ID   3L25_OPHHA              Reviewed;          72 AA.
AC   P80965;
DT   01-NOV-1997, integrated into UniProtKB/Swiss-Prot.
DT   01-NOV-1997, sequence version 1.
DT   25-MAY-2022, entry version 83.
DE   RecName: Full=Long neurotoxin OH-5;
DE   AltName: Full=Alpha-neurotoxin;
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=9163519; DOI=10.1093/oxfordjournals.jbchem.a021641;
RA   Lin S.-R., Leu L.-F., Chang L.-S., Chang C.-C.;
RT   "Amino acid sequence and chemical modification of a novel alpha-neurotoxin
RT   (Oh-5) from king cobra (Ophiophagus hannah) venom.";
RL   J. Biochem. 121:690-695(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:9163519}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland. {ECO:0000305}.
CC   -!- TOXIC DOSE: LD(50) is 0.25 mg/kg by intraperitoneal injection into
CC       mice. {ECO:0000269|PubMed:9163519}.
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   AlphaFoldDB; P80965; -.
DR   SMR; P80965; -.
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   Acetylcholine receptor inhibiting toxin; Direct protein sequencing;
KW   Disulfide bond; Ion channel impairing toxin; Neurotoxin;
KW   Postsynaptic neurotoxin; Secreted; Toxin.
FT   CHAIN           1..72
FT                   /note="Long neurotoxin OH-5"
FT                   /id="PRO_0000093560"
FT   DISULFID        3..22
FT                   /evidence="ECO:0000250"
FT   DISULFID        15..43
FT                   /evidence="ECO:0000250"
FT   DISULFID        28..32
FT                   /evidence="ECO:0000250"
FT   DISULFID        47..58
FT                   /evidence="ECO:0000250"
FT   DISULFID        59..64
FT                   /evidence="ECO:0000250"
SQ   SEQUENCE   72 AA;  8040 MW;  3278111DBA52119B CRC64;
     TKCYKTGDRI ISEACPPGQD LCYMKTWCDV FCGTRGRVIE LGCTATCPTV KPHEQITCCS
     TDNCDPHHKM LQ