Detail Information for IndEnz0002015974
IED ID IndEnz0002015974
Enzyme Type ID protease015974
Protein Name Antitoxin MqsA
Gene Name mqsA ygiT b3021 JW2989
Organism Escherichia coli (strain K12)
Taxonomic Lineage cellular organisms Bacteria Proteobacteria Gammaproteobacteria Enterobacterales Enterobacteriaceae Escherichia Escherichia coli Escherichia coli (strain K12)
Enzyme Sequence MKCPVCHQGEMVSGIKDIPYTFRGRKTVLKGIHGLYCVHCEESIMNKEESDAFMAQVKAFRASVNAETVAPEFIVKVRKKLSLTQKEASEIFGGGVNAFSRYEKGNAQPHPSTIKLLRVLDKHPELLNEIR
Enzyme Length 131
Uniprot Accession Number Q46864
Absorption
Active Site
Activity Regulation
Binding Site
Calcium Binding
catalytic Activity
DNA Binding DNA_BIND 85..104; /note=H-T-H motif; /evidence=ECO:0000255|PROSITE-ProRule:PRU00257
EC Number
Enzyme Function FUNCTION: 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). {ECO:0000269|PubMed:19690171, ECO:0000269|PubMed:19943910, ECO:0000269|PubMed:20105222, ECO:0000269|PubMed:21516113, ECO:0000269|PubMed:23172222, ECO:0000269|PubMed:25534751, ECO:0000303|PubMed:24212724}.
Temperature Dependency BIOPHYSICOCHEMICAL PROPERTIES: Temperature dependence: 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. {ECO:0000269|PubMed:23172222};
PH Dependency
Pathway
nucleotide Binding
Features Beta strand (3); Chain (1); DNA binding (1); Domain (1); Helix (7); Metal binding (4); Mutagenesis (4); Turn (2)
Keywords 3D-structure;DNA-binding;Metal-binding;Reference proteome;Repressor;Stress response;Toxin-antitoxin system;Transcription;Transcription regulation;Zinc
Interact With P69222; P07000; P0ACQ0; P0A7L8; P0AGB6; P0AAU7
Induction INDUCTION: 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). {ECO:0000269|PubMed:16768798, ECO:0000269|PubMed:19943910, ECO:0000269|PubMed:20105222, ECO:0000269|PubMed:23432955, ECO:0000303|PubMed:19690171}.
Subcellular Location
Modified Residue
Post Translational Modification PTM: Degraded in the presence of oxidative stress, maybe by the Lon and/or ClpX proteases. {ECO:0000303|PubMed:20105222, ECO:0000303|PubMed:21516113}.
Signal Peptide
Structure 3D NMR spectroscopy (1); X-ray crystallography (5)
Cross Reference PDB 2KZ8; 3FMY; 3GA8; 3GN5; 3HI2; 3O9X;
Mapped Pubmed ID 15556475; 16606699; 24561554;
Motif
Gene Encoded By
Mass 14,703
Kinetics
Metal Binding METAL 3; /note="Zinc; structural"; /evidence="ECO:0000269|PubMed:20041169, ECO:0000269|PubMed:20823526, ECO:0000269|PubMed:21068382, ECO:0000269|PubMed:22789559"; METAL 6; /note="Zinc; structural"; /evidence="ECO:0000269|PubMed:20041169, ECO:0000269|PubMed:20823526, ECO:0000269|PubMed:21068382, ECO:0000269|PubMed:22789559"; METAL 37; /note="Zinc; structural"; /evidence="ECO:0000269|PubMed:20041169, ECO:0000269|PubMed:20823526, ECO:0000269|PubMed:21068382, ECO:0000269|PubMed:22789559"; METAL 40; /note="Zinc; structural"; /evidence="ECO:0000269|PubMed:20041169, ECO:0000269|PubMed:20823526, ECO:0000269|PubMed:21068382, ECO:0000269|PubMed:22789559"
Rhea ID
Cross Reference Brenda