ID   VKT2K_HETCR             Reviewed;          15 AA.
AC   P0DV07;
DT   23-FEB-2022, integrated into UniProtKB/Swiss-Prot.
DT   23-FEB-2022, sequence version 1.
DT   03-AUG-2022, entry version 2.
DE   RecName: Full=PI-stichotoxin-Hcr2k {ECO:0000305};
DE            Short=PI-SHTX-Hcr2k {ECO:0000305};
DE   AltName: Full=Kunitz-type serine protease inhibitor RmIn I {ECO:0000303|PubMed:17447883};
DE   Flags: Fragment;
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, AND MASS SPECTROMETRY.
RX   PubMed=17447883; DOI=10.1134/s0006297907030078;
RA   Sokotun I.N., Il'ina A.P., Monastyrnaya M.M., Leychenko E.V., Es'kov A.A.,
RA   Anastuk S.D., Kozlovskaya E.P.;
RT   "Proteinase inhibitors from the tropical sea anemone Radianthus
RT   macrodactylus: isolation and characteristic.";
RL   Biochemistry (Mosc.) 72:301-306(2007).
CC   -!- FUNCTION: This recombinant serine protease inhibitor inhibits both
CC       trypsin (Ki=2.4 nM) and chymotrypsin (Ki=23 nM) (PubMed:17447883). It
CC       may also inhibit the TRPV1 receptor, a receptor of the pain pathway (By
CC       similarity). In vivo, shows anti-histamine activity, since it dose-
CC       dependently weakens the clinical manifestation of the allergic reaction
CC       induced by histamine injection. In vivo, does not show toxicity to mice
CC       by intraperitoneal injection (PubMed:17447883).
CC       {ECO:0000250|UniProtKB:B2G331, ECO:0000269|PubMed:17447883}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000305}. Nematocyst {ECO:0000305}.
CC   -!- MASS SPECTROMETRY: Mass=6201.6; Method=MALDI;
CC       Evidence={ECO:0000269|PubMed:17447883};
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   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.
PE   1: Evidence at protein level;
KW   Direct protein sequencing; Disulfide bond; Ion channel impairing toxin;
KW   Nematocyst; Protease inhibitor; Secreted; Serine protease inhibitor; Toxin.
FT   CHAIN           1..>15
FT                   /note="PI-stichotoxin-Hcr2k"
FT                   /id="PRO_0000454108"
FT   SITE            13..14
FT                   /note="Reactive bond for trypsin"
FT                   /evidence="ECO:0000250|UniProtKB:P00974"
FT   DISULFID        3..?
FT                   /evidence="ECO:0000305"
FT   DISULFID        12..?
FT                   /evidence="ECO:0000305"
FT   NON_TER         15
FT                   /evidence="ECO:0000305"
SQ   SEQUENCE   15 AA;  1430 MW;  DC1596692ABD1849 CRC64;
     GICSEPIVVG PCKAG