ID   TX20A_PHONI             Reviewed;          83 AA.
AC   O76200;
DT   23-JAN-2002, integrated into UniProtKB/Swiss-Prot.
DT   01-NOV-1998, sequence version 1.
DT   25-MAY-2022, entry version 75.
DE   RecName: Full=Kappa-ctenitoxin-Pn1a {ECO:0000305};
DE            Short=Kappa-CNTX-Pn1a {ECO:0000305};
DE   AltName: Full=Neurotoxin Tx3-1 {ECO:0000303|PubMed:10098851, ECO:0000303|PubMed:8446961};
DE   AltName: Full=PNTx3-1;
DE   AltName: Full=PhKv {ECO:0000303|PubMed:21115025};
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], AND FUNCTION.
RX   PubMed=10098851; DOI=10.1046/j.1471-4159.1999.721472.x;
RA   Kushmerick C., Kalapothakis E., Beirao P.S.L., Penaforte C.L., Prado V.F.,
RA   Cruz J.S., Diniz C.R., Cordeiro M.N., Gomez M.V., Romano-Silva M.A.,
RA   Prado M.A.M.;
RT   "Phoneutria nigriventer toxin Tx3-1 blocks A-type K+ currents controlling
RT   Ca2+ oscillation frequency in GH3 cells.";
RL   J. Neurochem. 72:1472-1481(1999).
RN   [2]
RP   PROTEIN SEQUENCE OF 38-77, AND SUBCELLULAR LOCATION.
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).
RN   [3]
RP   PROTEIN SEQUENCE OF 38-77, AND SUBCELLULAR LOCATION.
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   [4]
RP   FUNCTION, AND RECOMBINANT EXPRESSION.
RC   TISSUE=Venom;
RX   PubMed=21115025; DOI=10.1016/j.toxicon.2010.11.013;
RA   Almeida A.P., Andrade A.B., Ferreira A.J., Pires A.C., Damasceno D.D.,
RA   Alves M.N., Gomes E.R., Kushmerick C., Lima R.F., Prado M.A., Prado V.F.,
RA   Richardson M., Cordeiro M.N., Guatimosim S., Gomez M.;
RT   "Antiarrhythmogenic effects of a neurotoxin from the spider Phoneutria
RT   nigriventer.";
RL   Toxicon 57:217-224(2011).
CC   -!- FUNCTION: Antagonist of L-type calcium channels (Cav1/CACNA1)
CC       (PubMed:10098851). In GH3 neuroendocrinal cell line, it reversibly
CC       inhibits the A-type potassium current but does not block other
CC       potassium currents or calcium channels (PubMed:10098851). Shows an
CC       important acetylcholine-mediated antiarrhythmogenic effect in isolated
CC       hearts (PubMed:21115025). In vivo, causes paralysis in the posterior
CC       limbs and gradual decreases in movement and aggression during 24 hours
CC       at dose levels of 5 ug per mouse (PubMed:10098851).
CC       {ECO:0000269|PubMed:10098851, ECO:0000269|PubMed:21115025}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000269|PubMed:16278100,
CC       ECO:0000269|PubMed:8446961}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC       {ECO:0000305|PubMed:16278100, ECO:0000305|PubMed:8446961}.
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.
CC       {ECO:0000305}.
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DR   EMBL; AF015663; AAC26167.1; -; mRNA.
DR   PIR; A44336; A44336.
DR   AlphaFoldDB; O76200; -.
DR   ArachnoServer; AS000255; kappa-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.
DR   Pfam; PF02819; Toxin_9; 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..21
FT                   /evidence="ECO:0000255"
FT   PROPEP          22..37
FT                   /evidence="ECO:0000305|PubMed:8446961"
FT                   /id="PRO_0000035517"
FT   CHAIN           38..77
FT                   /note="Kappa-ctenitoxin-Pn1a"
FT                   /evidence="ECO:0000269|PubMed:8446961"
FT                   /id="PRO_0000035518"
FT   PROPEP          78..83
FT                   /evidence="ECO:0000305|PubMed:8446961"
FT                   /id="PRO_0000035519"
FT   DISULFID        40..55
FT                   /evidence="ECO:0000250|UniProtKB:P30288"
FT   DISULFID        47..60
FT                   /evidence="ECO:0000250|UniProtKB:P30288"
FT   DISULFID        54..71
FT                   /evidence="ECO:0000250|UniProtKB:P30288"
FT   DISULFID        62..69
FT                   /evidence="ECO:0000250|UniProtKB:P30288"
SQ   SEQUENCE   83 AA;  9379 MW;  F1EF6F6F6107C9DC CRC64;
     MWFKIQVLVL AITLITLGIQ AEPNSSPNNP LIVEEDRAEC AAVYERCGKG YKRCCEERPC
     KCNIVMDNCT CKKFISELFG FGK