ID   3S1CB_NAJKA             Reviewed;          83 AA.
AC   P60771; O13079; P01430; Q4PLR9;
DT   21-JUL-1986, integrated into UniProtKB/Swiss-Prot.
DT   03-OCT-2006, sequence version 2.
DT   25-MAY-2022, entry version 71.
DE   RecName: Full=Cobrotoxin;
DE            Short=CBT;
DE   AltName: Full=Short neurotoxin I {ECO:0000303|PubMed:11904231};
DE            Short=NT1 {ECO:0000303|PubMed:11904231};
DE   Flags: Precursor;
OS   Naja kaouthia (Monocled cobra) (Naja siamensis).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi;
OC   Lepidosauria; Squamata; Bifurcata; Unidentata; Episquamata; Toxicofera;
OC   Serpentes; Colubroidea; Elapidae; Elapinae; Naja.
OX   NCBI_TaxID=8649;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA].
RC   TISSUE=Venom gland;
RA   Yao G.-T., Wei X.-H., Yu L.-X., Wang Z.-S., Feng Y., Song H., Zhang B.-B.;
RT   "Cloning and expression of neurotoxin cDNA from Naja naja kaouthia
RT   lesson.";
RL   Submitted (MAY-2005) to the EMBL/GenBank/DDBJ databases.
RN   [2]
RP   PROTEIN SEQUENCE OF 22-83, TOXIC DOSE, AND SUBCELLULAR LOCATION.
RC   TISSUE=Venom;
RX   PubMed=12039691; DOI=10.1016/s1532-0456(02)00049-2;
RA   Meng Q.-X., Wang W.-Y., Lu Q.-M., Jin Y., Wei J.-F., Zhu S.-W.,
RA   Xiong Y.-L.;
RT   "A novel short neurotoxin, cobrotoxin c, from monocellate cobra (Naja
RT   kaouthia) venom: isolation and purification, primary and secondary
RT   structure determination, and tertiary structure modeling.";
RL   Comp. Biochem. Physiol. 132C:113-121(2002).
RN   [3]
RP   INHIBITORY CONCENTRATION.
RX   PubMed=11904231; DOI=10.1016/s0167-4838(01)00326-0;
RA   Cheng Y., Meng Q.-X., Wang W.-Y., Wang J.;
RT   "Structure-function relationship of three neurotoxins from the venom of
RT   Naja kaouthia: a comparison between the NMR-derived structure of NT2 with
RT   its homologues, NT1 and NT3.";
RL   Biochim. Biophys. Acta 1594:353-363(2002).
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:12039691}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland. {ECO:0000305}.
CC   -!- TOXIC DOSE: LD(50) is 65 mg/kg by intraperitoneal injection into mice.
CC       {ECO:0000269|PubMed:12039691}.
CC   -!- MISCELLANEOUS: It inhibits muscle contraction with an IC(50) of 0.04
CC       ug/ml. {ECO:0000305|PubMed:11904231}.
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; DQ066882; AAY63884.1; -; mRNA.
DR   AlphaFoldDB; P60771; -.
DR   BMRB; P60771; -.
DR   SMR; P60771; -.
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; Secreted; Signal; Toxin.
FT   SIGNAL          1..21
FT                   /evidence="ECO:0000269|PubMed:12039691"
FT   CHAIN           22..83
FT                   /note="Cobrotoxin"
FT                   /evidence="ECO:0000269|PubMed:12039691"
FT                   /id="PRO_0000093591"
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:0000250|UniProtKB:P0C1Z0"
FT   DISULFID        38..62
FT                   /evidence="ECO:0000250|UniProtKB:P0C1Z0"
FT   DISULFID        64..75
FT                   /evidence="ECO:0000250|UniProtKB:P0C1Z0"
FT   DISULFID        76..81
FT                   /evidence="ECO:0000250|UniProtKB:P0C1Z0"
SQ   SEQUENCE   83 AA;  9262 MW;  4DD6077C92717052 CRC64;
     MKTLLLTLLV VTIVCLDLGY TLECHNQQSS QTPTTTGCSG GETNCYKKRW RDHRGYRTER
     GCGCPSVKNG IEINCCTTDR CNN