ID   3L22_NAJNA              Reviewed;          71 AA.
AC   P25669; P01392;
DT   21-JUL-1986, integrated into UniProtKB/Swiss-Prot.
DT   21-JUL-1986, sequence version 1.
DT   03-AUG-2022, entry version 81.
DE   RecName: Full=Long neurotoxin 2;
DE   AltName: Full=Toxin B {ECO:0000303|PubMed:992083};
OS   Naja naja (Indian cobra).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi;
OC   Lepidosauria; Squamata; Bifurcata; Unidentata; Episquamata; Toxicofera;
OC   Serpentes; Colubroidea; Elapidae; Elapinae; Naja.
OX   NCBI_TaxID=35670;
RN   [1]
RP   PROTEIN SEQUENCE, AND SUBCELLULAR LOCATION.
RC   TISSUE=Venom;
RX   PubMed=992083; DOI=10.1016/0014-5793(76)80921-0;
RA   Ohta M., Sasaki T., Hayashi K.;
RT   "The primary structure of toxin B from the venom of the Indian cobra Naja
RT   naja.";
RL   FEBS Lett. 72:161-166(1976).
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:992083}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC       {ECO:0000305|PubMed:992083}.
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; A91434; N2NJ1I.
DR   AlphaFoldDB; P25669; -.
DR   SMR; P25669; -.
DR   Proteomes; UP000694559; 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="Long neurotoxin 2"
FT                   /evidence="ECO:0000269|PubMed:992083"
FT                   /id="PRO_0000093548"
FT   DISULFID        3..20
FT                   /evidence="ECO:0000250|UniProtKB:P25671"
FT   DISULFID        14..41
FT                   /evidence="ECO:0000250|UniProtKB:P25671"
FT   DISULFID        26..30
FT                   /evidence="ECO:0000250|UniProtKB:P25671"
FT   DISULFID        45..56
FT                   /evidence="ECO:0000250|UniProtKB:P25671"
FT   DISULFID        57..62
FT                   /evidence="ECO:0000250|UniProtKB:P25671"
SQ   SEQUENCE   71 AA;  7821 MW;  0256777D6277C090 CRC64;
     IRCFITPDIT SKDCPNGHVC YTKTWCDGFC SSRGKRVDLG CAATCPTVRT GVDIQCCSTD
     DCDPFPTRKR P