ID   3L24_NAJNA              Reviewed;          71 AA.
AC   P25672;
DT   01-MAY-1992, integrated into UniProtKB/Swiss-Prot.
DT   01-MAY-1992, sequence version 1.
DT   03-AUG-2022, entry version 86.
DE   RecName: Full=Long neurotoxin 4;
DE   AltName: Full=Toxin D {ECO:0000303|PubMed:7326259};
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, TOXIC DOSE, AND SUBCELLULAR LOCATION.
RC   TISSUE=Venom;
RX   PubMed=7326259; DOI=10.1016/0005-2795(81)90125-2;
RA   Ohta M., Sasaki T., Hayashi K.;
RT   "The amino acid sequence of toxin D isolated from the venom of Indian cobra
RT   (Naja naja).";
RL   Biochim. Biophys. Acta 671:123-128(1981).
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:7326259}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC       {ECO:0000305|PubMed:7326259}.
CC   -!- TOXIC DOSE: LD(50) is 0.22 mg/kg by subcutaneous injection.
CC       {ECO:0000269|PubMed:7326259}.
CC   -!- SIMILARITY: Belongs to the snake three-finger toxin family. Long-chain
CC       subfamily. Type II alpha-neurotoxin sub-subfamily. {ECO:0000305}.
CC   ---------------------------------------------------------------------------
CC   Copyrighted by the UniProt Consortium, see https://www.uniprot.org/terms
CC   Distributed under the Creative Commons Attribution (CC BY 4.0) License
CC   ---------------------------------------------------------------------------
DR   AlphaFoldDB; P25672; -.
DR   SMR; P25672; -.
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 4"
FT                   /evidence="ECO:0000269|PubMed:7326259"
FT                   /id="PRO_0000093550"
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;  7889 MW;  66F4E0686AD55813 CRC64;
     IRCFITPDIT SKDCPNGHVC YTKTWCDGFC RIRGERVDLG CAATCPTVKT GVDIQCCSTD
     DCDPFPTRKR P