ID   CA4A_CONOB              Reviewed;          18 AA.
AC   P69746;
DT   26-APR-2005, integrated into UniProtKB/Swiss-Prot.
DT   26-APR-2005, sequence version 1.
DT   25-MAY-2022, entry version 45.
DE   RecName: Full=Alpha-conotoxin OIVA;
DE            Short=Alpha-A-O4a;
DE            Short=Alpha-A-OIVA;
OS   Conus obscurus (Obscure cone) (Conus halitropus).
OC   Eukaryota; Metazoa; Spiralia; Lophotrochozoa; Mollusca; Gastropoda;
OC   Caenogastropoda; Neogastropoda; Conoidea; Conidae; Conus; Gastridium.
OX   NCBI_TaxID=89447;
RN   [1]
RP   PROTEIN SEQUENCE, SYNTHESIS, AMIDATION AT CYS-18, HYDROXYLATION AT PRO-5
RP   AND PRO-11, DISULFIDE BONDS, CHARACTERIZATION, AND MASS SPECTROMETRY.
RC   TISSUE=Venom;
RX   PubMed=15246771; DOI=10.1016/j.toxicon.2004.05.026;
RA   Teichert R.W., Rivier J., Dykert J., Cervini L., Gulyas J., Bulaj G.,
RA   Ellison M., Olivera B.M.;
RT   "AlphaA-Conotoxin OIVA defines a new alphaA-conotoxin subfamily of
RT   nicotinic acetylcholine receptor inhibitors.";
RL   Toxicon 44:207-214(2004).
RN   [2]
RP   SYNTHESIS, FUNCTION, AND MUTAGENESIS OF HIS-10.
RX   PubMed=16430227; DOI=10.1021/bi052016d;
RA   Teichert R.W., Lopez-Vera E., Gulyas J., Watkins M., Rivier J.,
RA   Olivera B.M.;
RT   "Definition and characterization of the short alphaA-conotoxins: a single
RT   residue determines dissociation kinetics from the fetal muscle nicotinic
RT   acetylcholine receptor.";
RL   Biochemistry 45:1304-1312(2006).
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 the fetal muscle subtype (alpha-1/beta-1/gamma/delta
CC       subunits) (IC(50)=0.51 nM) with 600-fold greater affinity than the
CC       adult subtype (IC(50)=310 nM). It blocks the elicited currents
CC       completely and it dissociates very slowly from the fetal muscle
CC       receptor. This toxin causes an apparently irreversible paralysis upon
CC       intramuscular injection into gold fish. {ECO:0000269|PubMed:16430227}.
CC   -!- SUBCELLULAR LOCATION: Secreted.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom duct.
CC   -!- DOMAIN: The cysteine framework is IV (CC-C-C-C-C).
CC   -!- MASS SPECTROMETRY: Mass=1848.58; Method=MALDI;
CC       Evidence={ECO:0000269|PubMed:15246771};
CC   -!- MISCELLANEOUS: The cysteine framework differs from the previously
CC       characterized alpha-A conotoxins. It also differs in its disulfide
CC       bonding. It is why authors (PubMed:15246771) propose the novel
CC       nomenclature Alpha-A(1-3) conotoxin OIVA.
CC       {ECO:0000305|PubMed:15246771}.
CC   -!- SIMILARITY: Belongs to the conotoxin A superfamily. {ECO:0000305}.
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DR   AlphaFoldDB; P69746; -.
DR   ConoServer; 1397; OIVA.
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.
PE   1: Evidence at protein level;
KW   Acetylcholine receptor inhibiting toxin; Amidation;
KW   Direct protein sequencing; Disulfide bond; Hydroxylation;
KW   Ion channel impairing toxin; Neurotoxin; Postsynaptic neurotoxin; Secreted;
KW   Toxin.
FT   PEPTIDE         1..18
FT                   /note="Alpha-conotoxin OIVA"
FT                   /id="PRO_0000044467"
FT   MOD_RES         5
FT                   /note="4-hydroxyproline"
FT                   /evidence="ECO:0000269|PubMed:15246771"
FT   MOD_RES         11
FT                   /note="4-hydroxyproline"
FT                   /evidence="ECO:0000269|PubMed:15246771"
FT   MOD_RES         18
FT                   /note="Cysteine amide"
FT                   /evidence="ECO:0000269|PubMed:15246771"
FT   DISULFID        1..9
FT                   /evidence="ECO:0000269|PubMed:15246771"
FT   DISULFID        2..14
FT                   /evidence="ECO:0000269|PubMed:15246771"
FT   DISULFID        12..18
FT                   /evidence="ECO:0000269|PubMed:15246771"
FT   MUTAGEN         10
FT                   /note="H->P: Dissociates very rapidly from the fetal muscle
FT                   receptor."
FT                   /evidence="ECO:0000269|PubMed:16430227"
SQ   SEQUENCE   18 AA;  1823 MW;  8D0E5A8667119C7E CRC64;
     CCGVPNAACH PCVCKNTC