ID   3NB3_TRIBI              Reviewed;         111 AA.
AC   A7X3S2;
DT   15-JAN-2008, integrated into UniProtKB/Swiss-Prot.
DT   23-OCT-2007, sequence version 1.
DT   25-MAY-2022, entry version 49.
DE   RecName: Full=Toxin 3FTx-Tri3 {ECO:0000312|EMBL:ABU68478.1};
DE   Flags: Precursor;
OS   Trimorphodon biscutatus (Western lyre snake).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi;
OC   Lepidosauria; Squamata; Bifurcata; Unidentata; Episquamata; Toxicofera;
OC   Serpentes; Colubroidea; Colubridae; Colubrinae; Trimorphodon.
OX   NCBI_TaxID=338818;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA].
RC   TISSUE=Venom gland;
RX   PubMed=17855442; DOI=10.1074/mcp.m700094-mcp200;
RA   Fry B.G., Scheib H., van der Weerd L., Young B., McNaughtan J.,
RA   Ramjan S.F.R., Vidal N., Poelmann R.E., Norman J.A.;
RT   "Evolution of an arsenal: structural and functional diversification of the
RT   venom system in the advanced snakes (Caenophidia).";
RL   Mol. Cell. Proteomics 7:215-246(2008).
CC   -!- FUNCTION: Potent postsynaptic neurotoxin. Displays readily reversible
CC       competitive antagonism at the nicotinic acetylcholine receptor (nAChR).
CC       {ECO:0000250}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000305|PubMed:17855442}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC       {ECO:0000305|PubMed:17855442}.
CC   -!- SIMILARITY: Belongs to the snake three-finger toxin family. Ancestral
CC       subfamily. Boigatoxin sub-subfamily. {ECO:0000305}.
CC   -!- CAUTION: 2 Cys residues are missing that are conventionnally part of
CC       disulfide bonds II and III. {ECO:0000305}.
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DR   EMBL; EU029678; ABU68478.1; -; mRNA.
DR   AlphaFoldDB; A7X3S2; -.
DR   SMR; A7X3S2; -.
DR   GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR   GO; GO:0030550; F:acetylcholine receptor inhibitor activity; IEA:UniProtKB-KW.
DR   GO; GO:0099106; F:ion channel regulator activity; IEA:UniProtKB-KW.
DR   GO; GO:0090729; F:toxin activity; IEA:UniProtKB-KW.
DR   Gene3D; 2.10.60.10; -; 1.
DR   InterPro; IPR045860; Snake_toxin-like_sf.
DR   InterPro; IPR018354; Snake_toxin_con_site.
DR   SUPFAM; SSF57302; SSF57302; 1.
DR   PROSITE; PS00272; SNAKE_TOXIN; 1.
PE   3: Inferred from homology;
KW   Acetylcholine receptor inhibiting toxin; Disulfide bond;
KW   Ion channel impairing toxin; Neurotoxin; Postsynaptic neurotoxin;
KW   Pyrrolidone carboxylic acid; Secreted; Signal; Toxin.
FT   SIGNAL          1..19
FT                   /evidence="ECO:0000255"
FT   PROPEP          20..34
FT                   /evidence="ECO:0000250"
FT                   /id="PRO_0000316191"
FT   CHAIN           35..111
FT                   /note="Toxin 3FTx-Tri3"
FT                   /id="PRO_0000316192"
FT   MOD_RES         35
FT                   /note="Pyrrolidone carboxylic acid"
FT                   /evidence="ECO:0000250"
FT   DISULFID        44..68
FT                   /evidence="ECO:0000250|UniProtKB:P81782"
FT   DISULFID        47..87
FT                   /evidence="ECO:0000305"
FT   DISULFID        91..102
FT                   /evidence="ECO:0000250|UniProtKB:P81782"
FT   DISULFID        103..108
FT                   /evidence="ECO:0000250|UniProtKB:P81782"
SQ   SEQUENCE   111 AA;  11931 MW;  29F22B184BB7F1DF CRC64;
     MKTLLLALVV VAFMCLGSAD EVGLGNEQID RGRRQAIGPP FTRCSKCNRN WSPPFPLGLY
     TVSHVKSCGG HLSSIGQCGE DWVVKGCAKT CPTAGPGERV KCCYSPRCNK N