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Protein

Antitoxin MqsA

Gene

mqsA

Organism
Escherichia coli (strain K12)
Status
Reviewed-Annotation score: -Experimental evidence at protein leveli

Functioni

Antitoxin component of a type II toxin-antitoxin (TA) system. Labile antitoxin that binds to the MqsR mRNA interferase toxin and neutralizes its endoribonuclease activity. Overexpression prevents MqsR-mediated cessation of cell growth and inhibition of cell proliferation. 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 (PubMed:23172222). MqsA binds to 2 palindromes in the promoter region of the mqsRA operon activating its transcription. Binds to other promoters, inducing mcbR and spy and repressing cspD among others (PubMed:20105222). Binds to and represses the rpoS promoter, the master stress regulator, resulting in decreased cyclic-di-GMP, reduced stress resistance, increased cell motility and decreased biofilm formation; in these experiments 5 TA systems are missing (lacks MazEF, RelEB, ChpB, YoeB-YefM, YafQ-DinJ) (PubMed:21516113). An earlier study showed overexpression alone increases biofilm formation, perhaps by repressing cspD; in these experiments the 5 TA systems are present (PubMed:20105222). Represses the csgD promoter. In the presence of stress, when this protein is degraded, the promoters it represses are derepressed, leading to biofilm formation (Probable). 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).1 Publication6 Publications

Cofactori

Zn2+4 PublicationsNote: Binds 1 Zn2+ ion per subunit.4 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

Sites

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Metal bindingi3Zinc; structural4 Publications1
Metal bindingi6Zinc; structural4 Publications1
Metal bindingi37Zinc; structural4 Publications1
Metal bindingi40Zinc; structural4 Publications1

Regions

Feature keyPosition(s)DescriptionActionsGraphical viewLength
DNA bindingi85 – 104H-T-H motifPROSITE-ProRule annotationAdd BLAST20

GO - Molecular functioni

  • metal ion binding Source: UniProtKB-KW
  • sequence-specific DNA binding Source: EcoCyc

GO - Biological processi

  • regulation of transcription, DNA-templated Source: EcoCyc

Keywordsi

Molecular functionDNA-binding, Repressor
Biological processStress response, Toxin-antitoxin system, Transcription, Transcription regulation
LigandMetal-binding, Zinc

Enzyme and pathway databases

BioCyciEcoCyc:G7571-MONOMER
MetaCyc:G7571-MONOMER

Names & Taxonomyi

Protein namesi
Recommended name:
Antitoxin MqsA1 Publication
Gene namesi
Name:mqsA1 Publication
Synonyms:ygiT
Ordered Locus Names:b3021, JW2989
OrganismiEscherichia coli (strain K12)
Taxonomic identifieri83333 [NCBI]
Taxonomic lineageiBacteriaProteobacteriaGammaproteobacteriaEnterobacteralesEnterobacteriaceaeEscherichia
Proteomesi
  • UP000000318 Componenti: Chromosome
  • UP000000625 Componenti: Chromosome

Organism-specific databases

EcoGeneiEG13022 mqsA

Pathology & Biotechi

Disruption phenotypei

Essential for growth, it cannot be disrupted (PubMed:16768798). 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).3 Publications

Mutagenesis

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Mutagenesisi61R → A or D: Decreases DNA-binding, decreases thermostability of MqsR-MqsA complex. 1 Publication1
Mutagenesisi97 – 101NAFSR → AAFSA: Abolishes DNA-binding, including binding to the rpoS promoter. 2 Publications5
Mutagenesisi97N → A: 50-fold reduction in DNA-binding. 1 Publication1
Mutagenesisi101R → A: 10-fold reduction in DNA-binding. 1 Publication1

PTM / Processingi

Molecule processing

Feature keyPosition(s)DescriptionActionsGraphical viewLength
ChainiPRO_00001497621 – 131Antitoxin MqsAAdd BLAST131

Post-translational modificationi

Degraded in the presence of oxidative stress, maybe by the Lon and/or ClpX proteases.2 Publications

Proteomic databases

PaxDbiQ46864
PRIDEiQ46864

Expressioni

Inductioni

Induced by amino acid starvation, glucose starvation and when translation is blocked. 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). It has been suggested that MqsA represses its own operon (PubMed:19690171). Not more induced in persister cells (PubMed:16768798). A member of the mqsRA operon. This operon induced by ectopic expression of toxins RelE, HicA and YafQ but not by MazF or HicA (PubMed:23432955).1 Publication4 Publications

Interactioni

Subunit structurei

Homodimer. Crystallizes as a heterotetramer with MqsA, MqsR-MqsA2-MqsR (PubMed:20041169). Purifies as a probable heterohexamer of 2 MqsR dimers and 1 MqsA dimer (PubMed:19690171). Binds promoter DNA as a dimer (PubMed:21068382). When the 2 dissociate the MsqR mRNA interferase becomes active.4 Publications

Binary interactionsi

Protein-protein interaction databases

BioGridi4259247, 153 interactors
ComplexPortaliCPX-1084 MqsRA toxin-antitoxin complex
DIPiDIP-12226N
IntActiQ46864, 54 interactors
STRINGi316385.ECDH10B_3195

Structurei

Secondary structure

1131
Legend: HelixTurnBeta strandPDB Structure known for this area
Show more details

3D structure databases

ProteinModelPortaliQ46864
SMRiQ46864
ModBaseiSearch...
MobiDBiSearch...

Miscellaneous databases

EvolutionaryTraceiQ46864

Family & Domainsi

Domains and Repeats

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Domaini74 – 127HTH cro/C1-typePROSITE-ProRule annotationAdd BLAST54

Domaini

The Zn-binding N-terminal domain (residues 1-65) binds to the MqsR mRNA interferase toxin and makes contact with the DNA phosphate backbone, while the C-terminus (residues 70-131) binds the promoter in a sequence-specific manner. They are linked by a short flexible domain (PubMed:22789559).3 Publications

Phylogenomic databases

eggNOGiENOG4105WJ3 Bacteria
COG1396 LUCA
HOGENOMiHOG000151625
KOiK13655

Family and domain databases

CDDicd00093 HTH_XRE, 1 hit
InterProiView protein in InterPro
IPR001387 Cro/C1-type_HTH
IPR010982 Lambda_DNA-bd_dom_sf
IPR022452 MqsA
IPR032758 MqsA/HigA-2
IPR022453 Znf_MqsA-type
PfamiView protein in Pfam
PF15731 MqsA_antitoxin, 1 hit
SMARTiView protein in SMART
SM00530 HTH_XRE, 1 hit
SUPFAMiSSF47413 SSF47413, 1 hit
TIGRFAMsiTIGR03830 CxxCG_CxxCG_HTH, 1 hit
TIGR03831 YgiT_finger, 1 hit
PROSITEiView protein in PROSITE
PS50943 HTH_CROC1, 1 hit

Sequencei

Sequence statusi: Complete.

Q46864-1 [UniParc]FASTAAdd to basket
« Hide
        10         20         30         40         50
MKCPVCHQGE MVSGIKDIPY TFRGRKTVLK GIHGLYCVHC EESIMNKEES
60 70 80 90 100
DAFMAQVKAF RASVNAETVA PEFIVKVRKK LSLTQKEASE IFGGGVNAFS
110 120 130
RYEKGNAQPH PSTIKLLRVL DKHPELLNEI R
Length:131
Mass (Da):14,703
Last modified:November 1, 1996 - v1
Checksum:iAA26A2793AD84447
GO

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
U28377 Genomic DNA Translation: AAA69189.1
U00096 Genomic DNA Translation: AAC76057.1
AP009048 Genomic DNA Translation: BAE77077.1
PIRiC65089
RefSeqiNP_417493.1, NC_000913.3
WP_000650107.1, NZ_LN832404.1

Genome annotation databases

EnsemblBacteriaiAAC76057; AAC76057; b3021
BAE77077; BAE77077; BAE77077
GeneIDi945814
KEGGiecj:JW2989
eco:b3021
PATRICifig|1411691.4.peg.3709

Similar proteinsi

Cross-referencesi

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
U28377 Genomic DNA Translation: AAA69189.1
U00096 Genomic DNA Translation: AAC76057.1
AP009048 Genomic DNA Translation: BAE77077.1
PIRiC65089
RefSeqiNP_417493.1, NC_000913.3
WP_000650107.1, NZ_LN832404.1

3D structure databases

Select the link destinations:
PDBei
RCSB PDBi
PDBji
Links Updated
PDB entryMethodResolution (Å)ChainPositionsPDBsum
2KZ8NMR-A1-131[»]
3FMYX-ray1.40A62-131[»]
3GA8X-ray1.70A1-76[»]
3GN5X-ray2.15A/B1-131[»]
3HI2X-ray2.00A/C1-76[»]
3O9XX-ray2.10A/B1-131[»]
ProteinModelPortaliQ46864
SMRiQ46864
ModBaseiSearch...
MobiDBiSearch...

Protein-protein interaction databases

BioGridi4259247, 153 interactors
ComplexPortaliCPX-1084 MqsRA toxin-antitoxin complex
DIPiDIP-12226N
IntActiQ46864, 54 interactors
STRINGi316385.ECDH10B_3195

Proteomic databases

PaxDbiQ46864
PRIDEiQ46864

Protocols and materials databases

Structural Biology KnowledgebaseSearch...

Genome annotation databases

EnsemblBacteriaiAAC76057; AAC76057; b3021
BAE77077; BAE77077; BAE77077
GeneIDi945814
KEGGiecj:JW2989
eco:b3021
PATRICifig|1411691.4.peg.3709

Organism-specific databases

EchoBASEiEB2840
EcoGeneiEG13022 mqsA

Phylogenomic databases

eggNOGiENOG4105WJ3 Bacteria
COG1396 LUCA
HOGENOMiHOG000151625
KOiK13655

Enzyme and pathway databases

BioCyciEcoCyc:G7571-MONOMER
MetaCyc:G7571-MONOMER

Miscellaneous databases

EvolutionaryTraceiQ46864
PROiPR:Q46864

Family and domain databases

CDDicd00093 HTH_XRE, 1 hit
InterProiView protein in InterPro
IPR001387 Cro/C1-type_HTH
IPR010982 Lambda_DNA-bd_dom_sf
IPR022452 MqsA
IPR032758 MqsA/HigA-2
IPR022453 Znf_MqsA-type
PfamiView protein in Pfam
PF15731 MqsA_antitoxin, 1 hit
SMARTiView protein in SMART
SM00530 HTH_XRE, 1 hit
SUPFAMiSSF47413 SSF47413, 1 hit
TIGRFAMsiTIGR03830 CxxCG_CxxCG_HTH, 1 hit
TIGR03831 YgiT_finger, 1 hit
PROSITEiView protein in PROSITE
PS50943 HTH_CROC1, 1 hit
ProtoNetiSearch...

Entry informationi

Entry nameiMQSA_ECOLI
AccessioniPrimary (citable) accession number: Q46864
Secondary accession number(s): Q2M9H9
Entry historyiIntegrated into UniProtKB/Swiss-Prot: July 15, 1999
Last sequence update: November 1, 1996
Last modified: November 7, 2018
This is version 126 of the entry and version 1 of the sequence. See complete history.
Entry statusiReviewed (UniProtKB/Swiss-Prot)
Annotation programProkaryotic Protein Annotation Program

Miscellaneousi

Keywords - Technical termi

3D-structure, Complete proteome, Reference proteome

Documents

  1. PDB cross-references
    Index of Protein Data Bank (PDB) cross-references
  2. Escherichia coli
    Escherichia coli (strain K12): entries and cross-references to EcoGene
UniProt is an ELIXIR core data resource
Main funding by: National Institutes of Health

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