ID   3L2B_LATCO              Reviewed;          69 AA.
AC   P0C8R8;
DT   10-FEB-2009, integrated into UniProtKB/Swiss-Prot.
DT   10-FEB-2009, sequence version 1.
DT   25-MAY-2022, entry version 37.
DE   RecName: Full=Toxin Lc b;
OS   Laticauda colubrina (Yellow-lipped sea krait) (Banded sea krait).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi;
OC   Lepidosauria; Squamata; Bifurcata; Unidentata; Episquamata; Toxicofera;
OC   Serpentes; Colubroidea; Elapidae; Laticaudinae; Laticauda.
OX   NCBI_TaxID=8628;
RN   [1]
RP   PROTEIN SEQUENCE, TOXIC DOSE, AND SUBCELLULAR LOCATION.
RC   STRAIN=Philippines; TISSUE=Venom;
RX   PubMed=7159381; DOI=10.1042/bj2070215;
RA   Kim H.S., Tamiya N.;
RT   "Amino acid sequences of two novel long-chain neurotoxins from the venom of
RT   the sea snake Laticauda colubrina.";
RL   Biochem. J. 207:215-223(1982).
CC   -!- FUNCTION: Binds with high affinity to muscular nicotinic acetylcholine
CC       receptors (nAChRs), whereas it binds with a low affinity to neuronal
CC       alpha-7/CHRNA7 nAChRs. {ECO:0000250|UniProtKB:P0C8R6}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000269|PubMed:7159381}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland. {ECO:0000305}.
CC   -!- TOXIC DOSE: LD(50) is 0.12 mg/kg by intramuscular injection into mice.
CC       {ECO:0000269|PubMed:7159381}.
CC   -!- MISCELLANEOUS: Has the length of long neurotoxins, but only 4 disulfide
CC       bonds, as short neurotoxins.
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; P0C8R8; -.
DR   SMR; P0C8R8; -.
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..69
FT                   /note="Toxin Lc b"
FT                   /id="PRO_0000364185"
FT   DISULFID        3..20
FT                   /evidence="ECO:0000250"
FT   DISULFID        13..41
FT                   /evidence="ECO:0000250"
FT   DISULFID        45..56
FT                   /evidence="ECO:0000250"
FT   DISULFID        57..62
FT                   /evidence="ECO:0000250"
SQ   SEQUENCE   69 AA;  7583 MW;  95E7F0C3145BEA5A CRC64;
     RICYLAPRDT QICAPGQEIC YLKSWDDGTG SIRGNRLEFG CAATCPTVKR GIHIKCCSTD
     KCNPHPKLA