UniProtKB - P0AE70 (MAZF_ECOLI)
Protein
Endoribonuclease toxin MazF
Gene
mazF
Organism
Escherichia coli (strain K12)
Status
Functioni
Toxic component of a type II toxin-antitoxin (TA) system. A sequence-specific endoribonuclease it inhibits protein synthesis by cleaving mRNA and inducing bacterial stasis. It is stable, single-strand specific with mRNA cleavage independent of the ribosome, although translation enhances cleavage for some mRNAs (PubMed:18854355). Cleavage occurs at the 5'-end of ACA sequences, yielding a 2',3'-cyclic phosphate and a free 5'-OH, although cleavage can also occur on the 3'-end of the first A (PubMed:15537630, PubMed:23280569). Digests 16S rRNA in vivo 43 nts upstream of the C-terminus; this removes the anti-Shine-Dalgarno sequence forming a mixed population of wild-type and 'stress ribosomes'. Stress ribosomes do not translate leader-containing mRNA but are proficient in translation of leaderless mRNA, which alters the protein expression profile of the cell; MazF produces some leaderless mRNA (PubMed:21944167). The toxic endoribonuclease activity is inhibited by its labile cognate antitoxin MazE. Toxicity results when the levels of MazE decrease in the cell, leading to mRNA degradation. This effect can be rescued by expression of MazE, but after 6 hours in rich medium overexpression of MazF leads to programmed cell death (PubMed:8650219, PubMed:11222603). MazF-mediated cell death occurs following a number of stress conditions in a relA-dependent fashion and only when cells are in log phase; sigma factor S (rpoS) protects stationary phase cells from MazF-killing (PubMed:15150257, PubMed:19251848). Cell growth and viability are not affected when MazF and MazE are coexpressed. Both MazE and MazE-MazF bind to the promoter region of the mazE-mazF operon to inhibit their own transcription. MazE has higher affinity for promoter DNA in the presence of MazF (PubMed:25564525). 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 mRNA produced (PubMed:23432955).11 Publications
Might also serve to protect cells against bacteriophage; in the presence of MazE-MazF fewer P1 phages are produced than in a disrupted strain. For strain K38 most wild-type cells are killed but not by phage lysis; it was suggested that MazE-MazF causes P1 phage exclusion from the bacterial population. This phenomenon is strain dependent.1 Publication
The physiological role of this TA system is debated. Programmed cell death (PCD) occurs when cells are at high density and depends on the presence of MazE-MazF and a quorum sensing pentapeptide, the extracellular death factor (EDF) with sequence Asn-Asn-Trp-Asn-Asn (NNWNN), probably produced from the zwf gene product glucose-6-phosphate 1-dehydrogenase (PubMed:17962566, PubMed:18310334). Cell death governed by the MazE-MazF and DinJ-YafQ TA systems seems to play a role in biofilm formation, while MazE-MazF is also implicated in cell death in liquid media (PubMed:19707553). Implicated in hydroxy radical-mediated cell death induced by hydroxyurea treatment (PubMed:20005847, PubMed:23416055). In conjunction with EDF prevents apoptotic-like death (ALD) in the presence of DNA damaging agents, probably by reducing recA mRNA levels in a non-endonuclease-mediated manner (PubMed:22412352). Other studies (in strains BW25113 and MC4100, the latter makes EDF) demonstrate MazF does not cause PCD but instead bacteriostasis and possibly a dormant state as well as persister cell generation (PubMed:24375411). mRNA interferases play a role in bacterial persistence to antibiotics; overexpression of this protein induces persisters resistant to ciprofloxacin and ampicillin (PubMed:21788497).10 Publications
Caution
Strain K12 / MG1655 is deficient in both production and response to EDF, unlike strains K12 / MC4100, K12 / W3110 and K12 / K38, all of which make and respond to EDF.1 Publication
Activity regulationi
(Microbial infection) RNA cleavage activity is reduced when ADP-ribosylated.1 Publication
Inhibited by Mg2+ (PubMed:15537630). Stimulated in vitro in a concentration-dependent fashion by EDF, which is able to overcome inhibition by cognate antitoxin MazE (PubMed:21419338). The TA system is antagonized by stress response kinase SrkA, but probably not by phosphorylation of MazF (PubMed:23416055).3 Publications
GO - Molecular functioni
- DNA binding Source: UniProtKB-KW
- endoribonuclease activity Source: UniProtKB
- protein-containing complex binding Source: CAFA
- protein homodimerization activity Source: CAFA
- RNA binding Source: UniProtKB-KW
GO - Biological processi
- defense response to virus Source: UniProtKB-KW
- mRNA catabolic process Source: UniProtKB
- negative regulation of cell growth Source: UniProtKB
- positive regulation of programmed cell death Source: CACAO
- quorum sensing Source: UniProtKB-KW
- regulation of translation Source: UniProtKB-KW
- rRNA catabolic process Source: UniProtKB
Keywordsi
Molecular function | DNA-binding, Endonuclease, Hydrolase, Nuclease, Repressor, RNA-binding |
Biological process | Antiviral defense, Quorum sensing, Stress response, Toxin-antitoxin system, Transcription, Transcription regulation, Translation regulation |
Enzyme and pathway databases
BioCyci | EcoCyc:EG11249-MONOMER MetaCyc:EG11249-MONOMER |
Names & Taxonomyi
Protein namesi | Recommended name: Endoribonuclease toxin MazF (EC:3.1.27.-1 Publication)Alternative name(s): Toxin MazF mRNA interferase MazF1 Publication |
Gene namesi | Name:mazF Synonyms:chpA, chpAK Ordered Locus Names:b2782, JW2753 |
Organismi | Escherichia coli (strain K12) |
Taxonomic identifieri | 83333 [NCBI] |
Taxonomic lineagei | Bacteria › Proteobacteria › Gammaproteobacteria › Enterobacterales › Enterobacteriaceae › Escherichia › |
Proteomesi |
|
Pathology & Biotechi
Biotechnological usei
Can be used to produce large quantities of a single protein if the gene coding for the protein does not contain any ACA codons. Up to 90% of expressed bacterial cellular protein can be the target, which can be produced for up to 4 days. The system also works in eukaryotic cells.1 Publication
Disruption phenotypei
Decreased sensitivity to dramatic intracellular increases of ppGpp. Cells missing mazE-mazF survive high temperature, various DNA-damaging agents and H2O2 exposure better than wild-type cells. Cells missing mazE-mazF produce more P1 phage than wild-type cells, while introduction of lysogens into a growing non-lysogenic disruption culture is lethal (PubMed:15316771). Cells missing mazE-mazF show reduced biofilm formation, and survive antibiotic treatment in log phase better than wild-type cells (PubMed:11222603, PubMed:19707553). However lag phase cells disrupted only for mazF had a lower survival rate than wild-type cells (PubMed:24375411). Cells missing mazE-mazF survive hydroxyurea treatment better than wild-type; further disruption of relE-relB and tonB yields even better survival (PubMed:20005847). Cells missing mazE-mazF undergo an apoptotic-like death (ALD) upon DNA damage characterized by membrane depolarization and DNA fragmentation; further disruption of recA prevents membrane depolarization (PubMed:22412352). Unlike the single srkA disruption mutant, a triple srkA-mazE-mazF disruption mutant shows no hyperlethality in the presence of nalidixic acid or UV light, suggesting SrkA has a negative effect on MazF (PubMed:23416055). 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).11 Publications
Mutagenesis
Feature key | Position(s) | DescriptionActions | Graphical view | Length |
---|---|---|---|---|
Mutagenesisi | 17 – 28 | FDPTK…EQAGH → GGGGGGGGGGG: Changes loop 1 to poly-G; loss of endoribonuclease activity. 1 PublicationAdd BLAST | 12 | |
Mutagenesisi | 17 – 28 | FDPTK…EQAGH → LGPPSGSQPAKR: Changes loop 1 to MazF6 M.tuberculosis sequence; loss of endoribonuclease activity. 1 PublicationAdd BLAST | 12 | |
Mutagenesisi | 17 – 28 | FDPTK…EQAGH → PDDSRGPVPSYS: Changes loop 1 to MazF M.xanthus sequence; loss of endoribonuclease activity. 1 PublicationAdd BLAST | 12 | |
Mutagenesisi | 24 | E → A: Greatly reduces toxicity, about 10-fold less RNA cleavage activity. Expression in the presence of wt MazF has a dominant-negative phenotype, causing cell death as it titrates out the MazE antitoxin; still activates operon transcription. 2 Publications | 1 | |
Mutagenesisi | 28 | H → A: No changes in toxicity. 1 Publication | 1 | |
Mutagenesisi | 53 – 61 | TQSKGYPFE → GGGGGGGG or GGGGGGGGGGG: Changes loop 2 to poly-G; reduces endoribonuclease activity, alters cleavage sites. 1 Publication | 9 | |
Mutagenesisi | 53 – 61 | TQSKGYPFE → SNLHRASEPGN: Changes loop 2 to MazF M.xanthus sequence; reduces endoribonuclease activity, alters cleavage sites. 1 Publication | 9 | |
Mutagenesisi | 53 – 61 | TQSKGYPFE → SNTALAAMPGN: Changes loop 2 to MazF6 M.tuberculosis sequence; reduces endoribonuclease activity, alters cleavage sites. 1 Publication | 9 |
Chemistry databases
ChEMBLi | CHEMBL1795096 |
PTM / Processingi
Molecule processing
Feature key | Position(s) | DescriptionActions | Graphical view | Length |
---|---|---|---|---|
ChainiPRO_0000201897 | 1 – 111 | Endoribonuclease toxin MazFAdd BLAST | 111 |
Amino acid modifications
Feature key | Position(s) | DescriptionActions | Graphical view | Length |
---|---|---|---|---|
Modified residuei | 4 | ADP-ribosylarginine1 Publication | 1 |
Post-translational modificationi
(Microbial infection) ADP-ribosylated by enterobacteria phage T4.1 Publication
Keywords - PTMi
ADP-ribosylationProteomic databases
jPOSTi | P0AE70 |
PaxDbi | P0AE70 |
PRIDEi | P0AE70 |
Expressioni
Inductioni
Expressed in exponentially growing cells. Induction has been reported to occur after amino acid starvation in a ppGpp-independent fashion and to be Lon protease-dependent (PubMed:12972253), but also to not occur after amino acid starvation and to be regulated by ppGpp (PubMed:8650219). Also induced in M9 minimal medium and by chloramphenicol treatment (PubMed:21944167). MazE alone and in combination with MazF, represses transcription of the mazE-mazF operon. Fis activates transcription. Part of the relA-mazE-mazF-mazG operon, there is also a second mazE-mazF specific promoter which is negatively autoregulated (PubMed:2844820, PubMed:8650219). Operon induced by ectopic expression of toxin RelE; operon induction by amino acid starvation requires the relBEF operon (PubMed:23432955).7 Publications
Interactioni
Subunit structurei
Probably a dimer.
Forms a heterohexamer composed of alternating toxin and antitoxin homodimers MazF2-MazE2-MazF2. The binding site of MazE and ssRNA or ssDNA are largely overlapping; the presence of only 1 MazE molecule inhibits mRNA endoribonuclease activity. Binds to EDF but not a mutated EDF (NNGNN) (PubMed:21419338).
5 PublicationsGO - Molecular functioni
- protein homodimerization activity Source: CAFA
Protein-protein interaction databases
BioGRIDi | 4262300, 13 interactors |
ComplexPortali | CPX-1086, MazEF toxin-antitoxin complex |
IntActi | P0AE70, 2 interactors |
STRINGi | 511145.b2782 |
Chemistry databases
BindingDBi | P0AE70 |
Structurei
Secondary structure
Legend: HelixTurnBeta strandPDB Structure known for this area
Show more details3D structure databases
BMRBi | P0AE70 |
SMRi | P0AE70 |
ModBasei | Search... |
PDBe-KBi | Search... |
Miscellaneous databases
EvolutionaryTracei | P0AE70 |
Family & Domainsi
Region
Feature key | Position(s) | DescriptionActions | Graphical view | Length |
---|---|---|---|---|
Regioni | 17 – 28 | Loop 1, participates in catalytic activity1 PublicationAdd BLAST | 12 | |
Regioni | 53 – 61 | Loop 2, involved in substrate recognition1 Publication | 9 |
Domaini
Loop 1 (residues 17-28) effects catalytic activity while recognition of the ACA cleavage site is influenced by loop 2 (residues 53-61). Alterations of loop 2 generate new cleavage sites in addition to retaining the original cleavage site.1 Publication
Sequence similaritiesi
Belongs to the PemK/MazF family.Curated
Phylogenomic databases
eggNOGi | COG2337, Bacteria |
HOGENOMi | CLU_121823_2_3_6 |
InParanoidi | P0AE70 |
PhylomeDBi | P0AE70 |
Family and domain databases
DisProti | DP00299 |
Gene3Di | 2.30.30.110, 1 hit |
InterProi | View protein in InterPro IPR003477, PemK-like IPR011067, Plasmid_toxin/cell-grow_inhib |
PANTHERi | PTHR33988, PTHR33988, 1 hit |
Pfami | View protein in Pfam PF02452, PemK_toxin, 1 hit |
i Sequence
Sequence statusi: Complete.
P0AE70-1 [UniParc]FASTAAdd to basket
10 20 30 40 50
MVSRYVPDMG DLIWVDFDPT KGSEQAGHRP AVVLSPFMYN NKTGMCLCVP
60 70 80 90 100
CTTQSKGYPF EVVLSGQERD GVALADQVKS IAWRARGATK KGTVAPEELQ
110
LIKAKINVLI G
Sequence databases
Select the link destinations: EMBLi GenBanki DDBJi Links Updated | D16450 Genomic DNA Translation: BAA03918.1 J04039 Unassigned DNA Translation: AAA03239.1 U29580 Genomic DNA Translation: AAA69292.1 U00096 Genomic DNA Translation: AAC75824.1 AP009048 Genomic DNA Translation: BAE76856.1 |
PIRi | B49339 |
RefSeqi | NP_417262.1, NC_000913.3 WP_000254738.1, NZ_STEB01000030.1 |
Genome annotation databases
EnsemblBacteriai | AAC75824; AAC75824; b2782 BAE76856; BAE76856; BAE76856 |
GeneIDi | 58459985 947252 |
KEGGi | ecj:JW2753 eco:b2782 |
PATRICi | fig|1411691.4.peg.3953 |
Similar proteinsi
Cross-referencesi
Sequence databases
Select the link destinations: EMBLi GenBanki DDBJi Links Updated | D16450 Genomic DNA Translation: BAA03918.1 J04039 Unassigned DNA Translation: AAA03239.1 U29580 Genomic DNA Translation: AAA69292.1 U00096 Genomic DNA Translation: AAC75824.1 AP009048 Genomic DNA Translation: BAE76856.1 |
PIRi | B49339 |
RefSeqi | NP_417262.1, NC_000913.3 WP_000254738.1, NZ_STEB01000030.1 |
3D structure databases
Select the link destinations: PDBei RCSB PDBi PDBji Links Updated | PDB entry | Method | Resolution (Å) | Chain | Positions | PDBsum |
1UB4 | X-ray | 1.70 | A/B | 2-111 | [»] | |
3NFC | X-ray | 2.00 | A/B/C/D/E/F | 1-111 | [»] | |
5CK9 | X-ray | 1.90 | A/B | 1-111 | [»] | |
5CKB | X-ray | 2.80 | A/B | 1-111 | [»] | |
5CKD | X-ray | 1.70 | A/B | 1-111 | [»] | |
5CKE | X-ray | 2.31 | A/B | 1-111 | [»] | |
5CKF | X-ray | 2.80 | A/B | 1-111 | [»] | |
5CKH | X-ray | 2.45 | A/B | 1-111 | [»] | |
5CO7 | X-ray | 3.49 | A/B/C/D/E/F | 1-111 | [»] | |
5CQX | X-ray | 1.63 | A/B | 1-111 | [»] | |
5CQY | X-ray | 2.48 | A/B | 1-111 | [»] | |
5CR2 | X-ray | 2.90 | A/B/C | 1-111 | [»] | |
BMRBi | P0AE70 | |||||
SMRi | P0AE70 | |||||
ModBasei | Search... | |||||
PDBe-KBi | Search... |
Protein-protein interaction databases
BioGRIDi | 4262300, 13 interactors |
ComplexPortali | CPX-1086, MazEF toxin-antitoxin complex |
IntActi | P0AE70, 2 interactors |
STRINGi | 511145.b2782 |
Chemistry databases
BindingDBi | P0AE70 |
ChEMBLi | CHEMBL1795096 |
Proteomic databases
jPOSTi | P0AE70 |
PaxDbi | P0AE70 |
PRIDEi | P0AE70 |
Genome annotation databases
EnsemblBacteriai | AAC75824; AAC75824; b2782 BAE76856; BAE76856; BAE76856 |
GeneIDi | 58459985 947252 |
KEGGi | ecj:JW2753 eco:b2782 |
PATRICi | fig|1411691.4.peg.3953 |
Organism-specific databases
EchoBASEi | EB1229 |
Phylogenomic databases
eggNOGi | COG2337, Bacteria |
HOGENOMi | CLU_121823_2_3_6 |
InParanoidi | P0AE70 |
PhylomeDBi | P0AE70 |
Enzyme and pathway databases
BioCyci | EcoCyc:EG11249-MONOMER MetaCyc:EG11249-MONOMER |
Miscellaneous databases
EvolutionaryTracei | P0AE70 |
PROi | PR:P0AE70 |
Family and domain databases
DisProti | DP00299 |
Gene3Di | 2.30.30.110, 1 hit |
InterProi | View protein in InterPro IPR003477, PemK-like IPR011067, Plasmid_toxin/cell-grow_inhib |
PANTHERi | PTHR33988, PTHR33988, 1 hit |
Pfami | View protein in Pfam PF02452, PemK_toxin, 1 hit |
ProtoNeti | Search... |
MobiDBi | Search... |
Entry informationi
Entry namei | MAZF_ECOLI | |
Accessioni | P0AE70Primary (citable) accession number: P0AE70 Secondary accession number(s): P33645, Q2MA50 | |
Entry historyi | Integrated into UniProtKB/Swiss-Prot: | December 6, 2005 |
Last sequence update: | December 6, 2005 | |
Last modified: | April 7, 2021 | |
This is version 119 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 - SIMILARITY comments
Index of protein domains and families