ID   VKT52_ANESU             Reviewed;          62 AA.
AC   P10280;
DT   01-JUL-1989, integrated into UniProtKB/Swiss-Prot.
DT   01-FEB-1991, sequence version 2.
DT   25-MAY-2022, entry version 92.
DE   RecName: Full=KappaPI-actitoxin-Avd3a {ECO:0000303|PubMed:22683676};
DE            Short=KappaPI-AITX-Avd3a {ECO:0000303|PubMed:22683676};
DE   AltName: Full=Kunitz-type proteinase inhibitor 5 II {ECO:0000303|Ref.2};
DE   AltName: Full=SA5 II {ECO:0000303|Ref.2};
OS   Anemonia sulcata (Mediterranean snakelocks sea anemone).
OC   Eukaryota; Metazoa; Cnidaria; Anthozoa; Hexacorallia; Actiniaria;
OC   Actiniidae; Anemonia.
OX   NCBI_TaxID=6108;
RN   [1]
RP   PROTEIN SEQUENCE, AND FUNCTION.
RA   Krebs H.C., Habermehl G.G.;
RT   "Isolation and structural determination of a hemolytic active peptide from
RT   the sea anemone Metridium senile.";
RL   Naturwissenschaften 74:395-396(1987).
RN   [2]
RP   PROTEIN SEQUENCE OF 1-59.
RA   Wunderer G., Machleidt W., Fritz H.;
RT   "The broad-specificity proteinase inhibitor 5 II from the sea anemone
RT   Anemonia sulcata.";
RL   Methods Enzymol. 80:816-820(1981).
RN   [3]
RP   NOMENCLATURE.
RX   PubMed=22683676; DOI=10.1016/j.toxicon.2012.05.020;
RA   Oliveira J.S., Fuentes-Silva D., King G.F.;
RT   "Development of a rational nomenclature for naming peptide and protein
RT   toxins from sea anemones.";
RL   Toxicon 60:539-550(2012).
CC   -!- FUNCTION: Serine protease inhibitor that inhibits both tissue and
CC       plasma kallikreins. Has hemolytic activity (Ref.2). Inhibits voltage-
CC       gated potassium channels (By similarity).
CC       {ECO:0000250|UniProtKB:Q9TWF8, ECO:0000269|Ref.1}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000305}. Nematocyst {ECO:0000305}.
CC   -!- SIMILARITY: Belongs to the venom Kunitz-type family. Sea anemone type 2
CC       potassium channel toxin subfamily. {ECO:0000305}.
CC   -!- CAUTION: Opinions are divided on whether Anemonia viridis (Forsskal,
CC       1775) and Anemonia sulcata (Pennant, 1777) are separate species.
CC       {ECO:0000305}.
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DR   PIR; S07451; S07451.
DR   AlphaFoldDB; P10280; -.
DR   SMR; P10280; -.
DR   MEROPS; I02.026; -.
DR   PRIDE; P10280; -.
DR   GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR   GO; GO:0042151; C:nematocyst; IEA:UniProtKB-SubCell.
DR   GO; GO:0004867; F:serine-type endopeptidase inhibitor 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; Nematocyst; Protease inhibitor;
KW   Secreted; Serine protease inhibitor.
FT   CHAIN           1..62
FT                   /note="KappaPI-actitoxin-Avd3a"
FT                   /evidence="ECO:0000269|Ref.1"
FT                   /id="PRO_0000155415"
FT   DOMAIN          5..55
FT                   /note="BPTI/Kunitz inhibitor"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00031"
FT   SITE            15..16
FT                   /note="Reactive bond"
FT                   /evidence="ECO:0000250"
FT   DISULFID        5..55
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00031"
FT   DISULFID        14..38
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00031"
FT   DISULFID        30..51
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00031"
FT   VARIANT         13
FT                   /note="P -> R"
FT   VARIANT         16
FT                   /note="A -> G"
FT   VARIANT         17
FT                   /note="R -> G"
FT   VARIANT         25
FT                   /note="S -> L"
FT   VARIANT         28
FT                   /note="K -> R"
FT   VARIANT         39
FT                   /note="G -> R"
SQ   SEQUENCE   62 AA;  6937 MW;  7262D028CA567BC8 CRC64;
     INGDCELPKV VGPCRARFPR YYYNSSSKRC EKFIYGGCGG NANNFHTLEE CEKVCGVRSV
     GR