ID   YCF42_PORPU             Reviewed;         199 AA.
AC   P51272;
DT   01-OCT-1996, integrated into UniProtKB/Swiss-Prot.
DT   01-OCT-1996, sequence version 1.
DT   25-MAY-2022, entry version 85.
DE   RecName: Full=Putative peroxiredoxin ycf42;
DE            EC=1.11.1.24 {ECO:0000250|UniProtKB:Q06830};
DE   AltName: Full=Thioredoxin peroxidase;
GN   Name=ycf42;
OS   Porphyra purpurea (Red seaweed) (Ulva purpurea).
OG   Plastid; Chloroplast.
OC   Eukaryota; Rhodophyta; Bangiophyceae; Bangiales; Bangiaceae; Porphyra.
OX   NCBI_TaxID=2787;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=Avonport;
RA   Reith M.E., Munholland J.;
RT   "Complete nucleotide sequence of the Porphyra purpurea chloroplast
RT   genome.";
RL   Plant Mol. Biol. Rep. 13:333-335(1995).
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:0000250|UniProtKB:Q06830}.
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;
CC         Evidence={ECO:0000250|UniProtKB:Q06830};
CC   -!- SUBUNIT: Homodimer; disulfide-linked, upon oxidation.
CC       {ECO:0000250|UniProtKB:Q06830}.
CC   -!- SUBCELLULAR LOCATION: Plastid, chloroplast {ECO:0000305}.
CC   -!- PTM: The Cys-53-SH group is the primary site of oxidation by H(2)O(2),
CC       and the oxidized Cys-53 (probably Cys-SOH) rapidly reacts with Cys-174-
CC       SH of the other subunit to form an intermolecular disulfide. This
CC       disulfide is subsequently reduced by thioredoxin (By similarity).
CC       {ECO:0000250}.
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 typical 2-Cys
CC       peroxiredoxin, C(R) is provided by the other dimeric subunit to form an
CC       intersubunit disulfide. The disulfide is subsequently reduced by
CC       thioredoxin. {ECO:0000250|UniProtKB:Q06830}.
CC   -!- SIMILARITY: Belongs to the peroxiredoxin family. AhpC/Prx1 subfamily.
CC       {ECO:0000305}.
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DR   EMBL; U38804; AAC08158.1; -; Genomic_DNA.
DR   PIR; S73193; S73193.
DR   RefSeq; NP_053882.1; NC_000925.1.
DR   AlphaFoldDB; P51272; -.
DR   SMR; P51272; -.
DR   GeneID; 809901; -.
DR   GO; GO:0009507; C:chloroplast; IEA:UniProtKB-SubCell.
DR   GO; GO:0004601; F:peroxidase activity; IEA:UniProtKB-KW.
DR   GO; GO:0051920; F:peroxiredoxin activity; IEA:UniProtKB-EC.
DR   InterPro; IPR000866; AhpC/TSA.
DR   InterPro; IPR024706; Peroxiredoxin_AhpC-typ.
DR   InterPro; IPR019479; Peroxiredoxin_C.
DR   InterPro; IPR036249; Thioredoxin-like_sf.
DR   InterPro; IPR013766; Thioredoxin_domain.
DR   Pfam; PF10417; 1-cysPrx_C; 1.
DR   Pfam; PF00578; AhpC-TSA; 1.
DR   PIRSF; PIRSF000239; AHPC; 1.
DR   SUPFAM; SSF52833; SSF52833; 1.
DR   PROSITE; PS51352; THIOREDOXIN_2; 1.
PE   3: Inferred from homology;
KW   Antioxidant; Chloroplast; Disulfide bond; Oxidoreductase; Peroxidase;
KW   Plastid; Redox-active center.
FT   CHAIN           1..199
FT                   /note="Putative peroxiredoxin ycf42"
FT                   /id="PRO_0000135147"
FT   DOMAIN          8..165
FT                   /note="Thioredoxin"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00691"
FT   ACT_SITE        53
FT                   /note="Cysteine sulfenic acid (-SOH) intermediate"
FT                   /evidence="ECO:0000250|UniProtKB:Q06830"
FT   DISULFID        53
FT                   /note="Interchain (with C-174); in linked form"
FT                   /evidence="ECO:0000250|UniProtKB:Q06830"
FT   DISULFID        174
FT                   /note="Interchain (with C-53); in linked form"
FT                   /evidence="ECO:0000250|UniProtKB:Q06830"
SQ   SEQUENCE   199 AA;  22282 MW;  3206EDEE76920CF7 CRC64;
     MISGHNCLQV GQIAPDFSAT AVYDQEFKTI KLSDFKNKYV ILFFYPLDFT FVCPTEITAF
     SDKYSDFSEL NTEILGVSVD SEYSHLAWLQ TDRESGGLGD LEYPLVSDLK KEISIAYNVL
     NSGGVALRGL FIIDPKGIIQ YSTVNNLEFG RSVEETLRVL QAIQYVQAHP DEVCPANWKP
     GDRTMNPDPI KSKNYFAAA