ID   3L21_HYDHA              Reviewed;          92 AA.
AC   Q8UW29;
DT   15-JAN-2008, integrated into UniProtKB/Swiss-Prot.
DT   01-MAR-2002, sequence version 1.
DT   25-MAY-2022, entry version 67.
DE   RecName: Full=Long neurotoxin 1;
DE   Flags: Precursor;
OS   Hydrophis hardwickii (Hardwick's spine-bellied seasnake) (Lapemis
OS   hardwickii).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi;
OC   Lepidosauria; Squamata; Bifurcata; Unidentata; Episquamata; Toxicofera;
OC   Serpentes; Colubroidea; Hydrophiidae; Hydrophis.
OX   NCBI_TaxID=8781;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA].
RC   TISSUE=Venom gland;
RA   Wei J.W., Zhao G., Zhong X.F., Yang W., Xu A.L.;
RT   "A novel long neurotoxin isoform.";
RL   Submitted (JUN-1999) to the EMBL/GenBank/DDBJ databases.
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:0000250}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland. {ECO:0000305}.
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   EMBL; AF159537; AAL54892.1; -; mRNA.
DR   AlphaFoldDB; Q8UW29; -.
DR   SMR; Q8UW29; -.
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   3: Inferred from homology;
KW   Acetylcholine receptor inhibiting toxin; Disulfide bond;
KW   Ion channel impairing toxin; Neurotoxin; Postsynaptic neurotoxin; Secreted;
KW   Signal; Toxin.
FT   SIGNAL          1..21
FT                   /evidence="ECO:0000255"
FT   CHAIN           22..92
FT                   /note="Long neurotoxin 1"
FT                   /id="PRO_0000316164"
FT   DISULFID        24..41
FT                   /evidence="ECO:0000250"
FT   DISULFID        34..62
FT                   /evidence="ECO:0000250"
FT   DISULFID        47..51
FT                   /evidence="ECO:0000250"
FT   DISULFID        66..77
FT                   /evidence="ECO:0000250"
FT   DISULFID        78..83
FT                   /evidence="ECO:0000250"
SQ   SEQUENCE   92 AA;  10218 MW;  8B879C95B4C1C42E CRC64;
     MKILLLTLVV VTIVCLDLAY TRTCFRTPYK PETCPPGQNL CYKKSWCDAF CSSRGKVIEL
     GCTAKCPTVK DGKDITCCAT DNCNTVANWK SR