ID   VKTH7_BUNMU             Reviewed;          61 AA.
AC   Q0PL65;
DT   16-JUN-2009, integrated into UniProtKB/Swiss-Prot.
DT   05-SEP-2006, sequence version 1.
DT   25-MAY-2022, entry version 47.
DE   RecName: Full=Kunitz-type serine protease inhibitor homolog beta-bungarotoxin B5-B chain;
DE   AltName: Full=Beta-bungarotoxin B5 chain;
OS   Bungarus multicinctus (Many-banded krait).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi;
OC   Lepidosauria; Squamata; Bifurcata; Unidentata; Episquamata; Toxicofera;
OC   Serpentes; Colubroidea; Elapidae; Bungarinae; Bungarus.
OX   NCBI_TaxID=8616;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA].
RA   Ying T., Zhang J., Wu F., Zhang H., Kong J., Li Y.;
RL   Submitted (JUN-2006) to the EMBL/GenBank/DDBJ databases.
CC   -!- FUNCTION: Beta-bungarotoxins are presynaptic neurotoxins of the venom.
CC       The B chain is homologous to venom basic protease inhibitors but has no
CC       protease inhibitor activity and blocks voltage-gated potassium channels
CC       (Kv) (By similarity). {ECO:0000250}.
CC   -!- SUBUNIT: Heterodimer; disulfide-linked. The A chains have phospholipase
CC       A2 activity and the B chains show homology with the basic protease
CC       inhibitors (By similarity). {ECO:0000250}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000250}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC   -!- SIMILARITY: Belongs to the venom Kunitz-type family. {ECO:0000305}.
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DR   EMBL; DQ810294; ABG90493.1; -; mRNA.
DR   AlphaFoldDB; Q0PL65; -.
DR   SMR; Q0PL65; -.
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:InterPro.
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   2: Evidence at transcript level;
KW   Disulfide bond; Ion channel impairing toxin; Neurotoxin;
KW   Potassium channel impairing toxin; Presynaptic neurotoxin; Secreted; Toxin;
KW   Voltage-gated potassium channel impairing toxin.
FT   CHAIN           1..61
FT                   /note="Kunitz-type serine protease inhibitor homolog beta-
FT                   bungarotoxin B5-B chain"
FT                   /id="PRO_0000376877"
FT   DOMAIN          7..57
FT                   /note="BPTI/Kunitz inhibitor"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00031"
FT   DISULFID        7..57
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00031"
FT   DISULFID        16..40
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00031"
FT   DISULFID        32..53
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00031"
FT   DISULFID        55
FT                   /note="Interchain (with an A chain)"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00031"
SQ   SEQUENCE   61 AA;  7134 MW;  989F2BF3DE0844FD CRC64;
     RQRHPDCDKP PDTKRCTGHN PAFYYNPRRK NCERFSYGGC GGNGNHFKTK QLCHCHCHEN
     D