ID   TXP2_PARSR              Reviewed;          31 AA.
AC   P61231;
DT   10-MAY-2004, integrated into UniProtKB/Swiss-Prot.
DT   10-MAY-2004, sequence version 1.
DT   25-MAY-2022, entry version 56.
DE   RecName: Full=Kappa-theraphotoxin-Ps1b {ECO:0000305};
DE            Short=Kappa-TRTX-Ps1b {ECO:0000305};
DE   AltName: Full=PaTX2 {ECO:0000303|PubMed:10051143};
DE   AltName: Full=Phrixotoxin-2 {ECO:0000303|PubMed:10051143};
OS   Paraphysa scrofa (Chilean copper tarantula) (Phrixotrichus auratus).
OC   Eukaryota; Metazoa; Ecdysozoa; Arthropoda; Chelicerata; Arachnida; Araneae;
OC   Mygalomorphae; Theraphosidae; Paraphysa.
OX   NCBI_TaxID=269635;
RN   [1]
RP   PROTEIN SEQUENCE, FUNCTION, AMIDATION AT MET-31, MASS SPECTROMETRY, AND
RP   SUBCELLULAR LOCATION.
RX   PubMed=10051143; DOI=10.1038/sj.bjp.0702283;
RA   Diochot S., Drici M.-D., Moinier D., Fink M., Lazdunski M.;
RT   "Effects of phrixotoxins on the Kv4 family of potassium channels and
RT   implications for the role of Ito1 in cardiac electrogenesis.";
RL   Br. J. Pharmacol. 126:251-263(1999).
CC   -!- FUNCTION: Potent and specific blocker of Kv4.2/KCND2 (IC(50)=34 nM) and
CC       Kv4.3/KCND3 (IC(50)=71 nM) potassium channels (PubMed:10051143). Acts
CC       by altering the gating properties of these channels (PubMed:10051143).
CC       {ECO:0000269|PubMed:10051143}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000269|PubMed:10051143}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC       {ECO:0000305|PubMed:10051143}.
CC   -!- DOMAIN: The presence of a 'disulfide through disulfide knot'
CC       structurally defines this protein as a knottin.
CC       {ECO:0000250|UniProtKB:P61230}.
CC   -!- MASS SPECTROMETRY: Mass=3921.77; Method=Electrospray;
CC       Evidence={ECO:0000269|PubMed:10051143};
CC   -!- MISCELLANEOUS: The primary structure of this mature peptide is
CC       identical to that of kappa-theraphotoxin-Gr2a (GsMTx-2) from
CC       Grammostola rosea (AC P60273). {ECO:0000305}.
CC   -!- MISCELLANEOUS: Is the most abundant peptide in the venom.
CC       {ECO:0000269|PubMed:10051143}.
CC   -!- MISCELLANEOUS: This toxin does not inhibit Kv1/KCNA, Kv2/KCNB,
CC       Kv3/KCNC, and Kv11/KCNH channels (PubMed:10051143). It weakly blocks
CC       the neuronal TTX-sensitive sodium currents of neuroblastoma cells (14%
CC       inhibition at 500 nM) (PubMed:10051143). {ECO:0000269|PubMed:10051143}.
CC   -!- SIMILARITY: Belongs to the neurotoxin 30 (phrixotoxin) family.
CC       {ECO:0000305}.
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DR   AlphaFoldDB; P61231; -.
DR   SMR; P61231; -.
DR   ArachnoServer; AS000402; kappa-theraphotoxin-Ps1b.
DR   GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR   GO; GO:0015459; F:potassium channel regulator activity; IEA:UniProtKB-KW.
DR   GO; GO:0090729; F:toxin activity; IEA:UniProtKB-KW.
PE   1: Evidence at protein level;
KW   Amidation; Direct protein sequencing; Disulfide bond;
KW   Ion channel impairing toxin; Knottin; Neurotoxin;
KW   Potassium channel impairing toxin; Secreted; Toxin;
KW   Voltage-gated potassium channel impairing toxin.
FT   PEPTIDE         1..31
FT                   /note="Kappa-theraphotoxin-Ps1b"
FT                   /evidence="ECO:0000269|PubMed:10051143"
FT                   /id="PRO_0000045023"
FT   MOD_RES         31
FT                   /note="Methionine amide"
FT                   /evidence="ECO:0000305|PubMed:10051143"
FT   DISULFID        2..16
FT                   /evidence="ECO:0000250|UniProtKB:P60273"
FT   DISULFID        9..21
FT                   /evidence="ECO:0000250|UniProtKB:P60273"
FT   DISULFID        15..25
FT                   /evidence="ECO:0000250|UniProtKB:P60273"
SQ   SEQUENCE   31 AA;  3929 MW;  AAECBB87A92AAC1B CRC64;
     YCQKWMWTCD EERKCCEGLV CRLWCKRIIN M