ID   3L255_OPHHA             Reviewed;          93 AA.
AC   Q53B58;
DT   15-JAN-2008, integrated into UniProtKB/Swiss-Prot.
DT   24-MAY-2005, sequence version 1.
DT   25-MAY-2022, entry version 55.
DE   RecName: Full=Long neurotoxin OH-55;
DE   AltName: Full=CM-11;
DE   Flags: Precursor;
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   NUCLEOTIDE SEQUENCE [MRNA], PROTEIN SEQUENCE OF 22-41, AND TOXIC DOSE.
RC   TISSUE=Venom, and Venom gland;
RX   PubMed=15302536; DOI=10.1016/j.toxicon.2004.06.003;
RA   He Y.-Y., Lee W.-H., Zhang Y.;
RT   "Cloning and purification of alpha-neurotoxins from king cobra (Ophiophagus
RT   hannah).";
RL   Toxicon 44:295-303(2004).
RN   [2]
RP   PROTEIN SEQUENCE OF 22-93, AND SUBCELLULAR LOCATION.
RC   TISSUE=Venom;
RA   Song J., Chung M.C.M., Xiong Y., Wang W., Pu X.;
RT   "Purification, sequence and pharmacological studies of a new alpha-
RT   neurotoxin from Ophiophagus hannah venom.";
RL   Toxicon 32:537-538(1994).
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|Ref.2}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland. {ECO:0000305}.
CC   -!- TOXIC DOSE: LD(50) is 120 ug/kg by intraperitoneal injection into mice.
CC       {ECO:0000269|PubMed:15302536}.
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   EMBL; AY596928; AAT97250.1; -; mRNA.
DR   AlphaFoldDB; Q53B58; -.
DR   SMR; Q53B58; -.
DR   TopDownProteomics; Q53B58; -.
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:15302536, ECO:0000269|Ref.2"
FT   CHAIN           22..93
FT                   /note="Long neurotoxin OH-55"
FT                   /id="PRO_5000093321"
FT   DISULFID        24..42
FT                   /evidence="ECO:0000250"
FT   DISULFID        35..63
FT                   /evidence="ECO:0000250"
FT   DISULFID        48..52
FT                   /evidence="ECO:0000250"
FT   DISULFID        67..78
FT                   /evidence="ECO:0000250"
FT   DISULFID        79..84
FT                   /evidence="ECO:0000250"
SQ   SEQUENCE   93 AA;  10210 MW;  33E203AEC5D05E42 CRC64;
     MKTLLLTLVV VTIVCLDLGY TTKCYVTPDV KSETCPAGQD ICYTETWCDA WCTSRGKRVN
     LGCAATCPIV KPGVEIKCCS TDNCNPFPTR KRP