ID   VKT31_CYRHA             Reviewed;          88 AA.
AC   P0DJ64;
DT   16-NOV-2011, integrated into UniProtKB/Swiss-Prot.
DT   16-NOV-2011, sequence version 1.
DT   03-AUG-2022, entry version 31.
DE   RecName: Full=U15-Kunitz-type theraphotoxin-Hhn1b;
DE            Short=U15-TRTX-Hhn1b;
DE   AltName: Full=Kunitz-type serine protease inhibitor HNTX-0314931 {ECO:0000303|PubMed:18923708};
DE   Flags: Precursor;
OS   Cyriopagopus hainanus (Chinese bird spider) (Haplopelma hainanum).
OC   Eukaryota; Metazoa; Ecdysozoa; Arthropoda; Chelicerata; Arachnida; Araneae;
OC   Mygalomorphae; Theraphosidae; Haplopelma.
OX   NCBI_TaxID=209901;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA].
RX   PubMed=18923708; DOI=10.1371/journal.pone.0003414;
RA   Yuan C.-H., He Q.-Y., Peng K., Diao J.-B., Jiang L.-P., Tang X.,
RA   Liang S.-P.;
RT   "Discovery of a distinct superfamily of Kunitz-type toxin (KTT) from
RT   tarantulas.";
RL   PLoS ONE 3:E3414-E3414(2008).
CC   -!- FUNCTION: Dual-function toxin that inhibits both serine proteases and
CC       voltage-gated potassium channels (Kv). {ECO:0000250}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000305|PubMed:18923708}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC       {ECO:0000305|PubMed:18923708}.
CC   -!- SIMILARITY: Belongs to the venom Kunitz-type family. 03 (sub-Kunitz)
CC       subfamily. {ECO:0000305}.
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DR   AlphaFoldDB; P0DJ64; -.
DR   SMR; P0DJ64; -.
DR   ArachnoServer; AS001598; U15-theraphotoxin-Hhn1b.
DR   GO; GO:0005576; C:extracellular region; 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   GO; GO:0044562; P:envenomation resulting in negative regulation of voltage-gated potassium channel activity in another organism; IEA:UniProt.
DR   CDD; cd00109; KU; 1.
DR   Gene3D; 4.10.410.10; -; 1.
DR   InterPro; IPR002223; Kunitz_BPTI.
DR   InterPro; IPR036880; Kunitz_BPTI_sf.
DR   Pfam; PF00014; Kunitz_BPTI; 1.
DR   PRINTS; PR00759; BASICPTASE.
DR   SMART; SM00131; KU; 1.
DR   SUPFAM; SSF57362; SSF57362; 1.
DR   PROSITE; PS50279; BPTI_KUNITZ_2; 1.
PE   3: Inferred from homology;
KW   Disulfide bond; Ion channel impairing toxin;
KW   Potassium channel impairing toxin; Protease inhibitor; Secreted;
KW   Serine protease inhibitor; Signal; Toxin;
KW   Voltage-gated potassium channel impairing toxin.
FT   SIGNAL          1..27
FT                   /evidence="ECO:0000255"
FT   PROPEP          28..33
FT                   /evidence="ECO:0000250"
FT                   /id="PRO_0000413805"
FT   CHAIN           34..88
FT                   /note="U15-Kunitz-type theraphotoxin-Hhn1b"
FT                   /id="PRO_0000413806"
FT   DOMAIN          37..85
FT                   /note="BPTI/Kunitz inhibitor"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00031"
FT   SITE            39
FT                   /note="May bind Kv1"
FT                   /evidence="ECO:0000250"
FT   SITE            47..48
FT                   /note="Reactive bond for chymotrypsin"
FT                   /evidence="ECO:0000250"
FT   DISULFID        37..85
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00031"
FT   DISULFID        60..81
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00031"
SQ   SEQUENCE   88 AA;  9859 MW;  533DAEC17975CA47 CRC64;
     MGTARFLRAV LLLSVLLMVT FPALLSAEHH DGRVDICRLP SDSGDCLRFF EMWYFDGTTC
     TKFVYGGYGG NDNRFPTEKA CVKRCAKA