ID   VKT2C_HETCR             Reviewed;          56 AA.
AC   C0HJF4;
DT   11-DEC-2013, integrated into UniProtKB/Swiss-Prot.
DT   11-DEC-2013, sequence version 1.
DT   25-MAY-2022, entry version 22.
DE   RecName: Full=TauPI-stichotoxin-Hcr2c {ECO:0000305};
DE            Short=TauPI-SHTX-Hcr2c {ECO:0000305};
DE   AltName: Full=Analgesic polypeptide HC2 {ECO:0000303|PubMed:20208578};
DE            Short=APHC2 {ECO:0000303|PubMed:20208578};
OS   Heteractis crispa (Leathery sea anemone) (Radianthus macrodactylus).
OC   Eukaryota; Metazoa; Cnidaria; Anthozoa; Hexacorallia; Actiniaria;
OC   Stichodactylidae; Heteractis.
OX   NCBI_TaxID=175771;
RN   [1]
RP   PROTEIN SEQUENCE, FUNCTION, SUBCELLULAR LOCATION, AND MASS SPECTROMETRY.
RC   TISSUE=Nematoblast;
RX   PubMed=20208578; DOI=10.1134/s1068162009060065;
RA   Kozlov S.A., Andreev Y.A., Murashev A.N., Skobtsov D.I., D'iachenko I.A.,
RA   Grishin E.V.;
RT   "New polypeptide components from the Heteractis crispa sea anemone with
RT   analgesic activity.";
RL   Bioorg. Khim. 35:789-798(2009).
RN   [2]
RP   FUNCTION.
RA   Andreev Y.A., Mosharova I.V., Kozlov S.A., Korolkova Y.V., Grishin E.V.;
RT   "Sea anemone peptides modulate TRPV1 activity and produce analgesia without
RT   hyperthermic effect.";
RL   Submitted (OCT-2013) to UniProtKB.
CC   -!- FUNCTION: This protease inhibitor shows two different activities, it
CC       inhibits both the capsaicin receptor TRPV1 and serine proteases. It
CC       partially (max 50%) and reversibly inhibits mammalian TRPV1, a non-
CC       selective cation channel expressed by sensory neurons of the pain
CC       pathway (Ref.2 (By similarity)). The second activity is a weak
CC       inhibition of trypsin and chymotrypsin activity (Ki=0.9 uM and Ki=4.5
CC       uM, respectively) (PubMed:20208578). In vivo, shows analgesic effects
CC       on mammals (PubMed:20208578). {ECO:0000250|UniProtKB:B2G331,
CC       ECO:0000269|PubMed:20208578, ECO:0000269|Ref.2}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000269|PubMed:20208578}.
CC       Nematocyst {ECO:0000269|PubMed:20208578}.
CC   -!- MASS SPECTROMETRY: Mass=6185; Method=MALDI;
CC       Evidence={ECO:0000269|PubMed:20208578};
CC   -!- MISCELLANEOUS: Intravenous doses (up to 1 mg/kg) has no toxic effect
CC       and generated no behavioral disorders in mice.
CC       {ECO:0000269|PubMed:20208578}.
CC   -!- SIMILARITY: Belongs to the venom Kunitz-type family. Sea anemone type 2
CC       potassium channel toxin subfamily. {ECO:0000305}.
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DR   AlphaFoldDB; C0HJF4; -.
DR   SMR; C0HJF4; -.
DR   GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR   GO; GO:0042151; C:nematocyst; IEA:UniProtKB-SubCell.
DR   GO; GO:0099106; F:ion channel regulator activity; IEA:UniProtKB-KW.
DR   GO; GO:0004867; F:serine-type endopeptidase inhibitor activity; IEA:UniProtKB-KW.
DR   GO; GO:0090729; F:toxin activity; IEA:UniProtKB-KW.
DR   CDD; cd00109; KU; 1.
DR   Gene3D; 4.10.410.10; -; 1.
DR   InterPro; IPR002223; Kunitz_BPTI.
DR   InterPro; IPR036880; Kunitz_BPTI_sf.
DR   InterPro; IPR020901; Prtase_inh_Kunz-CS.
DR   Pfam; PF00014; Kunitz_BPTI; 1.
DR   PRINTS; PR00759; BASICPTASE.
DR   SMART; SM00131; KU; 1.
DR   SUPFAM; SSF57362; SSF57362; 1.
DR   PROSITE; PS00280; BPTI_KUNITZ_1; 1.
DR   PROSITE; PS50279; BPTI_KUNITZ_2; 1.
PE   1: Evidence at protein level;
KW   Direct protein sequencing; Disulfide bond; Ion channel impairing toxin;
KW   Nematocyst; Neurotoxin; Protease inhibitor; Secreted;
KW   Serine protease inhibitor; Toxin.
FT   CHAIN           1..56
FT                   /note="TauPI-stichotoxin-Hcr2c"
FT                   /evidence="ECO:0000269|PubMed:20208578"
FT                   /id="PRO_0000424699"
FT   DOMAIN          4..54
FT                   /note="BPTI/Kunitz inhibitor"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00031"
FT   SITE            14..15
FT                   /note="Reactive bond for trypsin"
FT                   /evidence="ECO:0000250|UniProtKB:P31713"
FT   DISULFID        4..54
FT                   /evidence="ECO:0000250|UniProtKB:P31713"
FT   DISULFID        13..37
FT                   /evidence="ECO:0000250|UniProtKB:P31713"
FT   DISULFID        29..50
FT                   /evidence="ECO:0000250|UniProtKB:P31713"
SQ   SEQUENCE   56 AA;  6191 MW;  342F5583272C280C CRC64;
     GSICLEPKVV GPCTAYFRRF YFDSETGKCT PFIYGGCEGN GNNFETLRAC RAICRA