UniProtKB - Q46865 (MQSR_ECOLI)
Protein
mRNA interferase toxin MqsR
Gene
mqsR
Organism
Escherichia coli (strain K12)
Status
Functioni
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).7 Publications
Initially reported to act as a cotranscription factor with MqsA (PubMed:19690171, PubMed:20105222). Following further experiments, the MqsR-MqsA complex does not bind DNA and all reported data are actually due to a small fraction of free MqsA alone binding DNA. Addition of MqsR to a preformed MqsA-promoter DNA complex causes dissociation of the MqsA-DNA complex, probably causing derepression of MqsA-repressed transcripts. Does not bind DNA in the presence or absence of MqsA (PubMed:23172222).3 Publications
Temperature dependencei
The MqsR-MqsA complex is exceptionally thermostable with a Tm of 83.4 degress Celsius versus 48.1 degress Celsius for MqsR and 61.1 degress Celsius for MqsA.1 Publication
GO - Molecular functioni
- endoribonuclease activity Source: EcoCyc
GO - Biological processi
- negative regulation of transcription, DNA-templated Source: CACAO
- negative regulation of translation Source: EcoCyc
- quorum sensing Source: UniProtKB-KW
- regulation of cell motility Source: CACAO
- regulation of mRNA stability Source: EcoCyc
- single-species biofilm formation Source: EcoCyc
Keywordsi
Molecular function | Endonuclease, Hydrolase, Nuclease |
Biological process | Quorum sensing, Stress response, Toxin-antitoxin system, Transcription, Transcription regulation |
Enzyme and pathway databases
BioCyci | EcoCyc:G7572-MONOMER MetaCyc:G7572-MONOMER |
Names & Taxonomyi
Protein namesi | Recommended name: mRNA interferase toxin MqsR1 Publication (EC:3.1.-.-)Alternative name(s): Endoribonuclease MqsR Motility quorum-sensing regulator MqsR1 Publication Toxin MqsR |
Gene namesi | Name:mqsR1 Publication Synonyms:ygiU Ordered Locus Names:b3022, JW2990 |
Organismi | Escherichia coli (strain K12) |
Taxonomic identifieri | 83333 [NCBI] |
Taxonomic lineagei | Bacteria › Proteobacteria › Gammaproteobacteria › Enterobacterales › Enterobacteriaceae › Escherichia › |
Proteomesi |
|
Pathology & Biotechi
Disruption phenotypei
No loss of ability to form persister cells in MG1655, represses persister cell formation in BW25113. Deletion decreases biofilm formation in LB medium (PubMed:16352847). Deletion has also been shown to increase biofilm formation (PubMed:20105222). Deletion at 48h, in flow cells, leads to a reduction in biomass, substratum coverage and changes the biofilm architecture from a 54 micron thick film with microcolonies to one with nearly no biomass and only a few colonies remaining. Deletion abolishes motility. A double mqsR-mqsA deletion leads to increased rpoS mRNA levels, resulting in increased cyclic-di-GMP levels, increasing stress resistance, increased biofilm formation (PubMed:21516113). The double mutant has increased metabolism and respiration in the presence of the bile acid deoxycholate and consequently grows less well. Decreases cell survival in the presence of 20% deoxycholate (PubMed:25534751). mRNA interferases play a role in bacterial persistence to antibiotics; as 10 mRNA interferases are successively deleted reduced levels of persisters are generated (PubMed:21788497).7 Publications
Mutagenesis
Feature key | Position(s) | DescriptionActions | Graphical view | Length |
---|---|---|---|---|
Mutagenesisi | 55 | Y → A: No change in toxicity. 1 Publication | 1 | |
Mutagenesisi | 56 | K → A: Loss of toxicity. 1 Publication | 1 | |
Mutagenesisi | 58 | M → A: No change in toxicity. 1 Publication | 1 | |
Mutagenesisi | 68 | Q → A: Loss of toxicity. 1 Publication | 1 | |
Mutagenesisi | 72 | R → A: No change in toxicity. 1 Publication | 1 | |
Mutagenesisi | 81 | Y → A: Loss of toxicity. 1 Publication | 1 | |
Mutagenesisi | 96 | K → A: Loss of toxicity. 1 Publication | 1 |
PTM / Processingi
Molecule processing
Feature key | Position(s) | DescriptionActions | Graphical view | Length |
---|---|---|---|---|
ChainiPRO_0000169411 | 1 – 98 | mRNA interferase toxin MqsRAdd BLAST | 98 |
Proteomic databases
PaxDbi | Q46865 |
PRIDEi | Q46865 |
Expressioni
Inductioni
Induced by amino acid starvation, glucose starvation and when translation is blocked. Also induced by nalidixic acid, azolocillin and H2O2 (PubMed:23289863). It has been suggested that MqsA represses its own operon (PubMed:19690171). Induction is decreased in the absence of the Lon protease suggesting, by homology to other toxin-antitoxin systems, that Lon may degrade the MqsA antitoxin. Transcription is activated by MqsA (PubMed:20105222). A member of the mqsRA operon. Most highly induced gene in persister cells (PubMed:16768798). Degrades its own transcript (PubMed:23172222). This operon induced by ectopic expression of toxins RelE, HicA and YafQ but not by MazF or HicA (PubMed:23432955).1 Publication5 Publications
Interactioni
Subunit structurei
Might be a dimer (PubMed:19690171). Also reported to be a monomer (PubMed:23172222). Crystallizes as a heterotetramer with MqsA, MqsR-MqsA2-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.
3 PublicationsProtein-protein interaction databases
BioGRIDi | 4260831, 22 interactors |
ComplexPortali | CPX-1084, MqsRA toxin-antitoxin complex |
IntActi | Q46865, 10 interactors |
STRINGi | 511145.b3022 |
Structurei
Secondary structure
Legend: HelixTurnBeta strandPDB Structure known for this area
Show more details3D structure databases
SMRi | Q46865 |
ModBasei | Search... |
PDBe-KBi | Search... |
Family & Domainsi
Phylogenomic databases
eggNOGi | ENOG5032TA0, Bacteria |
HOGENOMi | CLU_161157_0_0_6 |
Family and domain databases
CDDi | cd12869, MqsR, 1 hit |
Gene3Di | 3.30.2310.40, 1 hit |
InterProi | View protein in InterPro IPR038493, MqsR_sf IPR031451, MqsR_toxin |
Pfami | View protein in Pfam PF15723, MqsR_toxin, 1 hit |
i Sequence
Sequence statusi: Complete.
Q46865-1 [UniParc]FASTAAdd to basket
10 20 30 40 50
MEKRTPHTRL SQVKKLVNAG QVRTTRSALL NADELGLDFD GMCNVIIGLS
60 70 80 90
ESDFYKSMTT YSDHTIWQDV YRPRLVTGQV YLKITVIHDV LIVSFKEK
Sequence databases
Select the link destinations: EMBLi GenBanki DDBJi Links Updated | U28377 Genomic DNA Translation: AAA69190.1 U00096 Genomic DNA Translation: AAC76058.1 AP009048 Genomic DNA Translation: BAE77078.1 |
PIRi | D65089 |
RefSeqi | NP_417494.1, NC_000913.3 WP_000415584.1, NZ_SSZK01000023.1 |
Genome annotation databases
EnsemblBacteriai | AAC76058; AAC76058; b3022 BAE77078; BAE77078; BAE77078 |
GeneIDi | 947500 |
KEGGi | ecj:JW2990 eco:b3022 |
PATRICi | fig|1411691.4.peg.3708 |
Similar proteinsi
Cross-referencesi
Sequence databases
Select the link destinations: EMBLi GenBanki DDBJi Links Updated | U28377 Genomic DNA Translation: AAA69190.1 U00096 Genomic DNA Translation: AAC76058.1 AP009048 Genomic DNA Translation: BAE77078.1 |
PIRi | D65089 |
RefSeqi | NP_417494.1, NC_000913.3 WP_000415584.1, NZ_SSZK01000023.1 |
3D structure databases
Select the link destinations: PDBei RCSB PDBi PDBji Links Updated | PDB entry | Method | Resolution (Å) | Chain | Positions | PDBsum |
3HI2 | X-ray | 2.00 | B/D | 1-98 | [»] | |
SMRi | Q46865 | |||||
ModBasei | Search... | |||||
PDBe-KBi | Search... |
Protein-protein interaction databases
BioGRIDi | 4260831, 22 interactors |
ComplexPortali | CPX-1084, MqsRA toxin-antitoxin complex |
IntActi | Q46865, 10 interactors |
STRINGi | 511145.b3022 |
Proteomic databases
PaxDbi | Q46865 |
PRIDEi | Q46865 |
Genome annotation databases
EnsemblBacteriai | AAC76058; AAC76058; b3022 BAE77078; BAE77078; BAE77078 |
GeneIDi | 947500 |
KEGGi | ecj:JW2990 eco:b3022 |
PATRICi | fig|1411691.4.peg.3708 |
Organism-specific databases
EchoBASEi | EB2841 |
Phylogenomic databases
eggNOGi | ENOG5032TA0, Bacteria |
HOGENOMi | CLU_161157_0_0_6 |
Enzyme and pathway databases
BioCyci | EcoCyc:G7572-MONOMER MetaCyc:G7572-MONOMER |
Miscellaneous databases
PROi | PR:Q46865 |
Family and domain databases
CDDi | cd12869, MqsR, 1 hit |
Gene3Di | 3.30.2310.40, 1 hit |
InterProi | View protein in InterPro IPR038493, MqsR_sf IPR031451, MqsR_toxin |
Pfami | View protein in Pfam PF15723, MqsR_toxin, 1 hit |
ProtoNeti | Search... |
MobiDBi | Search... |
Entry informationi
Entry namei | MQSR_ECOLI | |
Accessioni | Q46865Primary (citable) accession number: Q46865 Secondary accession number(s): Q2M9H8 | |
Entry historyi | Integrated into UniProtKB/Swiss-Prot: | July 15, 1998 |
Last sequence update: | November 1, 1996 | |
Last modified: | April 7, 2021 | |
This is version 124 of the entry and version 1 of the sequence. See complete history. | ||
Entry statusi | Reviewed (UniProtKB/Swiss-Prot) | |
Annotation program | Prokaryotic Protein Annotation Program |
Miscellaneousi
Keywords - Technical termi
3D-structure, Reference proteomeDocuments
- PDB cross-references
Index of Protein Data Bank (PDB) cross-references