ID   TX20C_PHONI             Reviewed;          84 AA.
AC   P81791;
DT   23-JAN-2002, integrated into UniProtKB/Swiss-Prot.
DT   01-MAY-2007, sequence version 2.
DT   25-MAY-2022, entry version 49.
DE   RecName: Full=U7-ctenitoxin-Pn1a;
DE            Short=U7-CNTX-Pn1a;
DE   AltName: Full=Neurotoxin Tx3-5;
DE   AltName: Full=PnTx3-5;
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).
RN   [2]
RP   PROTEIN SEQUENCE OF 40-84, SUBCELLULAR LOCATION, TISSUE SPECIFICITY, AND
RP   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   [3]
RP   PROTEIN SEQUENCE OF 40-75.
RC   TISSUE=Venom;
RX   PubMed=8446961; DOI=10.1016/0041-0101(93)90354-l;
RA   Cordeiro M.N., De Figueiredo S.G., Valentim A.D.C., Diniz C.R.,
RA   von Eickstedt V.R.D., Gilroy J., Richardson M.;
RT   "Purification and amino acid sequences of six Tx3 type neurotoxins from the
RT   venom of the Brazilian 'armed' spider Phoneutria nigriventer (Keys).";
RL   Toxicon 31:35-42(1993).
CC   -!- FUNCTION: Antagonist of L-type calcium channels (Cav1/CACNA1). Causes
CC       paralysis in the posterior limbs and gradual decreases in movement and
CC       aggression during 24 hours at dose levels of 5 ug per mouse.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000269|PubMed:16278100}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC       {ECO:0000269|PubMed:16278100}.
CC   -!- DOMAIN: The presence of a 'disulfide through disulfide knot'
CC       structurally defines this protein as a knottin. {ECO:0000250}.
CC   -!- MASS SPECTROMETRY: Mass=5063.6; Method=Unknown;
CC       Evidence={ECO:0000269|PubMed:16278100};
CC   -!- SIMILARITY: Belongs to the neurotoxin 02 (plectoxin) family.
CC       {ECO:0000305}.
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DR   PIR; E44336; E44336.
DR   AlphaFoldDB; P81791; -.
DR   SMR; P81791; -.
DR   ArachnoServer; AS000265; U7-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:0090729; F:toxin activity; IEA:UniProtKB-KW.
DR   InterPro; IPR019553; Spider_toxin_CSTX_knottin.
DR   Pfam; PF10530; Toxin_35; 1.
PE   1: Evidence at protein level;
KW   Calcium channel impairing toxin; Direct protein sequencing; Disulfide bond;
KW   Ion channel impairing toxin; Knottin; Neurotoxin; Secreted; Signal; Toxin;
KW   Voltage-gated calcium channel impairing toxin.
FT   SIGNAL          1..17
FT                   /evidence="ECO:0000255"
FT   PROPEP          18..38
FT                   /id="PRO_0000285664"
FT   CHAIN           40..84
FT                   /note="U7-ctenitoxin-Pn1a"
FT                   /id="PRO_0000087640"
FT   DISULFID        41..56
FT                   /evidence="ECO:0000250"
FT   DISULFID        48..61
FT                   /evidence="ECO:0000250"
FT   DISULFID        55..78
FT                   /evidence="ECO:0000250"
FT   DISULFID        63..76
FT                   /evidence="ECO:0000250"
SQ   SEQUENCE   84 AA;  9530 MW;  B5E93D048A8E773E CRC64;
     MKLCILLVVL LITVVRAEED ILENEAEDIS PAIKERSARG CIGRNESCKF DRHGCCWPWS
     CSCWNKEGQP ESDVWCECSL KIGK