ID   VKT18_DRYCN             Reviewed;          83 AA.
AC   F8J2F6;
DT   19-FEB-2014, integrated into UniProtKB/Swiss-Prot.
DT   21-SEP-2011, sequence version 1.
DT   25-MAY-2022, entry version 24.
DE   RecName: Full=Kunitz-type serine protease inhibitor 18;
DE            Short=SPI-18;
DE   Flags: Precursor;
OS   Drysdalia coronoides (White-lipped snake) (Hoplocephalus coronoides).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi;
OC   Lepidosauria; Squamata; Bifurcata; Unidentata; Episquamata; Toxicofera;
OC   Serpentes; Colubroidea; Elapidae; Notechinae; Drysdalia.
OX   NCBI_TaxID=66186;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA], AND IDENTIFICATION BY MASS SPECTROMETRY.
RC   TISSUE=Venom, and Venom gland;
RX   PubMed=21133350; DOI=10.1021/pr1008916;
RA   Chatrath S.T., Chapeaurouge A., Lin Q., Lim T.K., Dunstan N., Mirtschin P.,
RA   Kumar P.P., Kini R.M.;
RT   "Identification of novel proteins from the venom of a cryptic snake
RT   Drysdalia coronoides by a combined transcriptomics and proteomics
RT   approach.";
RL   J. Proteome Res. 10:739-750(2011).
CC   -!- FUNCTION: Serine protease inhibitor. {ECO:0000250}.
CC   -!- SUBCELLULAR LOCATION: Secreted.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC   -!- SIMILARITY: Belongs to the venom Kunitz-type family. {ECO:0000305}.
CC   -!- CAUTION: The P1 reactive site residue Lys-41 is replaced by Asn-41. The
CC       impact of this replacement on the protease inhibition has not yet been
CC       determined. {ECO:0000305}.
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DR   EMBL; FJ752474; ACR78496.1; -; mRNA.
DR   AlphaFoldDB; F8J2F6; -.
DR   SMR; F8J2F6; -.
DR   GO; GO:0005576; C:extracellular region; 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   Disulfide bond; Protease inhibitor; Secreted; Serine protease inhibitor;
KW   Signal.
FT   SIGNAL          1..24
FT                   /evidence="ECO:0000255"
FT   CHAIN           25..83
FT                   /note="Kunitz-type serine protease inhibitor 18"
FT                   /id="PRO_0000425516"
FT   DOMAIN          31..81
FT                   /note="BPTI/Kunitz inhibitor"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00031"
FT   SITE            41..42
FT                   /note="Reactive bond for chymotrypsin"
FT                   /evidence="ECO:0000250"
FT   DISULFID        31..81
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00031"
FT   DISULFID        40..64
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00031"
FT   DISULFID        56..77
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00031"
SQ   SEQUENCE   83 AA;  9209 MW;  993BBC15C3C7D6AC CRC64;
     MSSGGLLLLL GLLTLWEVLT PVSSKDRPHF CHLPADPGRC NALSEAFYYN PVQRKCLKFR
     YGGCKANANT FKTIDECKRT CAA