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Protein

Stringent starvation protein B

Gene

sspB

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

Functioni

Enhances recognition of ssrA-tagged proteins by the ClpX-ClpP protease; the ssrA degradation tag (AANDENYALAA) is added trans-translationally to proteins that are stalled on the ribosome, freeing the ribosome and targeting stalled peptides for degradation. SspB activates the ATPase activity of ClpX. Seems to act in concert with SspA in the regulation of several proteins during exponential and stationary-phase growth.
Also stimulates degradation of the N-terminus of RseA (residues 1-108, alone or in complex with sigma-E) by ClpX-ClpP in a non-ssrA-mediated fashion.

GO - Biological processi

  • positive regulation of protein catabolic process Source: EcoCyc
Complete GO annotation...

Keywords - Biological processi

Stress response

Enzyme and pathway databases

BioCyciEcoCyc:EG10978-MONOMER.
ECOL316407:JW3197-MONOMER.

Names & Taxonomyi

Protein namesi
Recommended name:
Stringent starvation protein B
Alternative name(s):
Adapter protein SspB
Specificity-enhancing factor SspB
Gene namesi
Name:sspB
Ordered Locus Names:b3228, JW3197
OrganismiEscherichia coli (strain K12)
Taxonomic identifieri83333 [NCBI]
Taxonomic lineageiBacteriaProteobacteriaGammaproteobacteriaEnterobacterialesEnterobacteriaceaeEscherichia
Proteomesi
  • UP000000318 Componenti: Chromosome
  • UP000000625 Componenti: Chromosome

Organism-specific databases

EcoGeneiEG10978. sspB.

Subcellular locationi

GO - Cellular componenti

  • cytosol Source: EcoCyc
  • ribosome Source: EcoCyc
Complete GO annotation...

Pathology & Biotechi

Disruption phenotypei

Decreased degradation of ssrA-tagged proteins by ClpX-ClpP, no effect on degradation by ClpA-ClpP protease. Delayed and decreased induction of the extracytoplasmic-stress response.2 Publications

Mutagenesis

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Mutagenesisi52 – 521V → D, M or Q: No folded protein. 1 Publication
Mutagenesisi52 – 521V → I: 2.5-fold reduction in binding of RseA, no effect on ssrA-tag binding. 1 Publication
Mutagenesisi59 – 591A → T: 10-fold reduction in binding of ssrA tag and RseA. 1 Publication
Mutagenesisi74 – 741A → Q: Severe reduction in binding of ssrA tag (40-fold) and RseA (100-fold). 1 Publication

PTM / Processingi

Molecule processing

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Chaini1 – 165165Stringent starvation protein BPRO_0000072218Add
BLAST

Proteomic databases

EPDiP0AFZ3.
PaxDbiP0AFZ3.
PRIDEiP0AFZ3.

2D gel databases

SWISS-2DPAGEP0AFZ3.

Expressioni

Inductioni

By amino acid starvation.1 Publication

Interactioni

Subunit structurei

Homodimer. Binds 1 ssrA-tag per monomer; if the first Asn residue of the ssrA tag is mutated to Ala, SspB no longer binds the protein or stimulates ClpX-ClpP degradation (PubMed:11009422). Binds the N-terminus (residues 1-108) of RseA with and without sigma-E (PubMed:15371343); although ssrA and the N-terminal fragment of RseA both bind to SspB competitively they bind in opposite directions in its peptide-binding groove.5 Publications

Protein-protein interaction databases

BioGridi4262444. 74 interactions.
DIPiDIP-29563N.
IntActiP0AFZ3. 31 interactions.
MINTiMINT-1226453.
STRINGi511145.b3228.

Structurei

Secondary structure

1
165
Legend: HelixTurnBeta strand
Show more details
Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Helixi10 – 2314Combined sources
Beta strandi28 – 336Combined sources
Helixi43 – 453Combined sources
Beta strandi50 – 545Combined sources
Helixi57 – 593Combined sources
Beta strandi61 – 655Combined sources
Beta strandi67 – 7610Combined sources
Beta strandi79 – 868Combined sources
Helixi87 – 893Combined sources
Beta strandi90 – 956Combined sources
Turni96 – 983Combined sources
Beta strandi101 – 1033Combined sources
Turni108 – 1103Combined sources

3D structure databases

Select the link destinations:
PDBei
RCSB PDBi
PDBji
Links Updated
EntryMethodResolution (Å)ChainPositionsPDBsum
1OX8X-ray2.20A/B5-111[»]
1OX9X-ray2.90A/B/C/D/E/F/G/H4-111[»]
1YFNX-ray1.80A/B/C/D1-118[»]
2DS8X-ray1.60P/Q159-165[»]
DisProtiDP00194.
ProteinModelPortaliP0AFZ3.
SMRiP0AFZ3. Positions 3-111.
ModBaseiSearch...
MobiDBiSearch...

Miscellaneous databases

EvolutionaryTraceiP0AFZ3.

Family & Domainsi

Region

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Regioni73 – 9523Binds SspBAdd
BLAST
Regioni128 – 16538Required for interaction with ClpX, not required for ssrA tag recognition or dimerizationAdd
BLAST

Sequence similaritiesi

Belongs to the SspB family.Curated

Phylogenomic databases

eggNOGiENOG4105KB2. Bacteria.
COG2969. LUCA.
HOGENOMiHOG000255240.
InParanoidiP0AFZ3.
KOiK03600.
OMAiPHTLYVP.
PhylomeDBiP0AFZ3.

Family and domain databases

Gene3Di2.30.30.220. 1 hit.
InterProiIPR007481. SspB.
[Graphical view]
PfamiPF04386. SspB. 1 hit.
[Graphical view]
PIRSFiPIRSF005276. SspB. 1 hit.
SUPFAMiSSF101738. SSF101738. 1 hit.

Sequencei

Sequence statusi: Complete.

P0AFZ3-1 [UniParc]FASTAAdd to basket

« Hide

        10         20         30         40         50
MDLSQLTPRR PYLLRAFYEW LLDNQLTPHL VVDVTLPGVQ VPMEYARDGQ
60 70 80 90 100
IVLNIAPRAV GNLELANDEV RFNARFGGIP RQVSVPLAAV LAIYARENGA
110 120 130 140 150
GTMFEPEAAY DEDTSIMNDE EASADNETVM SVIDGDKPDH DDDTHPDDEP
160
PQPPRGGRPA LRVVK
Length:165
Mass (Da):18,262
Last modified:December 20, 2005 - v1
Checksum:i363ECEB430AE5A18
GO

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
M69028 Genomic DNA. Translation: AAA24650.1.
U18997 Genomic DNA. Translation: AAA58030.1.
U00096 Genomic DNA. Translation: AAC76260.1.
AP009048 Genomic DNA. Translation: BAE77271.1.
X05088 Genomic DNA. Translation: CAA28741.1.
PIRiJS0666.
RefSeqiNP_417695.1. NC_000913.3.
WP_000366129.1. NZ_LN832404.1.

Genome annotation databases

EnsemblBacteriaiAAC76260; AAC76260; b3228.
BAE77271; BAE77271; BAE77271.
GeneIDi944774.
KEGGiecj:JW3197.
eco:b3228.
PATRICi32121880. VBIEscCol129921_3324.

Cross-referencesi

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
M69028 Genomic DNA. Translation: AAA24650.1.
U18997 Genomic DNA. Translation: AAA58030.1.
U00096 Genomic DNA. Translation: AAC76260.1.
AP009048 Genomic DNA. Translation: BAE77271.1.
X05088 Genomic DNA. Translation: CAA28741.1.
PIRiJS0666.
RefSeqiNP_417695.1. NC_000913.3.
WP_000366129.1. NZ_LN832404.1.

3D structure databases

Select the link destinations:
PDBei
RCSB PDBi
PDBji
Links Updated
EntryMethodResolution (Å)ChainPositionsPDBsum
1OX8X-ray2.20A/B5-111[»]
1OX9X-ray2.90A/B/C/D/E/F/G/H4-111[»]
1YFNX-ray1.80A/B/C/D1-118[»]
2DS8X-ray1.60P/Q159-165[»]
DisProtiDP00194.
ProteinModelPortaliP0AFZ3.
SMRiP0AFZ3. Positions 3-111.
ModBaseiSearch...
MobiDBiSearch...

Protein-protein interaction databases

BioGridi4262444. 74 interactions.
DIPiDIP-29563N.
IntActiP0AFZ3. 31 interactions.
MINTiMINT-1226453.
STRINGi511145.b3228.

2D gel databases

SWISS-2DPAGEP0AFZ3.

Proteomic databases

EPDiP0AFZ3.
PaxDbiP0AFZ3.
PRIDEiP0AFZ3.

Protocols and materials databases

Structural Biology KnowledgebaseSearch...

Genome annotation databases

EnsemblBacteriaiAAC76260; AAC76260; b3228.
BAE77271; BAE77271; BAE77271.
GeneIDi944774.
KEGGiecj:JW3197.
eco:b3228.
PATRICi32121880. VBIEscCol129921_3324.

Organism-specific databases

EchoBASEiEB0971.
EcoGeneiEG10978. sspB.

Phylogenomic databases

eggNOGiENOG4105KB2. Bacteria.
COG2969. LUCA.
HOGENOMiHOG000255240.
InParanoidiP0AFZ3.
KOiK03600.
OMAiPHTLYVP.
PhylomeDBiP0AFZ3.

Enzyme and pathway databases

BioCyciEcoCyc:EG10978-MONOMER.
ECOL316407:JW3197-MONOMER.

Miscellaneous databases

EvolutionaryTraceiP0AFZ3.
PROiP0AFZ3.

Family and domain databases

Gene3Di2.30.30.220. 1 hit.
InterProiIPR007481. SspB.
[Graphical view]
PfamiPF04386. SspB. 1 hit.
[Graphical view]
PIRSFiPIRSF005276. SspB. 1 hit.
SUPFAMiSSF101738. SSF101738. 1 hit.
ProtoNetiSearch...

Entry informationi

Entry nameiSSPB_ECOLI
AccessioniPrimary (citable) accession number: P0AFZ3
Secondary accession number(s): P25663, Q2M8Y5
Entry historyi
Integrated into UniProtKB/Swiss-Prot: December 20, 2005
Last sequence update: December 20, 2005
Last modified: September 7, 2016
This is version 86 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, Direct protein sequencing, 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.