in bacterial persistence to antibiotics; overexpression of this protein induces persisters resistant to coiprofloxacin and ampicillin (PubMed:21788497). Overexpression leads to a dramatic increase in tolerance to the antibiotic ofloxacin. This TA system mediates cell growth during bile acid deoxycholate stress by degrading mRNA for probable deoxycholate-binding protein YgiS; bile acid detergents such as deoxycholate are important for host defense against bacterial growth in the gall bladder and duodenum (PubMed:25534751). UniProt
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Subunit Structure
Might be a dimer (PubMed:19690171). Also reported to be a monomer (PubMed:23172222). Crystallizes as a heterotetramer with MqsA, MqsR-MqsA(2)-MqsR (PubMed:20041169). Purifies as a possible heterohexamer of 2 MqsR dimers and 1 MqsA dimer (PubMed:19690171). When the 2 dissociate the MsqR mRNA interferase becomes active. UniProt
  • Other Gene names: mqsR, ygiU, b3022, JW2990
This protein in other organisms (by gene name):
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  • Red: potentially disorderd region
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Data in lilac represent the genomic exon structure projected onto the UniProt sequence.
Data in blue originates from PDB
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The PDB to UniProt mapping is based on the data provided by the EBI SIFTS project. See also Velankar et al., Nucleic Acids Research 33, D262-265 (2005).
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