ID   3L22_OPHHA              Reviewed;          73 AA.
AC   P01386;
DT   21-JUL-1986, integrated into UniProtKB/Swiss-Prot.
DT   21-JUL-1986, sequence version 1.
DT   25-MAY-2022, entry version 108.
DE   RecName: Full=Long neurotoxin 2;
DE   AltName: Full=Neurotoxin B;
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, TOXIC DOSE, AND SUBCELLULAR LOCATION.
RC   TISSUE=Venom;
RX   PubMed=4198767;
RA   Joubert F.J.;
RT   "Snake venom toxins the amino acid sequences of two toxins from Ophiophagus
RT   hannah (King cobra) venom.";
RL   Biochim. Biophys. Acta 317:85-98(1973).
RN   [2]
RP   IDENTIFICATION BY MASS SPECTROMETRY.
RC   TISSUE=Venom;
RX   PubMed=24297900; DOI=10.1073/pnas.1314702110;
RA   Vonk F.J., Casewell N.R., Henkel C.V., Heimberg A.M., Jansen H.J.,
RA   McCleary R.J., Kerkkamp H.M., Vos R.A., Guerreiro I., Calvete J.J.,
RA   Wuster W., Woods A.E., Logan J.M., Harrison R.A., Castoe T.A.,
RA   de Koning A.P., Pollock D.D., Yandell M., Calderon D., Renjifo C.,
RA   Currier R.B., Salgado D., Pla D., Sanz L., Hyder A.S., Ribeiro J.M.,
RA   Arntzen J.W., van den Thillart G.E., Boetzer M., Pirovano W., Dirks R.P.,
RA   Spaink H.P., Duboule D., McGlinn E., Kini R.M., Richardson M.K.;
RT   "The king cobra genome reveals dynamic gene evolution and adaptation in the
RT   snake venom system.";
RL   Proc. Natl. Acad. Sci. U.S.A. 110:20651-20656(2013).
RN   [3]
RP   STRUCTURE BY NMR, AND DISULFIDE BONDS.
RX   PubMed=9065446; DOI=10.1074/jbc.272.12.7817;
RA   Peng S.S., Kumar T.K.S., Jayaraman G., Chang C.-C., Yu C.;
RT   "Solution structure of toxin b, a long neurotoxin from the venom of the
RT   king cobra (Ophiophagus hannah).";
RL   J. Biol. Chem. 272:7817-7823(1997).
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:4198767}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland. {ECO:0000305}.
CC   -!- TOXIC DOSE: LD(50) is 0.35 mg/kg by subcutaneous injection.
CC       {ECO:0000269|PubMed:4198767}.
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; A01657; N2OH2.
DR   PDB; 1TXA; NMR; -; A=1-73.
DR   PDB; 1TXB; NMR; -; A=1-73.
DR   PDBsum; 1TXA; -.
DR   PDBsum; 1TXB; -.
DR   AlphaFoldDB; P01386; -.
DR   SMR; P01386; -.
DR   TopDownProteomics; P01386; -.
DR   EvolutionaryTrace; P01386; -.
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   InterPro; IPR035076; Toxin/TOLIP.
DR   Pfam; PF00087; Toxin_TOLIP; 1.
DR   SUPFAM; SSF57302; SSF57302; 1.
DR   PROSITE; PS00272; SNAKE_TOXIN; 1.
PE   1: Evidence at protein level;
KW   3D-structure; Acetylcholine receptor inhibiting toxin;
KW   Direct protein sequencing; Disulfide bond; Ion channel impairing toxin;
KW   Neurotoxin; Postsynaptic neurotoxin; Secreted; Toxin.
FT   CHAIN           1..73
FT                   /note="Long neurotoxin 2"
FT                   /id="PRO_0000093557"
FT   DISULFID        3..21
FT                   /evidence="ECO:0000269|PubMed:9065446"
FT   DISULFID        14..42
FT                   /evidence="ECO:0000269|PubMed:9065446"
FT   DISULFID        27..31
FT                   /evidence="ECO:0000269|PubMed:9065446"
FT   DISULFID        46..57
FT                   /evidence="ECO:0000269|PubMed:9065446"
FT   DISULFID        58..63
FT                   /evidence="ECO:0000269|PubMed:9065446"
FT   STRAND          20..24
FT                   /evidence="ECO:0007829|PDB:1TXA"
FT   STRAND          29..32
FT                   /evidence="ECO:0007829|PDB:1TXA"
FT   STRAND          39..42
FT                   /evidence="ECO:0007829|PDB:1TXA"
FT   STRAND          48..50
FT                   /evidence="ECO:0007829|PDB:1TXB"
FT   STRAND          51..53
FT                   /evidence="ECO:0007829|PDB:1TXA"
FT   STRAND          55..62
FT                   /evidence="ECO:0007829|PDB:1TXA"
FT   STRAND          69..71
FT                   /evidence="ECO:0007829|PDB:1TXB"
SQ   SEQUENCE   73 AA;  8053 MW;  1C1FA8D40B750B96 CRC64;
     TKCYVTPDAT SQTCPDGQDI CYTKTWCDGF CSSRGKRIDL GCAATCPKVK PGVDIKCCST
     DNCNPFPTWK RKH