ID   3S11_MICFR              Reviewed;          56 AA.
AC   P86420;
DT   15-JUN-2010, integrated into UniProtKB/Swiss-Prot.
DT   15-JUN-2010, sequence version 1.
DT   25-MAY-2022, entry version 37.
DE   RecName: Full=Frontoxin I {ECO:0000303|PubMed:20331995};
DE            Short=FTx I {ECO:0000303|PubMed:20331995};
DE   Flags: Fragment;
OS   Micrurus frontalis (Coral snake).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi;
OC   Lepidosauria; Squamata; Bifurcata; Unidentata; Episquamata; Toxicofera;
OC   Serpentes; Colubroidea; Elapidae; Elapinae; Micrurus.
OX   NCBI_TaxID=129461;
RN   [1]
RP   PROTEIN SEQUENCE, AND MASS SPECTROMETRY.
RC   TISSUE=Venom;
RX   PubMed=20331995; DOI=10.1016/j.toxicon.2010.02.030;
RA   Moreira K.G., Prates M.V., Andrade F.A., Silva L.P., Beirao P.S.,
RA   Kushmerick C., Naves L.A., Bloch C. Jr.;
RT   "Frontoxins, three-finger toxins from Micrurus frontalis venom, decrease
RT   miniature endplate potential amplitude at frog neuromuscular junction.";
RL   Toxicon 56:55-63(2010).
RN   [2]
RP   PROTEIN SEQUENCE OF 1-35, TOXIC DOSE, AND SUBCELLULAR LOCATION.
RX   PubMed=9278969; DOI=10.1016/s0041-0101(97)00031-7;
RA   Francis B.R., da Silva Junior N.J., Seebart C., Casais e Silva L.L.,
RA   Schmidt J.J., Kaiser I.I.;
RT   "Toxins isolated from the venom of the Brazilian coral snake (Micrurus
RT   frontalis frontalis) include hemorrhagic type phospholipases A2 and
RT   postsynaptic neurotoxins.";
RL   Toxicon 35:1193-1203(1997).
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:9278969}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland. {ECO:0000305}.
CC   -!- MASS SPECTROMETRY: Mass=6642.81; Method=Electrospray;
CC       Evidence={ECO:0000269|PubMed:20331995};
CC   -!- TOXIC DOSE: LD(50) is 0.25-0.5 mg/kg by intravenous injection into
CC       mice. {ECO:0000269|PubMed:9278969}.
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   AlphaFoldDB; P86420; -.
DR   SMR; P86420; -.
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   SUPFAM; SSF57302; SSF57302; 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..>56
FT                   /note="Frontoxin I"
FT                   /evidence="ECO:0000269|PubMed:20331995"
FT                   /id="PRO_0000394459"
FT   DISULFID        3..22
FT                   /evidence="ECO:0000250|UniProtKB:P01427"
FT   DISULFID        17..39
FT                   /evidence="ECO:0000250|UniProtKB:P01427"
FT   DISULFID        41..52
FT                   /evidence="ECO:0000250|UniProtKB:P01427"
FT   DISULFID        53..56
FT                   /evidence="ECO:0000250|UniProtKB:P01427"
FT   NON_TER         56
FT                   /evidence="ECO:0000303|PubMed:20331995"
SQ   SEQUENCE   56 AA;  6236 MW;  CEFED65BB80961DC CRC64;
     MICYNHQSSE PPTTKTCSEG QCYKKSWSDH RGTIIERGCA CPNVKPGVKI ICCRSC