ID   3S1CB_NAJNA             Reviewed;          83 AA.
AC   Q9PTT0;
DT   13-APR-2004, integrated into UniProtKB/Swiss-Prot.
DT   01-MAY-2000, sequence version 1.
DT   03-AUG-2022, entry version 83.
DE   RecName: Full=Cobrotoxin homolog;
DE   AltName: Full=Short neurotoxin;
DE   Flags: Precursor;
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   NUCLEOTIDE SEQUENCE [MRNA].
RC   TISSUE=Venom gland;
RA   Qin C., Zhiyong H.;
RL   Submitted (MAY-1998) to the EMBL/GenBank/DDBJ databases.
RN   [2]
RP   STRUCTURE BY NMR OF 22-83, DISULFIDE BONDS, AND SUBCELLULAR LOCATION.
RC   TISSUE=Venom;
RX   PubMed=8443154; DOI=10.1021/bi00060a002;
RA   Yu C., Bhaskaran R., Chuang L.-C., Yang C.-C.;
RT   "Solution conformation of cobrotoxin: a nuclear magnetic resonance and
RT   hybrid distance geometry-dynamical simulated annealing study.";
RL   Biochemistry 32:2131-2136(1993).
CC   -!- FUNCTION: Binds to muscle nicotinic acetylcholine receptor (nAChR) and
CC       inhibit acetylcholine from binding to the receptor, thereby impairing
CC       neuromuscular transmission. {ECO:0000250|UniProtKB:P60775}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000269|PubMed:8443154}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland. {ECO:0000305}.
CC   -!- SIMILARITY: Belongs to the snake three-finger toxin family. Short-chain
CC       subfamily. Type I alpha-neurotoxin sub-subfamily. {ECO:0000305}.
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DR   EMBL; AF068052; AAF21774.1; -; mRNA.
DR   PDB; 1COD; NMR; -; A=22-83.
DR   PDBsum; 1COD; -.
DR   AlphaFoldDB; Q9PTT0; -.
DR   BMRB; Q9PTT0; -.
DR   SMR; Q9PTT0; -.
DR   EvolutionaryTrace; Q9PTT0; -.
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   3D-structure; Acetylcholine receptor inhibiting toxin; Disulfide bond;
KW   Ion channel impairing toxin; Neurotoxin; Postsynaptic neurotoxin;
KW   Reference proteome; Secreted; Signal; Toxin.
FT   SIGNAL          1..21
FT                   /evidence="ECO:0000269|PubMed:8443154"
FT   CHAIN           22..83
FT                   /note="Cobrotoxin homolog"
FT                   /evidence="ECO:0000269|PubMed:8443154"
FT                   /id="PRO_0000035455"
FT   SITE            54
FT                   /note="May be critical for toxicity"
FT                   /evidence="ECO:0000250"
FT   SITE            57
FT                   /note="May be critical for toxicity"
FT                   /evidence="ECO:0000250"
FT   DISULFID        24..45
FT                   /evidence="ECO:0000269|PubMed:8443154,
FT                   ECO:0000312|PDB:1COD"
FT   DISULFID        38..62
FT                   /evidence="ECO:0000269|PubMed:8443154,
FT                   ECO:0000312|PDB:1COD"
FT   DISULFID        64..75
FT                   /evidence="ECO:0000269|PubMed:8443154,
FT                   ECO:0000312|PDB:1COD"
FT   DISULFID        76..81
FT                   /evidence="ECO:0000269|PubMed:8443154,
FT                   ECO:0000312|PDB:1COD"
FT   STRAND          24..31
FT                   /evidence="ECO:0007829|PDB:1COD"
FT   STRAND          33..36
FT                   /evidence="ECO:0007829|PDB:1COD"
FT   STRAND          45..50
FT                   /evidence="ECO:0007829|PDB:1COD"
FT   STRAND          57..59
FT                   /evidence="ECO:0007829|PDB:1COD"
FT   STRAND          69..76
FT                   /evidence="ECO:0007829|PDB:1COD"
FT   STRAND          78..80
FT                   /evidence="ECO:0007829|PDB:1COD"
SQ   SEQUENCE   83 AA;  9262 MW;  4DDC0DDC387BD0F2 CRC64;
     METLLLTLLV VTIVCLDLGY TLECHNQQSS QTPTTTGCSG GETNCYKKRW RDHRGYRTER
     GCGCPSVKNG IEINCCTTDR CNN