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Protein

Antitoxin MqsA

Gene

mqsA

Organism
Escherichia coli (strain K12)
Status
Reviewed-Annotation score: Annotation score: 5 out of 5-Experimental evidence at protein leveli

Functioni

Antitoxin component of a type II toxin-antitoxin (TA) module. 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 modules 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 modules 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
  • transcription, DNA-templated Source: UniProtKB-KW
Complete GO annotation...

Keywords - Molecular functioni

Repressor

Keywords - Biological processi

Stress response, Transcription, Transcription regulation

Keywords - Ligandi

DNA-binding, Metal-binding, Zinc

Enzyme and pathway databases

BioCyciEcoCyc:G7571-MONOMER.
ECOL316407:JW2989-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-MqsA(2)-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

WithEntry#Exp.IntActNotes
infAP692222EBI-1120353,EBI-1120746
pldBP070002EBI-1120353,EBI-9134416
rbsRP0ACQ03EBI-1120353,EBI-1119646
rpmAP0A7L82EBI-1120353,EBI-546875
rpoEP0AGB62EBI-1120353,EBI-1129580
ybfEP0AAU72EBI-1120353,EBI-9138393

Protein-protein interaction databases

BioGridi4259247. 153 interactors.
DIPiDIP-12226N.
IntActiQ46864. 54 interactors.
STRINGi511145.b3021.

Structurei

Secondary structure

1131
Legend: HelixTurnBeta strandPDB Structure known for this area
Show more details
Feature keyPosition(s)DescriptionActionsGraphical viewLength
Turni4 – 6Combined sources3
Beta strandi7 – 22Combined sources16
Beta strandi25 – 37Combined sources13
Turni38 – 40Combined sources3
Beta strandi43 – 45Combined sources3
Helixi47 – 66Combined sources20
Helixi71 – 80Combined sources10
Helixi85 – 92Combined sources8
Helixi98 – 103Combined sources6
Helixi111 – 122Combined sources12
Helixi124 – 126Combined sources3
Helixi127 – 130Combined sources4

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...

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

Sequence similaritiesi

Contains 1 HTH cro/C1-type DNA-binding domain.PROSITE-ProRule annotation

Phylogenomic databases

eggNOGiENOG4105WJ3. Bacteria.
COG1396. LUCA.
HOGENOMiHOG000151625.
KOiK13655.
OMAiCGEGIWD.

Family and domain databases

Gene3Di1.10.260.40. 1 hit.
InterProiIPR001387. Cro/C1-type_HTH.
IPR010982. Lambda_DNA-bd_dom.
IPR022452. MqsA.
IPR032758. MqsA/HigA-2.
IPR022453. Znf_MqsA-type.
[Graphical view]
PfamiPF15731. MqsA_antitoxin. 1 hit.
[Graphical view]
SMARTiSM00530. HTH_XRE. 1 hit.
[Graphical view]
SUPFAMiSSF47413. SSF47413. 1 hit.
TIGRFAMsiTIGR03830. CxxCG_CxxCG_HTH. 1 hit.
TIGR03831. YgiT_finger. 1 hit.
PROSITEiPS50943. HTH_CROC1. 1 hit.
[Graphical view]

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.
PATRICi32121456. VBIEscCol129921_3115.

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.
DIPiDIP-12226N.
IntActiQ46864. 54 interactors.
STRINGi511145.b3021.

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.
PATRICi32121456. VBIEscCol129921_3115.

Organism-specific databases

EchoBASEiEB2840.
EcoGeneiEG13022. mqsA.

Phylogenomic databases

eggNOGiENOG4105WJ3. Bacteria.
COG1396. LUCA.
HOGENOMiHOG000151625.
KOiK13655.
OMAiCGEGIWD.

Enzyme and pathway databases

BioCyciEcoCyc:G7571-MONOMER.
ECOL316407:JW2989-MONOMER.
MetaCyc:G7571-MONOMER.

Miscellaneous databases

EvolutionaryTraceiQ46864.
PROiQ46864.

Family and domain databases

Gene3Di1.10.260.40. 1 hit.
InterProiIPR001387. Cro/C1-type_HTH.
IPR010982. Lambda_DNA-bd_dom.
IPR022452. MqsA.
IPR032758. MqsA/HigA-2.
IPR022453. Znf_MqsA-type.
[Graphical view]
PfamiPF15731. MqsA_antitoxin. 1 hit.
[Graphical view]
SMARTiSM00530. HTH_XRE. 1 hit.
[Graphical view]
SUPFAMiSSF47413. SSF47413. 1 hit.
TIGRFAMsiTIGR03830. CxxCG_CxxCG_HTH. 1 hit.
TIGR03831. YgiT_finger. 1 hit.
PROSITEiPS50943. HTH_CROC1. 1 hit.
[Graphical view]
ProtoNetiSearch...

Entry informationi

Entry nameiMQSA_ECOLI
AccessioniPrimary (citable) accession number: Q46864
Secondary accession number(s): Q2M9H9
Entry historyi
Integrated into UniProtKB/Swiss-Prot: July 15, 1999
Last sequence update: November 1, 1996
Last modified: November 2, 2016
This is version 116 of the entry and version 1 of the sequence. [Complete history]
Entry statusiReviewed (UniProtKB/Swiss-Prot)
Annotation programProkaryotic Protein Annotation Program

Miscellaneousi

Keywords - Technical termi

3D-structure, Complete proteome, Reference proteome

Documents

  1. Escherichia coli
    Escherichia coli (strain K12): entries and cross-references to EcoGene
  2. PDB cross-references
    Index of Protein Data Bank (PDB) cross-references
  3. SIMILARITY comments
    Index of protein domains and families

Similar proteinsi

Links to similar proteins from the UniProt Reference Clusters (UniRef) at 100%, 90% and 50% sequence identity:
100%UniRef100 combines identical sequences and sub-fragments with 11 or more residues from any organism into one UniRef entry.
90%UniRef90 is built by clustering UniRef100 sequences that have at least 90% sequence identity to, and 80% overlap with, the longest sequence (a.k.a seed sequence).
50%UniRef50 is built by clustering UniRef90 seed sequences that have at least 50% sequence identity to, and 80% overlap with, the longest sequence in the cluster.