ID   3NX4_MICFR              Reviewed;          64 AA.
AC   P86423;
DT   15-JUN-2010, integrated into UniProtKB/Swiss-Prot.
DT   15-JUN-2010, sequence version 1.
DT   25-MAY-2022, entry version 34.
DE   RecName: Full=Frontoxin IV {ECO:0000303|PubMed:20331995};
DE            Short=FTx IV {ECO:0000303|PubMed:20331995};
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, FUNCTION, SUBCELLULAR LOCATION, AND MASS SPECTROMETRY.
RC   TISSUE=Venom {ECO:0000269|PubMed:20331995};
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).
CC   -!- FUNCTION: Produces peripheral paralysis by blocking neuromuscular
CC       transmission at the postsynaptic site. Binds to the muscular nicotinic
CC       acetylcholine receptor (nAChR). {ECO:0000269|PubMed:20331995}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000269|PubMed:20331995}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland. {ECO:0000305}.
CC   -!- MASS SPECTROMETRY: Mass=7411; Method=Electrospray;
CC       Evidence={ECO:0000269|PubMed:20331995};
CC   -!- SIMILARITY: Belongs to the snake three-finger toxin family. Ancestral
CC       subfamily. {ECO:0000305}.
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DR   AlphaFoldDB; P86423; -.
DR   SMR; P86423; -.
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..64
FT                   /note="Frontoxin IV"
FT                   /evidence="ECO:0000269|PubMed:20331995"
FT                   /id="PRO_0000394462"
FT   DISULFID        3..24
FT                   /evidence="ECO:0000250|UniProtKB:Q9YGJ0"
FT   DISULFID        6..11
FT                   /evidence="ECO:0000250|UniProtKB:Q9YGJ0"
FT   DISULFID        17..41
FT                   /evidence="ECO:0000250|UniProtKB:Q9YGJ0"
FT   DISULFID        45..57
FT                   /evidence="ECO:0000250|UniProtKB:Q9YGJ0"
FT   DISULFID        58..63
FT                   /evidence="ECO:0000250|UniProtKB:Q9YGJ0"
SQ   SEQUENCE   64 AA;  7420 MW;  ED491F1D277D6CDE CRC64;
     MTCKTCPFET CANSEYCPAG NDICYQKKWN DHREEMIERG CVANCPQMES HHTSLLCCRR
     DNCN