ID   3L22_HYDHA              Reviewed;          93 AA.
AC   A3FM53;
DT   15-JAN-2008, integrated into UniProtKB/Swiss-Prot.
DT   20-MAR-2007, sequence version 1.
DT   25-MAY-2022, entry version 51.
DE   RecName: Full=Long neurotoxin 2;
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   Tan T., Bi Q., Xiang X., Zhu S.;
RT   "The study of the neurotoxins in sea snake using cDNA phage display
RT   technology.";
RL   Submitted (JAN-2007) 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; EF405871; ABN54806.1; -; mRNA.
DR   AlphaFoldDB; A3FM53; -.
DR   SMR; A3FM53; -.
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..93
FT                   /note="Long neurotoxin 2"
FT                   /id="PRO_5000225732"
FT   DISULFID        24..42
FT                   /evidence="ECO:0000250"
FT   DISULFID        35..63
FT                   /evidence="ECO:0000250"
FT   DISULFID        48..52
FT                   /evidence="ECO:0000250"
FT   DISULFID        67..78
FT                   /evidence="ECO:0000250"
FT   DISULFID        79..84
FT                   /evidence="ECO:0000250"
SQ   SEQUENCE   93 AA;  10406 MW;  4A0E9059BF181CFB CRC64;
     MKILLLTLVV VTIVCLDLAY TRTCYRTHPY KPETCPPGQN LCYKKSWCDA FCSSRGKVIE
     LGCTAKCPTV KHGKDINCCA TDNCNTVANW KSR