spx

spx
168

transcriptional regulator Spx, involved in regulation of many genes, important for the prevention of protein aggregation during severe heat stress, required for protection against paraquat stress

Locus
BSU_11500
Molecular weight
15.39 kDa
Isoelectric point
7.91
Protein length
131 aaSequenceBlast
Gene length
396 bpSequenceBlast
Function
negative and positive regulator of many genes
Product
transcriptional regulator Spx
Essential
no
Synonyms
spx, yjbD
Outlinks
BsubCyc UniProt STRING Genoscapist PaperBLAST

Genomic Context

Categories containing this gene/protein

List of homologs in different organisms, belongs to COG1393 (Galperin et al., 2021)

This gene is a member of the following regulons

Gene
Coordinates
1,227,697  1,228,092
Phenotypes of a mutant
Loss of up-regulation of the methionine sulfoxide reductase (''msrA-msrB) operon in response to thiol specific oxidative stress, also loss of trxA and trxB'' upregulation in response to thiol specific oxidative stress.
The protein
Catalyzed reaction/ biological activity
transcriptional regulator of  many genes in response to thiol specific oxidative stress (transcription activator of trxA and trxB)
in addition, Spx inhibits transcription by binding to the C-terminal domain of the alpha subunit of RNAP (RpoA), disrupting complex formation between RNAP and certain transcriptional activator proteins like ResD and ComA
in response to thiol specific oxidative stress, Spx can also activate transcription, making it a general regulator that exerts both positive and negative control over transcription initiation
involved in competence regulation PubMed
inhibits expression of translation-related genes during heat stress PubMed
Protein family
ArsC family (with MgsR and YusI, according to UniProt)
Domains
CXXC (10-13): Acts as a disulfide switch for the redox-sensitive transcriptional regulation of genes that function in thiol homeostasis.
Structure
1Z3E (PDB) (complex with C-terminal domain of RpoA) PubMed
7F75 (PDB) (complex with RNA polymerase) PubMed
6GHB (PDB) (complexed with oxidized Geobacillus kaustophilus SpxH) PubMed
7F75 (PDB) PubMed
6GHO (PDB) (complexed with Geobacillus kaustophilus SpxH) PubMed
O31602 (AlphaFold)
Modification
Cysteine oxidation of CXXC motif
phosphorylation on R14, R91, R100, R112 by McsB, dephosphosphorylation by YwlE PubMed
Paralogous protein(s)
MgsR
Localization
cytoplasm (according to UniProt)
Additional information
Spx can be degraded by ClpX-ClpP with SpxH as the adapter protein PubMed
Expression and Regulation
Operons
Genes
spx
Description
PubMed
Regulation
induced by stress (SigB) PubMed
Regulatory mechanism
PerR: repression, PubMed, in perR regulon
Sigma factors
SigW: sigma factor, four promoters upstream of YjbC, in sigW regulon
SigB: sigma factor, four promoters upstream of YjbC, in sigB regulon
SigX: sigma factor, four promoters upstream of YjbC PubMed, in sigX regulon
SigM: sigma factor, four promoters upstream of YjbC PubMed, in sigM regulon
SigA: sigma factor, four promoters upstream of YjbC, in sigA regulon
Open in new tab

spx

2025-03-22 22:55:25

Bzhu

138

38b06447336041f77a1092c8cb036c4378d78571

33C93D90C156D50EF12279955B48503D30AD5EE1

Genes
yjbC-spx
Description
PubMed
Regulation
induced by stress (SigB) PubMed
Regulatory mechanism
PerR: repression, PubMed, in perR regulon
Sigma factors
SigM: sigma factor, PubMed, in sigM regulon
SigW: sigma factor, in sigW regulon
SigB: sigma factor, in sigB regulon
SigX: sigma factor, PubMed, in sigX regulon
Open in new tab

yjbC→spx

2025-03-27 08:04:24

Bzhu

113

bcf8f246067ad69ecde2a54b9dc1dd6aa6ba9fcd

F19AD43DD12EF67D1D851CD73B4FB79A8884DD1E

Additional information
post-translational control by ClpX-ClpP: Spx naturally contains a C-terminal sequence that resembles the SsrA tag and targets the protein for degradation. PubMed
Biological materials
Mutant
MGNA-B151 (yjbD::erm), available at the NBRP B. subtilis, Japan
GPUG3 (spc), available in Ulf Gerths and Jörg Stülke's labs
GP1788 (spc), available in Jörg Stülke's lab
GP3797 (Δspx::neo) available in Jörg Stülke's lab
ORB6781 (spc), ORB6876 (tet), available in Zuber lab, also available in Jörg Stülke's lab
1A917 ( spx::spec), PubMed, available at BGSC
1A916 ( spx::tet), PubMed, available at BGSC
BKE11500 (spx::erm  trpC2) available at BGSC,  PubMed, upstream reverse: _UP1_CATTCATCTTCACTCCTCTA,  downstream forward: _UP4_TAATAGATCGTATCATCAAA
BKK11500 (spx::kan  trpC2) available at BGSC,  PubMed, upstream reverse: _UP1_CATTCATCTTCACTCCTCTA,  downstream forward: _UP4_TAATAGATCGTATCATCAAA
Two-hybrid system
B. pertussis adenylate cyclase-based bacterial two hybrid system (BACTH), available in Jörg Stülke's lab
Labs working on this gene/protein
Peter Zuber, Oregon Health and Science University, USA, Homepage
Richard Brennan, Houston, Texas, USA Homepage
References
Reviews
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Original Publications
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The Spx regulon
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Structural analysis of Spx
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2C6386E9A63F410558D168798D077DF91590F454

Page visits: 13691

Time of last update: 2025-04-04 04:53:40

Author of last update: Dennis.wicke