ID   3L23_OPHHA              Reviewed;          73 AA.
AC   P07526;
DT   01-APR-1988, integrated into UniProtKB/Swiss-Prot.
DT   01-APR-1988, sequence version 1.
DT   25-MAY-2022, entry version 85.
DE   RecName: Full=Long neurotoxin 3;
DE   AltName: Full=Neurotoxin CM-9;
OS   Ophiophagus hannah (King cobra) (Naja hannah).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi;
OC   Lepidosauria; Squamata; Bifurcata; Unidentata; Episquamata; Toxicofera;
OC   Serpentes; Colubroidea; Elapidae; Elapinae; Ophiophagus.
OX   NCBI_TaxID=8665;
RN   [1]
RP   PROTEIN SEQUENCE, AND SUBCELLULAR LOCATION.
RC   TISSUE=Venom;
RA   Lin N.Q., Zhang Y.S., Mu J.F., Wang W.Y., Yang C.J., Xiong Y.L.;
RT   "Amino-acid sequence of the neurotoxin (CM-9) from the snake venom of
RT   Quangxi king cobra.";
RL   Sheng Wu Hua Xue Yu Sheng Wu Wu Li Xue Bao 16:592-596(1984).
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|Ref.1}.
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   PIR; JC0005; N2OH3.
DR   AlphaFoldDB; P07526; -.
DR   SMR; P07526; -.
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   SUPFAM; SSF57302; SSF57302; 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; Secreted; Toxin.
FT   CHAIN           1..73
FT                   /note="Long neurotoxin 3"
FT                   /id="PRO_0000093558"
FT   DISULFID        3..21
FT   DISULFID        14..42
FT   DISULFID        27..31
FT   DISULFID        46..57
FT   DISULFID        58..63
SQ   SEQUENCE   73 AA;  7957 MW;  EEBA1F86EC9544CB CRC64;
     TKCYVTPDVK SETCPAGQDL CYTETWCVAW CTVRGKRVSL TCAAICPIVP PKVSIKCCST
     DACGPFPTWP NVR