ID   CA1B_CONVE              Reviewed;          42 AA.
AC   A0A4P8XV20;
DT   29-SEP-2021, integrated into UniProtKB/Swiss-Prot.
DT   29-SEP-2021, sequence version 2.
DT   23-FEB-2022, entry version 10.
DE   RecName: Full=Alpha-conotoxin VnIB {ECO:0000303|PubMed:31255696};
DE   Flags: Precursor; Fragment;
OS   Conus ventricosus (Mediterranean cone).
OC   Eukaryota; Metazoa; Spiralia; Lophotrochozoa; Mollusca; Gastropoda;
OC   Caenogastropoda; Neogastropoda; Conoidea; Conidae; Conus; Lautoconus.
OX   NCBI_TaxID=117992;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA], SYNTHESIS OF 23-39, AMIDATION AT GLY-39,
RP   AND DISULFIDE BOND.
RX   PubMed=31255696; DOI=10.1016/j.neuropharm.2019.107691;
RA   van Hout M., Valdes A., Christensen S.B., Tran P.T., Watkins M.,
RA   Gajewiak J., Jensen A.A., Olivera B.M., McIntosh J.M.;
RT   "Alpha-conotoxin VnIB from Conus ventricosus is a potent and selective
RT   antagonist of alpha6beta4* nicotinic acetylcholine receptors.";
RL   Neuropharmacology 157:107691-107691(2019).
CC   -!- FUNCTION: Alpha-conotoxins act on postsynaptic membranes, they bind to
CC       the nicotinic acetylcholine receptors (nAChR) and thus inhibit them
CC       (PubMed:31255696). This toxin potently and selectively inhibits human
CC       and rat alpha-6-beta-4/CHRNA6-CHRNB4 nAChR (IC(50)=12 nM on rat nAChR)
CC       (PubMed:31255696). It exhibits rapid binding and unbinding at this
CC       receptor (PubMed:31255696). It also shows activity on rat alpha-6-beta-
CC       4/CHRNA6-CHRNB4 (IC(50)=12 nM), human alpha-6/alpha-3-beta-4
CC       (CHRNA6/CHRNA3-CHRNB4) (IC(50)=5.3 nM), rat alpha-6/alpha-3-beta-4
CC       (CHRNA6/CHRNA3-CHRNB4) (IC(50)=18 nM), rat alpha-3-beta-4/CHRNA3-CHRNB4
CC       (IC(50)=320 nM), and rat alpha-6/alpha-3-beta-2-beta-3 (CHRNA6/CHRNA3-
CC       CHRNB2-CHRNB3) (IC(50)=4 uM) (PubMed:31255696).
CC       {ECO:0000269|PubMed:31255696}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000305|PubMed:31255696}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom duct.
CC       {ECO:0000305|PubMed:31255696}.
CC   -!- DOMAIN: The cysteine framework is I (CC-C-C). Alpha4/6 pattern.
CC       {ECO:0000305}.
CC   -!- MISCELLANEOUS: Has no effect on human alpha-1-beta-1-delta-
CC       epsilon/CHRNA1-CHRNB1-CHRNE-CHRND, rat alpha-2-beta-2/CHRNA2-CHRNB2,
CC       rat alpha-2 beta-4/CHRNA2-CHRNB4, rat alpha-3 beta-2/CHRNA3-CHRNB2, rat
CC       alpha-4 beta-2/CHRNA4-CHRNB2, rat alpha-4 beta-4/CHRNA4-CHRNB4, rat
CC       alpha-7/CHRNA7, rat alpha-9-alpha-10/CHRNA9-CHRNA10, human alpha-3-
CC       beta-4/CHRNA3-CHRNB4, human alpha-6/alpha-3-beta-2-beta-3
CC       (CHRNA6/CHRNA3 AND CHRNB2 AND CHRNB3), human alpha-4-beta-2/CHRNA4-
CC       CHRNB2. {ECO:0000269|PubMed:31255696}.
CC   -!- SIMILARITY: Belongs to the conotoxin A superfamily. {ECO:0000305}.
CC   -!- SEQUENCE CAUTION:
CC       Sequence=QCT05780.1; Type=Erroneous initiation; Note=Extended N-terminus.; Evidence={ECO:0000305};
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DR   EMBL; MK120500; QCT05780.1; ALT_INIT; Genomic_DNA.
DR   GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR   GO; GO:0035792; C:host cell postsynaptic membrane; IEA:UniProtKB-KW.
DR   GO; GO:0030550; F:acetylcholine receptor inhibitor activity; IEA:UniProtKB-KW.
DR   GO; GO:0090729; F:toxin activity; IEA:UniProtKB-KW.
DR   InterPro; IPR009958; Conotoxin_a-typ.
DR   Pfam; PF07365; Toxin_8; 1.
PE   1: Evidence at protein level;
KW   Acetylcholine receptor inhibiting toxin; Amidation; Disulfide bond;
KW   Neurotoxin; Postsynaptic neurotoxin; Secreted; Toxin.
FT   PROPEP          <1..22
FT                   /evidence="ECO:0000305|PubMed:31255696"
FT                   /id="PRO_0000453394"
FT   PEPTIDE         23..39
FT                   /note="Alpha-conotoxin VnIB"
FT                   /evidence="ECO:0000305|PubMed:31255696"
FT                   /id="PRO_0000453395"
FT   MOD_RES         39
FT                   /note="Glycine amide"
FT                   /evidence="ECO:0000250|UniProtKB:P85886,
FT                   ECO:0000305|PubMed:31255696"
FT   DISULFID        25..31
FT                   /evidence="ECO:0000305|PubMed:31255696"
FT   DISULFID        26..38
FT                   /evidence="ECO:0000305|PubMed:31255696"
FT   NON_TER         1
FT                   /evidence="ECO:0000305|PubMed:31255696"
SQ   SEQUENCE   42 AA;  4306 MW;  3F7D4FAB49F8C15F CRC64;
     ASDGRNAAAD DKASDPIALT VRGGCCSHPV CYTKNPNCGG RR