ID   VKT3B_ACTEQ             Reviewed;          59 AA.
AC   P0DMW7;
DT   22-JUL-2015, integrated into UniProtKB/Swiss-Prot.
DT   22-JUL-2015, sequence version 1.
DT   25-MAY-2022, entry version 13.
DE   RecName: Full=PI-actitoxin-Aeq3b {ECO:0000303|PubMed:22683676};
DE            Short=PI-AITX-Aeq3b {ECO:0000303|PubMed:22683676};
DE   AltName: Full=Kunitz-type proteinase inhibitor AEPI-II {ECO:0000303|Ref.1};
OS   Actinia equina (Beadlet anemone).
OC   Eukaryota; Metazoa; Cnidaria; Anthozoa; Hexacorallia; Actiniaria;
OC   Actiniidae; Actinia.
OX   NCBI_TaxID=6106;
RN   [1]
RP   PROTEIN SEQUENCE.
RA   Ishida M., Minagawa S., Miyauchi K., Shimakura K., Nagashima Y., Shiomi K.;
RT   "Amino acid sequences of Kunitz-type protease inhibitors from the sea
RT   anemone Actinia equina.";
RL   Fish. Sci. 63:794-798(1997).
RN   [2]
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: Dual-function toxin that inhibits both the serine protease
CC       trypsin and voltage-gated potassium channels (Kv).
CC       {ECO:0000250|UniProtKB:B1B5I8}.
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}.
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DR   AlphaFoldDB; P0DMW7; -.
DR   SMR; P0DMW7; -.
DR   GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR   GO; GO:0042151; C:nematocyst; IEA:UniProtKB-SubCell.
DR   GO; GO:0015459; F:potassium 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; Potassium channel impairing toxin; Protease inhibitor;
KW   Secreted; Serine protease inhibitor; Toxin.
FT   CHAIN           1..59
FT                   /note="PI-actitoxin-Aeq3b"
FT                   /id="PRO_0000433571"
FT   DOMAIN          6..56
FT                   /note="BPTI/Kunitz inhibitor"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00031"
FT   DISULFID        6..56
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00031"
FT   DISULFID        15..39
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00031"
FT   DISULFID        31..52
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00031"
SQ   SEQUENCE   59 AA;  6605 MW;  58BCCFDB5EA63466 CRC64;
     DASSFCQLPA VVGKCRGYFP RFYYNTEAGK CQQFIYGGCG GNRNNFETVE DCRATCHSH