ID   TPX_STRPA               Reviewed;         164 AA.
AC   P31307;
DT   01-JUL-1993, integrated into UniProtKB/Swiss-Prot.
DT   23-JAN-2007, sequence version 3.
DT   25-MAY-2022, entry version 99.
DE   RecName: Full=Thiol peroxidase {ECO:0000255|HAMAP-Rule:MF_00269};
DE            Short=Tpx {ECO:0000255|HAMAP-Rule:MF_00269};
DE            EC=1.11.1.24 {ECO:0000255|HAMAP-Rule:MF_00269};
DE   AltName: Full=Peroxiredoxin tpx {ECO:0000255|HAMAP-Rule:MF_00269};
DE            Short=Prx {ECO:0000255|HAMAP-Rule:MF_00269};
DE   AltName: Full=Thioredoxin peroxidase {ECO:0000255|HAMAP-Rule:MF_00269};
DE   AltName: Full=Thioredoxin-dependent peroxiredoxin {ECO:0000255|HAMAP-Rule:MF_00269};
GN   Name=tpx {ECO:0000255|HAMAP-Rule:MF_00269};
OS   Streptococcus parasanguinis.
OC   Bacteria; Firmicutes; Bacilli; Lactobacillales; Streptococcaceae;
OC   Streptococcus.
OX   NCBI_TaxID=1318;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RC   STRAIN=FW213;
RX   PubMed=2572555; DOI=10.1128/iai.57.11.3527-3533.1989;
RA   Fenno J.C., Leblanc D.J., Fives-Taylor P.M.;
RT   "Nucleotide sequence analysis of a type 1 fimbrial gene of Streptococcus
RT   sanguis FW213.";
RL   Infect. Immun. 57:3527-3533(1989).
CC   -!- FUNCTION: Thiol-specific peroxidase that catalyzes the reduction of
CC       hydrogen peroxide and organic hydroperoxides to water and alcohols,
CC       respectively. Plays a role in cell protection against oxidative stress
CC       by detoxifying peroxides. {ECO:0000255|HAMAP-Rule:MF_00269}.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=[thioredoxin]-dithiol + a hydroperoxide = [thioredoxin]-
CC         disulfide + an alcohol + H2O; Xref=Rhea:RHEA:62620, Rhea:RHEA-
CC         COMP:10698, Rhea:RHEA-COMP:10700, ChEBI:CHEBI:15377,
CC         ChEBI:CHEBI:29950, ChEBI:CHEBI:30879, ChEBI:CHEBI:35924,
CC         ChEBI:CHEBI:50058; EC=1.11.1.24; Evidence={ECO:0000255|HAMAP-
CC         Rule:MF_00269};
CC   -!- SUBUNIT: Homodimer. {ECO:0000255|HAMAP-Rule:MF_00269}.
CC   -!- MISCELLANEOUS: The active site is a conserved redox-active cysteine
CC       residue, the peroxidatic cysteine (C(P)), which makes the nucleophilic
CC       attack on the peroxide substrate. The peroxide oxidizes the C(P)-SH to
CC       cysteine sulfenic acid (C(P)-SOH), which then reacts with another
CC       cysteine residue, the resolving cysteine (C(R)), to form a disulfide
CC       bridge. The disulfide is subsequently reduced by an appropriate
CC       electron donor to complete the catalytic cycle. In this atypical 2-Cys
CC       peroxiredoxin, C(R) is present in the same subunit to form an
CC       intramolecular disulfide. The disulfide is subsequently reduced by
CC       thioredoxin. {ECO:0000255|HAMAP-Rule:MF_00269}.
CC   -!- SIMILARITY: Belongs to the peroxiredoxin family. Tpx subfamily.
CC       {ECO:0000255|HAMAP-Rule:MF_00269}.
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DR   EMBL; M26130; AAA53078.1; -; Genomic_DNA.
DR   PIR; S61913; S61913.
DR   RefSeq; WP_014712824.1; NZ_LAWB01000013.1.
DR   AlphaFoldDB; P31307; -.
DR   SMR; P31307; -.
DR   GO; GO:0008379; F:thioredoxin peroxidase activity; IEA:UniProtKB-UniRule.
DR   CDD; cd03014; PRX_Atyp2cys; 1.
DR   HAMAP; MF_00269; Tpx; 1.
DR   InterPro; IPR013740; Redoxin.
DR   InterPro; IPR036249; Thioredoxin-like_sf.
DR   InterPro; IPR013766; Thioredoxin_domain.
DR   InterPro; IPR002065; TPX.
DR   InterPro; IPR018219; Tpx_CS.
DR   Pfam; PF08534; Redoxin; 1.
DR   SUPFAM; SSF52833; SSF52833; 1.
DR   PROSITE; PS51352; THIOREDOXIN_2; 1.
DR   PROSITE; PS01265; TPX; 1.
PE   3: Inferred from homology;
KW   Antioxidant; Disulfide bond; Oxidoreductase; Peroxidase;
KW   Redox-active center.
FT   INIT_MET        1
FT                   /note="Removed"
FT                   /evidence="ECO:0000250"
FT   CHAIN           2..164
FT                   /note="Thiol peroxidase"
FT                   /id="PRO_0000187912"
FT   DOMAIN          16..162
FT                   /note="Thioredoxin"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00269"
FT   ACT_SITE        58
FT                   /note="Cysteine sulfenic acid (-SOH) intermediate"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00269"
FT   DISULFID        58..92
FT                   /note="Redox-active"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00269"
SQ   SEQUENCE   164 AA;  17957 MW;  7E6B771428270BA3 CRC64;
     MATFLGNPVT FTGSQLQVGE IAHDFSLITP ALEKKSLADF AGKKKVLSII PSIDTGICSM
     QTRHFNKTLS DLEDTVVLTV SVDLPFAQGK WCAAEGLDNA IMLSDYYDHS FGKAYGLLIN
     EWHLLARAVL VLDADNKITY VEYLDNINSE PNYDAAIEAV KVLG