ID   CA12_CONIM              Reviewed;          17 AA.
AC   Q8I6R5;
DT   16-JAN-2004, integrated into UniProtKB/Swiss-Prot.
DT   01-MAR-2003, sequence version 1.
DT   25-MAY-2022, entry version 64.
DE   RecName: Full=Alpha-conotoxin ImII {ECO:0000303|PubMed:12384509};
DE            Short=Alpha-CTx ImII {ECO:0000303|PubMed:12384509};
DE   Flags: Precursor; Fragment;
OS   Conus imperialis (Imperial cone).
OC   Eukaryota; Metazoa; Spiralia; Lophotrochozoa; Mollusca; Gastropoda;
OC   Caenogastropoda; Neogastropoda; Conoidea; Conidae; Conus; Stephanoconus.
OX   NCBI_TaxID=35631;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA], SYNTHESIS OF 5-16, FUNCTION, AND
RP   MUTAGENESIS OF ARG-10.
RC   TISSUE=Venom duct;
RX   PubMed=12384509; DOI=10.1074/jbc.m204565200;
RA   Ellison M.A., McIntosh J.M., Olivera B.M.;
RT   "Alpha-conotoxins ImI and ImII: similar alpha 7 nicotinic receptor
RT   antagonists act at different sites.";
RL   J. Biol. Chem. 278:757-764(2003).
RN   [2]
RP   FUNCTION, AMIDATION AT CYS-16, AND SYNTHESIS OF 5-16.
RX   PubMed=15609996; DOI=10.1021/bi048918g;
RA   Ellison M., Gao F., Wang H.L., Sine S.M., McIntosh J.M., Olivera B.M.;
RT   "Alpha-conotoxins ImI and ImII target distinct regions of the human alpha7
RT   nicotinic acetylcholine receptor and distinguish human nicotinic receptor
RT   subtypes.";
RL   Biochemistry 43:16019-16026(2004).
CC   -!- FUNCTION: Alpha-conotoxins act on postsynaptic membranes, they bind to
CC       the nicotinic acetylcholine receptors (nAChR) and thus inhibit them.
CC       This toxin blocks neuronal mammalian alpha-7 (human and rat) and alpha-
CC       3/beta-2 (human) and muscle alpha-1-beta-1-delta-epsilon (human) nAChRs
CC       (PubMed:12384509, PubMed:15609996). Acts voltage-independently
CC       (PubMed:12384509). Does not competes with alpha-bungarotoxin for
CC       binding to the receptor (PubMed:12384509, PubMed:15609996). Binds to a
CC       different site than alpha-conotoxin ImI (PubMed:15609996).
CC       {ECO:0000269|PubMed:12384509, ECO:0000269|PubMed:15609996}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000250|UniProtKB:P50983}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom duct. {ECO:0000305}.
CC   -!- DOMAIN: The cysteine framework is I (CC-C-C). Alpha4/3 pattern.
CC       {ECO:0000305}.
CC   -!- MISCELLANEOUS: Does not inhibit alpha-2-beta-2, alpha-2-beta-4, alpha-
CC       3-beta-4, alpha-4-beta-2, alpha-4-beta-2 nAChRs.
CC       {ECO:0000269|PubMed:15609996}.
CC   -!- SIMILARITY: Belongs to the conotoxin A superfamily. {ECO:0000305}.
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DR   EMBL; AY159317; AAN78127.1; -; Genomic_DNA.
DR   AlphaFoldDB; Q8I6R5; -.
DR   ConoServer; 92; ImII precursor.
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:0099106; F:ion channel regulator activity; IEA:UniProtKB-KW.
DR   GO; GO:0090729; F:toxin activity; IEA:UniProtKB-KW.
DR   PROSITE; PS60014; ALPHA_CONOTOXIN; 1.
PE   1: Evidence at protein level;
KW   Acetylcholine receptor inhibiting toxin; Amidation;
KW   Cleavage on pair of basic residues; Disulfide bond;
KW   Ion channel impairing toxin; Neurotoxin; Postsynaptic neurotoxin; Secreted;
KW   Toxin.
FT   PROPEP          <1..4
FT                   /evidence="ECO:0000305|PubMed:12384509"
FT                   /id="PRO_0000388685"
FT   PEPTIDE         5..16
FT                   /note="Alpha-conotoxin ImII"
FT                   /evidence="ECO:0000305|PubMed:12384509"
FT                   /id="PRO_0000034878"
FT   MOD_RES         16
FT                   /note="Cysteine amide"
FT                   /evidence="ECO:0000305|PubMed:12384509"
FT   DISULFID        6..12
FT                   /evidence="ECO:0000250|UniProtKB:P0C1D0,
FT                   ECO:0000305|PubMed:12384509"
FT   DISULFID        7..16
FT                   /evidence="ECO:0000250|UniProtKB:P0C1D0,
FT                   ECO:0000305|PubMed:12384509"
FT   MUTAGEN         10
FT                   /note="R->P: Gain of ability to compete with alpha-
FT                   bungarotoxin."
FT                   /evidence="ECO:0000269|PubMed:12384509"
FT   NON_TER         1
SQ   SEQUENCE   17 AA;  2096 MW;  CF90D9CEBB4C79CC CRC64;
     IVRRACCSDR RCRWRCG