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Protein

Thiol peroxidase

Gene

tpx

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

Functioni

Thiol-specific peroxidase that catalyzes the reduction of hydrogen peroxide and organic hydroperoxides to water and alcohols, respectively. Plays a role in cell protection against oxidative stress by detoxifying peroxides. Has a preference for alkyl hydroperoxides and acts as lipid peroxidase to inhibit bacterial membrane oxidation. Acts as principal antioxidant during anaerobic growth.UniRule annotation2 Publications

Miscellaneous

The active site is a conserved redox-active cysteine residue, the peroxidatic cysteine (C(P)), which makes the nucleophilic attack on the peroxide substrate. The peroxide oxidizes the C(P)-SH to cysteine sulfenic acid (C(P)-SOH), which then reacts with another cysteine residue, the resolving cysteine (C(R)), to form a disulfide bridge. The disulfide is subsequently reduced by an appropriate electron donor to complete the catalytic cycle. In this atypical 2-Cys peroxiredoxin, C(R) is present in the same subunit to form an intramolecular disulfide. The disulfide is subsequently reduced by thioredoxin.UniRule annotation1 Publication

Catalytic activityi

2 R'-SH + ROOH = R'-S-S-R' + H2O + ROH.UniRule annotation1 Publication

Kineticsi

kcat is 76.0 sec(-1) with H2O2 as substrate and 70.1 sec(-1) with cumene hydroperoxide as substrate.1 Publication
  1. KM=1730 µM for H2O21 Publication
  2. KM=9.1 µM for cumene hydroperoxide1 Publication
  3. KM=25.5 µM for Trx1 (using H2O2 as substrate)1 Publication
  4. KM=22.5 µM for Trx1 (using cumene hydroperoxide as substrate)1 Publication

    Sites

    Feature keyPosition(s)DescriptionActionsGraphical viewLength
    Active sitei61Cysteine sulfenic acid (-SOH) intermediateUniRule annotation1 Publication1

    GO - Molecular functioni

    • hydroperoxide reductase activity Source: EcoCyc
    • thioredoxin peroxidase activity Source: EcoCyc

    GO - Biological processi

    • cell redox homeostasis Source: InterPro
    • cellular response to oxidative stress Source: EcoCyc

    Keywordsi

    Molecular functionAntioxidant, Oxidoreductase, Peroxidase

    Enzyme and pathway databases

    BioCyciEcoCyc:G6660-MONOMER
    MetaCyc:G6660-MONOMER
    BRENDAi1.11.1.7 2026

    Protein family/group databases

    PeroxiBasei6007 EcoTPx

    Names & Taxonomyi

    Protein namesi
    Recommended name:
    Thiol peroxidase1 PublicationUniRule annotation (EC:1.11.1.15UniRule annotation1 Publication)
    Short name:
    TpxUniRule annotation
    Alternative name(s):
    Peroxiredoxin tpxUniRule annotation
    Short name:
    PrxUniRule annotation
    Scavengase p201 Publication
    Thioredoxin peroxidaseUniRule annotation
    Gene namesi
    Name:tpxUniRule annotation
    Synonyms:yzzJ
    Ordered Locus Names:b1324, JW1317
    OrganismiEscherichia coli (strain K12)
    Taxonomic identifieri83333 [NCBI]
    Taxonomic lineageiBacteriaProteobacteriaGammaproteobacteriaEnterobacteralesEnterobacteriaceaeEscherichia
    Proteomesi
    • UP000000318 Componenti: Chromosome
    • UP000000625 Componenti: Chromosome

    Organism-specific databases

    EcoGeneiEG12672 tpx

    Subcellular locationi

    • Periplasm 1 Publication
    • Cytoplasm 1 Publication
    • Note: Forms a mixed disulfide with cytoplasmic thioredoxin (trx1).1 Publication

    GO - Cellular componenti

    • cytoplasm Source: EcoCyc
    • cytosol Source: EcoCyc
    • periplasmic space Source: UniProtKB-SubCell

    Keywords - Cellular componenti

    Cytoplasm, Periplasm

    Pathology & Biotechi

    Mutagenesis

    Feature keyPosition(s)DescriptionActionsGraphical viewLength
    Mutagenesisi61C → S: Abolishes catalytic activity. 1 Publication1
    Mutagenesisi82C → S: Reduces catalytic activity by 28%. 1 Publication1
    Mutagenesisi95C → S: Reduces catalytic activity by 80%. 1 Publication1

    PTM / Processingi

    Molecule processing

    Feature keyPosition(s)DescriptionActionsGraphical viewLength
    Initiator methionineiRemoved2 Publications
    ChainiPRO_00001878772 – 168Thiol peroxidaseAdd BLAST167

    Amino acid modifications

    Feature keyPosition(s)DescriptionActionsGraphical viewLength
    Disulfide bondi61 ↔ 95Redox-activeUniRule annotationCombined sources2 Publications

    Keywords - PTMi

    Disulfide bond

    Proteomic databases

    EPDiP0A862
    PaxDbiP0A862
    PRIDEiP0A862

    2D gel databases

    SWISS-2DPAGEiP0A862

    Interactioni

    Subunit structurei

    Homodimer.UniRule annotation1 Publication

    Binary interactionsi

    WithEntry#Exp.IntActNotes
    ycfPP0A8E13EBI-369411,EBI-9129402

    Protein-protein interaction databases

    BioGridi4260151, 139 interactors
    850247, 1 interactor
    DIPiDIP-31857N
    IntActiP0A862, 9 interactors
    STRINGi316385.ECDH10B_1443

    Structurei

    Secondary structure

    1168
    Legend: HelixTurnBeta strandPDB Structure known for this area
    Show more details
    Feature keyPosition(s)DescriptionActionsGraphical viewLength
    Beta strandi3 – 7Combined sources5
    Beta strandi10 – 14Combined sources5
    Beta strandi29 – 31Combined sources3
    Beta strandi37 – 39Combined sources3
    Helixi40 – 43Combined sources4
    Beta strandi46 – 52Combined sources7
    Beta strandi56 – 59Combined sources4
    Helixi61 – 71Combined sources11
    Helixi72 – 74Combined sources3
    Beta strandi75 – 86Combined sources12
    Helixi88 – 98Combined sources11
    Beta strandi102 – 107Combined sources6
    Helixi112 – 117Combined sources6
    Turni126 – 129Combined sources4
    Beta strandi133 – 138Combined sources6
    Beta strandi142 – 149Combined sources8
    Helixi159 – 164Combined sources6

    3D structure databases

    Select the link destinations:
    PDBei
    RCSB PDBi
    PDBji
    Links Updated
    PDB entryMethodResolution (Å)ChainPositionsPDBsum
    1QXHX-ray2.20A/B2-168[»]
    3HVSX-ray1.80A/B2-168[»]
    3HVVX-ray1.75A2-168[»]
    3HVXX-ray2.12A/B/C/D2-168[»]
    3I43X-ray2.80A/B2-168[»]
    4AF2X-ray1.97A1-168[»]
    ProteinModelPortaliP0A862
    SMRiP0A862
    ModBaseiSearch...
    MobiDBiSearch...

    Miscellaneous databases

    EvolutionaryTraceiP0A862

    Family & Domainsi

    Domains and Repeats

    Feature keyPosition(s)DescriptionActionsGraphical viewLength
    Domaini19 – 168ThioredoxinUniRule annotationAdd BLAST150

    Sequence similaritiesi

    Belongs to the peroxiredoxin family. Tpx subfamily.UniRule annotationCurated

    Keywords - Domaini

    Redox-active center

    Phylogenomic databases

    eggNOGiENOG4108V1J Bacteria
    COG2077 LUCA
    HOGENOMiHOG000022345
    InParanoidiP0A862
    KOiK11065
    OMAiITQEPNY
    PhylomeDBiP0A862

    Family and domain databases

    CDDicd03014 PRX_Atyp2cys, 1 hit
    HAMAPiMF_00269 Tpx, 1 hit
    InterProiView protein in InterPro
    IPR013740 Redoxin
    IPR036249 Thioredoxin-like_sf
    IPR013766 Thioredoxin_domain
    IPR002065 TPX
    IPR018219 Tpx_CS
    PfamiView protein in Pfam
    PF08534 Redoxin, 1 hit
    SUPFAMiSSF52833 SSF52833, 1 hit
    PROSITEiView protein in PROSITE
    PS51352 THIOREDOXIN_2, 1 hit
    PS01265 TPX, 1 hit

    Sequencei

    Sequence statusi: Complete.

    Sequence processingi: The displayed sequence is further processed into a mature form.

    P0A862-1 [UniParc]FASTAAdd to basket

    « Hide

            10         20         30         40         50
    MSQTVHFQGN PVTVANSIPQ AGSKAQTFTL VAKDLSDVTL GQFAGKRKVL
    60 70 80 90 100
    NIFPSIDTGV CAASVRKFNQ LATEIDNTVV LCISADLPFA QSRFCGAEGL
    110 120 130 140 150
    NNVITLSTFR NAEFLQAYGV AIADGPLKGL AARAVVVIDE NDNVIFSQLV
    160
    DEITTEPDYE AALAVLKA
    Length:168
    Mass (Da):17,835
    Last modified:January 23, 2007 - v2
    Checksum:iF95F39094A07DBB2
    GO

    Experimental Info

    Feature keyPosition(s)DescriptionActionsGraphical viewLength
    Sequence conflicti61C → Y in AAC43517 (PubMed:7499381).Curated1

    Sequence databases

    Select the link destinations:
    EMBLi
    GenBanki
    DDBJi
    Links Updated
    U33213 Genomic DNA Translation: AAC43517.1
    U93212 Genomic DNA Translation: AAC45284.1
    U00096 Genomic DNA Translation: AAC74406.1
    AP009048 Genomic DNA Translation: BAA14906.1
    PIRiJC5504
    RefSeqiNP_415840.1, NC_000913.3
    WP_000084387.1, NZ_LN832404.1

    Genome annotation databases

    EnsemblBacteriaiAAC74406; AAC74406; b1324
    BAA14906; BAA14906; BAA14906
    GeneIDi945880
    KEGGiecj:JW1317
    eco:b1324
    PATRICifig|1411691.4.peg.954

    Similar proteinsi

    Entry informationi

    Entry nameiTPX_ECOLI
    AccessioniPrimary (citable) accession number: P0A862
    Secondary accession number(s): P37901
    , P57669, P76047, P77786
    Entry historyiIntegrated into UniProtKB/Swiss-Prot: June 7, 2005
    Last sequence update: January 23, 2007
    Last modified: March 28, 2018
    This is version 119 of the entry and version 2 of the sequence. See 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

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