ID   TX21_PHOKE              Reviewed;          32 AA.
AC   P83915;
DT   19-JUL-2004, integrated into UniProtKB/Swiss-Prot.
DT   24-MAY-2004, sequence version 1.
DT   25-MAY-2022, entry version 39.
DE   RecName: Full=U3-ctenitoxin-Pk1a;
DE            Short=U3-CNTX-Pk1a;
DE   AltName: Full=Neurotoxin PKTx21C2 {ECO:0000303|PubMed:16278100};
DE   Contains:
DE     RecName: Full=Neurotoxin PKTx21C2 variant Ala-1 Del {ECO:0000303|Ref.2};
OS   Phoneutria keyserlingi (Brazilian wandering spider) (Ctenus keyserlingii).
OC   Eukaryota; Metazoa; Ecdysozoa; Arthropoda; Chelicerata; Arachnida; Araneae;
OC   Araneomorphae; Entelegynae; Lycosoidea; Ctenidae; Phoneutria.
OX   NCBI_TaxID=272754;
RN   [1]
RP   PROTEIN SEQUENCE, SUBCELLULAR LOCATION, AND MASS SPECTROMETRY.
RC   TISSUE=Venom;
RX   PubMed=16278100; DOI=10.1016/j.cbpc.2005.09.010;
RA   Richardson M., Pimenta A.M., Bemquerer M.P., Santoro M.M., Beirao P.S.,
RA   Lima M.E., Figueiredo S.G., Bloch C. Jr., Vasconcelos E.A., Campos F.A.,
RA   Gomes P.C., Cordeiro M.N.;
RT   "Comparison of the partial proteomes of the venoms of Brazilian spiders of
RT   the genus Phoneutria.";
RL   Comp. Biochem. Physiol. 142:173-187(2006).
RN   [2]
RP   PROTEIN SEQUENCE, MASS SPECTROMETRY, VARIANT ALA-1 DEL, AND SUBCELLULAR
RP   LOCATION.
RC   TISSUE=Venom;
RA   Richardson M., Pimenta A.M.C., Bemquerer M.P., Santoro M.M.,
RA   Figueiredo S.G., Cordeiro M.N.;
RT   "Neurotoxin PKTx21C2 from venom of Brazilian wandering spider Phoneutria
RT   keyserling.";
RL   Submitted (APR-2004) to UniProtKB.
CC   -!- FUNCTION: May act as a neurotoxin. {ECO:0000305}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000305|PubMed:16278100,
CC       ECO:0000305|Ref.2}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC       {ECO:0000305|PubMed:16278100, ECO:0000305|Ref.2}.
CC   -!- DOMAIN: The presence of a 'disulfide through disulfide knot'
CC       structurally defines this protein as a knottin. {ECO:0000250}.
CC   -!- MASS SPECTROMETRY: [U3-ctenitoxin-Pk1a]: Mass=3478.1;
CC       Method=Electrospray; Evidence={ECO:0000269|PubMed:16278100};
CC   -!- MASS SPECTROMETRY: [Neurotoxin PKTx21C2 variant Ala-1 Del]:
CC       Mass=3407.1; Method=Electrospray; Evidence={ECO:0000269|Ref.2};
CC   -!- SIMILARITY: Belongs to the neurotoxin 17 (21C2) family. {ECO:0000305}.
CC   ---------------------------------------------------------------------------
CC   Copyrighted by the UniProt Consortium, see https://www.uniprot.org/terms
CC   Distributed under the Creative Commons Attribution (CC BY 4.0) License
CC   ---------------------------------------------------------------------------
DR   AlphaFoldDB; P83915; -.
DR   SMR; P83915; -.
DR   ArachnoServer; AS000233; U3-ctenitoxin-Pk1a.
DR   GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR   GO; GO:0090729; F:toxin activity; IEA:UniProtKB-KW.
DR   InterPro; IPR012634; Toxin_29.
DR   Pfam; PF08116; Toxin_29; 1.
PE   1: Evidence at protein level;
KW   Direct protein sequencing; Disulfide bond; Knottin; Neurotoxin; Secreted;
KW   Toxin.
FT   PEPTIDE         1..32
FT                   /note="U3-ctenitoxin-Pk1a"
FT                   /evidence="ECO:0000269|PubMed:16278100"
FT                   /id="PRO_0000044971"
FT   PEPTIDE         2..32
FT                   /note="Neurotoxin PKTx21C2 variant Ala-1 Del"
FT                   /evidence="ECO:0000269|Ref.2"
FT                   /id="PRO_0000447872"
FT   DISULFID        3..17
FT                   /evidence="ECO:0000250"
FT   DISULFID        10..21
FT                   /evidence="ECO:0000250"
FT   DISULFID        16..30
FT                   /evidence="ECO:0000250"
SQ   SEQUENCE   32 AA;  3484 MW;  2A38152A6765DE74 CRC64;
     AFCKYNGEQC TSDGQCCNGR CRTAFMGKIC MG