ID   3NOH_BUNMU              Reviewed;         103 AA.
AC   Q9PW19;
DT   01-FEB-2003, integrated into UniProtKB/Swiss-Prot.
DT   01-MAY-2000, sequence version 1.
DT   25-MAY-2022, entry version 71.
DE   RecName: Full=Toxin BMLCL {ECO:0000303|PubMed:10380637};
DE   AltName: Full=BM8 {ECO:0000303|PubMed:12437132};
DE   Flags: Precursor;
OS   Bungarus multicinctus (Many-banded krait).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi;
OC   Lepidosauria; Squamata; Bifurcata; Unidentata; Episquamata; Toxicofera;
OC   Serpentes; Colubroidea; Elapidae; Bungarinae; Bungarus.
OX   NCBI_TaxID=8616;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA].
RC   TISSUE=Venom gland;
RX   PubMed=10380637; DOI=10.1271/bbb.63.940;
RA   Qian Y.-C., Fan C.-Y., Gong Y., Yang S.-L.;
RT   "cDNA sequence analysis of a novel member of the three loop protein family
RT   from the Chinese continental banded krait.";
RL   Biosci. Biotechnol. Biochem. 63:940-942(1999).
RN   [2]
RP   PROTEIN SEQUENCE OF 22-103, MASS SPECTROMETRY, AND SUBCELLULAR LOCATION.
RC   TISSUE=Venom;
RX   PubMed=12437132; DOI=10.1515/bc.2002.158;
RA   Chung C., Wu B.N., Yang C.C., Chang L.S.;
RT   "Muscarinic toxin-like proteins from Taiwan banded krait (Bungarus
RT   multicinctus) venom: purification, characterization and gene
RT   organization.";
RL   Biol. Chem. 383:1397-1406(2002).
RN   [3]
RP   FUNCTION, AND IDENTIFICATION BY MASS SPECTROMETRY.
RC   TISSUE=Venom;
RX   PubMed=26518551; DOI=10.1134/s1607672915050099;
RA   Utkin Y.N., Kasheverov I.E., Kudryavtsev D.S., Andreeva T.V., Starkov V.G.,
RA   Ziganshin R.H., Kuznetsov D.V., Anh H.N., Thao N.T., Khoa N.C.,
RA   Tsetlin V.I.;
RT   "Nonconventional three-finger toxin BMLCL from krait Bungarus multicinctus
RT   venom with high affinity interacts with nicotinic acetylcholine
RT   receptors.";
RL   Dokl. Biochem. Biophys. 464:294-297(2015).
CC   -!- FUNCTION: Interacts with high efficiency with both neuronal alpha-
CC       7/CHRNA7 and muscle type nicotinic acetylcholine receptors (nAChRs).
CC       Tested on human alpha-7/CHRNA7 nAChR (IC(50)=42 nM), T.californica
CC       muscle receptor (IC(50)=31 nM), L.stagnalis and A.californica
CC       acetylcholine-binding proteins (IC(50)=333 nM and 3.4 uM,
CC       respectively). {ECO:0000269|PubMed:26518551}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000269|PubMed:12437132}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC       {ECO:0000305|PubMed:12437132}.
CC   -!- MASS SPECTROMETRY: Mass=9019; Method=Electrospray;
CC       Evidence={ECO:0000269|PubMed:12437132};
CC   -!- MISCELLANEOUS: Does not bind to muscarinic acetylcholine receptors M1
CC       and M2 (CHRM1/CHRM2). Is unable to compete with alpha-bungarotoxin for
CC       binding to nAchR at concentrations up to 100 uM. Is not toxic to mice
CC       at doses up to 3 mg/kg. {ECO:0000269|PubMed:12437132}.
CC   -!- SIMILARITY: Belongs to the snake three-finger toxin family. Ancestral
CC       subfamily. Orphan group XVII sub-subfamily. {ECO:0000305}.
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DR   EMBL; AJ007741; CAB53358.1; -; mRNA.
DR   AlphaFoldDB; Q9PW19; -.
DR   SMR; Q9PW19; -.
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: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; Neurotoxin; Postsynaptic neurotoxin; Secreted; Signal;
KW   Toxin.
FT   SIGNAL          1..21
FT                   /evidence="ECO:0000269|PubMed:12437132"
FT   CHAIN           22..103
FT                   /note="Toxin BMLCL"
FT                   /evidence="ECO:0000269|PubMed:12437132"
FT                   /id="PRO_0000035423"
FT   DISULFID        24..45
FT                   /evidence="ECO:0000250|UniProtKB:P81782"
FT   DISULFID        27..37
FT                   /evidence="ECO:0000250|UniProtKB:P81782"
FT   DISULFID        38..72
FT                   /evidence="ECO:0000250|UniProtKB:P81782"
FT   DISULFID        76..90
FT                   /evidence="ECO:0000250|UniProtKB:P81782"
FT   DISULFID        91..96
FT                   /evidence="ECO:0000250|UniProtKB:P81782"
SQ   SEQUENCE   103 AA;  11334 MW;  765923F90C63C659 CRC64;
     MKTLLLTLVV VTIICLDLGY TEMCNMCVRP YPFMSSCCPE GQDRCYKSYW VNENGKQEAY
     HGKYPVILER GCVTACTGPG SGSIYNLYTC CPTNRCGSSS TSG