ID   TX21C_PHONI             Reviewed;          87 AA.
AC   P0C2S6;
DT   17-APR-2007, integrated into UniProtKB/Swiss-Prot.
DT   17-APR-2007, sequence version 1.
DT   25-MAY-2022, entry version 36.
DE   RecName: Full=U9-ctenitoxin-Pn1a {ECO:0000305};
DE            Short=U9-CNTX-Pn1a {ECO:0000305};
DE   AltName: Full=Neurotoxin Pn3-3A;
DE   Flags: Precursor;
OS   Phoneutria nigriventer (Brazilian armed spider) (Ctenus nigriventer).
OC   Eukaryota; Metazoa; Ecdysozoa; Arthropoda; Chelicerata; Arachnida; Araneae;
OC   Araneomorphae; Entelegynae; Lycosoidea; Ctenidae; Phoneutria.
OX   NCBI_TaxID=6918;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA].
RC   TISSUE=Venom gland;
RX   PubMed=12782075; DOI=10.1016/s0041-0101(03)00011-4;
RA   Cardoso F.C., Pacifico L.G., Carvalho D.C., Victoria J.M.N., Neves A.L.G.,
RA   Chavez-Olortegui C., Gomez M.V., Kalapothakis E.;
RT   "Molecular cloning and characterization of Phoneutria nigriventer toxins
RT   active on calcium channels.";
RL   Toxicon 41:755-763(2003).
CC   -!- FUNCTION: Antagonist of L-type calcium channels (Cav1/CACNA1).
CC       {ECO:0000250}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000305|PubMed:12782075}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC       {ECO:0000305|PubMed:12782075}.
CC   -!- DOMAIN: The presence of a 'disulfide through disulfide knot'
CC       structurally defines this protein as a knottin.
CC       {ECO:0000250|UniProtKB:P30288}.
CC   -!- SIMILARITY: Belongs to the neurotoxin 02 (plectoxin) family. 01 (Tx3)
CC       subfamily. {ECO:0000305}.
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DR   AlphaFoldDB; P0C2S6; -.
DR   SMR; P0C2S6; -.
DR   ArachnoServer; AS000260; U9-ctenitoxin-Pn1a.
DR   GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR   GO; GO:0005246; F:calcium channel regulator activity; IEA:UniProtKB-KW.
DR   GO; GO:0008200; F:ion channel inhibitor activity; IEA:InterPro.
DR   GO; GO:0090729; F:toxin activity; IEA:UniProtKB-KW.
DR   CDD; cd12960; Spider_toxin; 1.
DR   InterPro; IPR004169; Spidertoxin.
PE   3: Inferred from homology;
KW   Calcium channel impairing toxin; Disulfide bond;
KW   Ion channel impairing toxin; Knottin; Neurotoxin; Secreted; Signal; Toxin;
KW   Voltage-gated calcium channel impairing toxin.
FT   SIGNAL          1..22
FT                   /evidence="ECO:0000255"
FT   PROPEP          23..37
FT                   /evidence="ECO:0000250"
FT                   /id="PRO_0000284871"
FT   CHAIN           39..74
FT                   /note="U9-ctenitoxin-Pn1a"
FT                   /id="PRO_0000284872"
FT   PROPEP          75..87
FT                   /evidence="ECO:0000250"
FT                   /id="PRO_0000284873"
FT   DISULFID        40..54
FT                   /evidence="ECO:0000250|UniProtKB:P30288"
FT   DISULFID        47..64
FT                   /evidence="ECO:0000250|UniProtKB:P30288"
FT   DISULFID        53..73
FT                   /evidence="ECO:0000250|UniProtKB:P30288"
FT   DISULFID        66..71
FT                   /evidence="ECO:0000250|UniProtKB:P30288"
SQ   SEQUENCE   87 AA;  9559 MW;  4D1629BFC0FC33FE CRC64;
     MWLKTQLFVL AIAVIALLEV HAEPESNDNN ELVVEEARGC ADAYKSCNHP RTCCDGYNGY
     KRACICSGSN CKCKKSLREM AAAAFGR