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Protein

Antitoxin RelB

Gene

relB

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. Counteracts the effect of cognate toxin RelE via direct protein-protein interaction, preventing RelE from entering the ribosome A site and thus inhibiting its endoribonuclease activity. An autorepressor of relBE operon transcription. 2 RelB dimers bind to 2 operator sequences; DNA-binding and repression is stronger when complexed with toxin/corepressor RelE by conditional cooperativity (PubMed:18501926, PubMed:22981948). Increased transcription rate of relBE and activation of relE is consistent with a lower level of RelB in starved cells due to degradation of RelB by protease Lon.10 Publications
Seems to be a principal mediator of cell death in liquid media.1 Publication

Miscellaneous

A number of site directed mutants give rise to a delayed relaxed phenotype; RNA synthesis resumes 10 minutes after amino acid starvation, an unusually slow recovery from periods of starvation, accumulation of a translation inhibitor.1 Publication
There are estimated to be 550-1100 RelB and 50-100 RelE molecules in rapidly growing cells of MG1655; as they have quite high affinity for each other (dissociation constant of 0.33 nM) there is probably less than 1 free RelE molecule per cell. The RelB2-RelE complex has a half-life of over 70 minutes.1 Publication

GO - Molecular functioni

GO - Biological processi

Keywordsi

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

Enzyme and pathway databases

BioCyciEcoCyc:EG10836-MONOMER
MetaCyc:EG10836-MONOMER

Names & Taxonomyi

Protein namesi
Recommended name:
Antitoxin RelB1 Publication
Gene namesi
Name:relB
Ordered Locus Names:b1564, JW1556
OrganismiEscherichia coli (strain K12)
Taxonomic identifieri83333 [NCBI]
Taxonomic lineageiBacteriaProteobacteriaGammaproteobacteriaEnterobacteralesEnterobacteriaceaeEscherichia
Proteomesi
  • UP000000318 Componenti: Chromosome
  • UP000000625 Componenti: Chromosome

Organism-specific databases

EcoGeneiEG10836 relB

Subcellular locationi

GO - Cellular componenti

Pathology & Biotechi

Disruption phenotypei

Essential, it cannot be deleted if a copy of relE remains in the cell. Cells missing relBE have a higher steady-state level of translation during amino acid starvation than wild-type cells. They survive antibiotic treatment in log phase better than wild-type cells. Cells missing mazE-mazF survive hydroxyurea treatment better than wild-type; further disruption of relE-relB and tonB yields even better survival (PubMed:20005847).3 Publications

Mutagenesis

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Mutagenesisi7R → A: Loss of DNA binding, 100-fold derepression of operon, still binds RelE. 2 Publications1
Mutagenesisi8I → A: 43-fold derepression of operon, partial loss of DNA-binding, still binds RelE. 1 Publication1
Mutagenesisi13K → A: 83-fold derepression of operon, loss of DNA-binding, still binds RelE. 1 Publication1
Mutagenesisi28S → L or R: 100-fold derepression of operon, loss of DNA-binding, still binds RelE. 1 Publication1
Mutagenesisi39A → T in relB101; a delayed relaxed phenotype. 1 Publication1
Mutagenesisi45P → L in relB102; a delayed relaxed phenotype. 1 Publication1
Mutagenesisi45P → T in relB35; a delayed relaxed phenotype. 1 Publication1
Mutagenesisi66 – 79Missing : Protein no longer tetramerizes. 1 PublicationAdd BLAST14
Mutagenesisi71 – 79Missing : Protein still tetramerizes. 1 Publication9

PTM / Processingi

Molecule processing

Feature keyPosition(s)DescriptionActionsGraphical viewLength
ChainiPRO_00000972431 – 79Antitoxin RelBAdd BLAST79

Post-translational modificationi

Probably degraded by Lon protease during amino acid starvation (PubMed:11717402). Degraded in vitro by Lon (PubMed:19747491).2 Publications

Proteomic databases

PaxDbiP0C079
PRIDEiP0C079

Expressioni

Inductioni

By amino acid starvation, by glucose starvation and by chloramphenicol; induction is independent of ppGpp. Autorepressed by RelB, RelE acts as a corepressor (PubMed:9767574, PubMed:19747491, PubMed:18501926, PubMed:22981948). Member of the relBEF operon (PubMed:2990907). Operon induced by ectopic expression of toxins HicA, HipA, MazF, MqsR and RelE, but not by YafQ (PubMed:23432955).8 Publications

Gene expression databases

CollecTFiEXPREG_000008a0

Interactioni

Subunit structurei

Homotetramer formed by dimerization of dimers in solution (PubMed:19747491, PubMed:18501926). Forms an RelB2-RelE2 heterotetramer (PubMed:18501926, PubMed:22981948). Also forms an RelB2-RelE heterotrimer (PubMed:18532983, PubMed:19747491). The RelB2-RelE complex is probably the one that binds DNA and represses transcription, possibly as 2 heterotrimers, 1 bound to each of 2 operators (PubMed:22981948, PubMed:19747491).6 Publications

Binary interactionsi

WithEntry#Exp.IntActNotes
relEP0C0773EBI-1124503,EBI-549378

Protein-protein interaction databases

BioGridi4260244, 61 interactors
ComplexPortaliCPX-1081 RelBE toxin-antitoxin complex
DIPiDIP-48258N
IntActiP0C079, 6 interactors
STRINGi316385.ECDH10B_1696

Structurei

Secondary structure

179
Legend: HelixTurnBeta strandPDB Structure known for this area
Show more details

3D structure databases

ProteinModelPortaliP0C079
SMRiP0C079
ModBaseiSearch...
MobiDBiSearch...

Miscellaneous databases

EvolutionaryTraceiP0C079

Family & Domainsi

Domaini

Dimerizes and binds DNA via its N-terminus (residues 1-50), binds toxin RelE via the C-terminus (residues 47-79) (PubMed:18501926, PubMed:18532983). Tetramerization probably requires amino acids between residues 66 and 71 (PubMed:18501926).2 Publications

Sequence similaritiesi

Belongs to the RelB/DinJ antitoxin family.Curated

Phylogenomic databases

eggNOGiCOG3077 LUCA
HOGENOMiHOG000008424
KOiK18918
OMAiMSAVTFR

Family and domain databases

Gene3Di1.10.1220.10, 1 hit
InterProiView protein in InterPro
IPR013321 Arc_rbn_hlx_hlx
IPR007337 RelB/DinJ
PANTHERiPTHR38781 PTHR38781, 1 hit
PfamiView protein in Pfam
PF04221 RelB, 1 hit
TIGRFAMsiTIGR02384 RelB_DinJ, 1 hit

Sequencei

Sequence statusi: Complete.

P0C079-1 [UniParc]FASTAAdd to basket
« Hide
        10         20         30         40         50
MGSINLRIDD ELKARSYAAL EKMGVTPSEA LRLMLEYIAD NERLPFKQTL
60 70
LSDEDAELVE IVKERLRNPK PVRVTLDEL
Length:79
Mass (Da):9,071
Last modified:April 1, 1988 - v1
Checksum:i3DD2107337226FAD
GO

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
X02405 Genomic DNA Translation: CAA26250.1
U00096 Genomic DNA Translation: AAC74637.1
AP009048 Genomic DNA Translation: BAA15263.1
PIRiA22830 BVECRB
RefSeqiNP_416082.1, NC_000913.3
WP_000534858.1, NZ_LN832404.1

Genome annotation databases

EnsemblBacteriaiAAC74637; AAC74637; b1564
BAA15263; BAA15263; BAA15263
GeneIDi32440941
948308
KEGGiecj:JW1556
eco:b1564
PATRICifig|1411691.4.peg.698

Similar proteinsi

Entry informationi

Entry nameiRELB_ECOLI
AccessioniPrimary (citable) accession number: P0C079
Secondary accession number(s): P07007
Entry historyiIntegrated into UniProtKB/Swiss-Prot: April 1, 1988
Last sequence update: April 1, 1988
Last modified: June 20, 2018
This is version 101 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
UniProt is an ELIXIR core data resource
Main funding by: National Institutes of Health

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