ID   3L2B_PSETE              Reviewed;          71 AA.
AC   P13495;
DT   01-JAN-1990, integrated into UniProtKB/Swiss-Prot.
DT   01-JAN-1990, sequence version 1.
DT   25-MAY-2022, entry version 92.
DE   RecName: Full=Pseudonajatoxin b;
DE   AltName: Full=Long neurotoxin B;
OS   Pseudonaja textilis (Eastern brown snake).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi;
OC   Lepidosauria; Squamata; Bifurcata; Unidentata; Episquamata; Toxicofera;
OC   Serpentes; Colubroidea; Elapidae; Acanthophiinae; Pseudonaja.
OX   NCBI_TaxID=8673;
RN   [1]
RP   PROTEIN SEQUENCE, TOXIC DOSE, AND SUBCELLULAR LOCATION.
RC   TISSUE=Venom;
RX   PubMed=3595609; DOI=10.1111/j.1432-1033.1987.tb13493.x;
RA   Tyler M.I., Spence I., Barnett D., Howden M.E.H.;
RT   "Pseudonajatoxin b: unusual amino acid sequence of a lethal neurotoxin from
RT   the venom of the Australian common brown snake, Pseudonaja textilis.";
RL   Eur. J. Biochem. 166:139-143(1987).
RN   [2]
RP   PARTIAL PROTEIN SEQUENCE.
RC   TISSUE=Venom;
RX   PubMed=16284125; DOI=10.1074/mcp.m500270-mcp200;
RA   Birrell G.W., Earl S., Masci P.P., de Jersey J., Wallis T.P., Gorman J.J.,
RA   Lavin M.F.;
RT   "Molecular diversity in venom from the Australian Brown snake, Pseudonaja
RT   textilis.";
RL   Mol. Cell. Proteomics 5:379-389(2006).
CC   -!- FUNCTION: Binds with high affinity to muscular (alpha-1/CHRNA1) and
CC       neuronal (alpha-7/CHRNA7) nicotinic acetylcholine receptor (nAChR) and
CC       inhibits acetylcholine from binding to the receptor, thereby impairing
CC       neuromuscular and neuronal transmission.
CC       {ECO:0000250|UniProtKB:P60615}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000269|PubMed:3595609}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland. {ECO:0000305}.
CC   -!- TOXIC DOSE: LD(50) is 0.015 mg/kg by intraperitoneal injection into
CC       mice. {ECO:0000269|PubMed:3595609}.
CC   -!- SIMILARITY: Belongs to the snake three-finger toxin family. Long-chain
CC       subfamily. Type II alpha-neurotoxin sub-subfamily. {ECO:0000305}.
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DR   PIR; S00035; S00035.
DR   AlphaFoldDB; P13495; -.
DR   SMR; P13495; -.
DR   Proteomes; UP000472273; Unplaced.
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   CDD; cd00206; snake_toxin; 1.
DR   Gene3D; 2.10.60.10; -; 1.
DR   InterPro; IPR003571; Snake_3FTx.
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   1: Evidence at protein level;
KW   Acetylcholine receptor inhibiting toxin; Direct protein sequencing;
KW   Disulfide bond; Ion channel impairing toxin; Neurotoxin;
KW   Postsynaptic neurotoxin; Reference proteome; Secreted; Toxin.
FT   CHAIN           1..71
FT                   /note="Pseudonajatoxin b"
FT                   /id="PRO_0000093563"
FT   DISULFID        3..21
FT                   /evidence="ECO:0000250"
FT   DISULFID        14..42
FT                   /evidence="ECO:0000250"
FT   DISULFID        27..31
FT                   /evidence="ECO:0000250"
FT   DISULFID        46..58
FT                   /evidence="ECO:0000250"
FT   DISULFID        59..64
FT                   /evidence="ECO:0000250"
FT   CONFLICT        3
FT                   /note="C -> E (in Ref. 2; AA sequence)"
FT                   /evidence="ECO:0000305"
SQ   SEQUENCE   71 AA;  7761 MW;  EC14D31E33CF4315 CRC64;
     RTCFITPDVK SKPCPPGQEV CYTETWCDGF CGIRGKRVEL GCAATCPTPK KTGIDIQCCS
     TDDCNTFPLR P