ID   TX21A_PHORI             Reviewed;          40 AA.
AC   P83909;
DT   19-JUL-2004, integrated into UniProtKB/Swiss-Prot.
DT   19-JAN-2010, sequence version 2.
DT   25-MAY-2022, entry version 39.
DE   RecName: Full=U2-ctenitoxin-Pr1a {ECO:0000305};
DE            Short=U2-CNTX-Pr1a {ECO:0000305};
DE   AltName: Full=Neurotoxin PRTx22C1 {ECO:0000303|PubMed:16278100};
OS   Phoneutria reidyi (Brazilian Amazonian armed spider) (Ctenus reidyi).
OC   Eukaryota; Metazoa; Ecdysozoa; Arthropoda; Chelicerata; Arachnida; Araneae;
OC   Araneomorphae; Entelegynae; Lycosoidea; Ctenidae; Phoneutria.
OX   NCBI_TaxID=272752 {ECO:0000305};
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).
CC   -!- FUNCTION: Neurotoxin. {ECO:0000305}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000269|PubMed:16278100}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC       {ECO:0000305|PubMed:16278100}.
CC   -!- DOMAIN: The presence of a 'disulfide through disulfide knot'
CC       structurally defines this protein as a knottin.
CC       {ECO:0000250|UniProtKB:P30288}.
CC   -!- MASS SPECTROMETRY: Mass=4546.2; Method=Electrospray;
CC       Evidence={ECO:0000269|PubMed:16278100, ECO:0000305};
CC   -!- SIMILARITY: Belongs to the neurotoxin 02 (plectoxin) family. 01 (Tx3)
CC       subfamily. {ECO:0000305}.
CC   -!- CAUTION: While it is structurally defined as a knottin it lacks the
CC       conserved Cys residue in position 9. {ECO:0000305}.
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DR   AlphaFoldDB; P83909; -.
DR   SMR; P83909; -.
DR   ArachnoServer; AS000237; U2-ctenitoxin-Pr1a.
DR   GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
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.
DR   Pfam; PF02819; Toxin_9; 1.
PE   1: Evidence at protein level;
KW   Direct protein sequencing; Disulfide bond; Knottin; Neurotoxin; Secreted;
KW   Toxin.
FT   PEPTIDE         1..40
FT                   /note="U2-ctenitoxin-Pr1a"
FT                   /evidence="ECO:0000303|PubMed:16278100"
FT                   /id="PRO_0000044970"
FT   DISULFID        2..17
FT                   /evidence="ECO:0000250|UniProtKB:P30288"
FT   DISULFID        9..22
FT                   /evidence="ECO:0000250|UniProtKB:P30288"
FT   DISULFID        16..32
FT                   /evidence="ECO:0000250|UniProtKB:P30288"
FT   DISULFID        24..30
FT                   /evidence="ECO:0000250|UniProtKB:P30288"
SQ   SEQUENCE   40 AA;  4554 MW;  D812D0BFA2A6B7EC CRC64;
     ECADVYKECW YPEKPCCKDR ACQCSLGMNC KCKATLGDIF