ID   TX2_THEBL               Reviewed;          35 AA.
AC   P83746;
DT   16-FEB-2004, integrated into UniProtKB/Swiss-Prot.
DT   02-FEB-2004, sequence version 1.
DT   25-MAY-2022, entry version 56.
DE   RecName: Full=Kappa-theraphotoxin-Tb1b;
DE            Short=Kappa-TRTX-Tb1b;
DE   AltName: Full=Theraphotoxin-2;
DE   AltName: Full=TlTx2 {ECO:0000303|PubMed:15150824, ECO:0000303|PubMed:15208026};
OS   Theraphosa blondi (Goliath birdeating spider).
OC   Eukaryota; Metazoa; Ecdysozoa; Arthropoda; Chelicerata; Arachnida; Araneae;
OC   Mygalomorphae; Theraphosidae; Theraphosa.
OX   NCBI_TaxID=260533;
RN   [1]
RP   PROTEIN SEQUENCE, FUNCTION, AND MASS SPECTROMETRY.
RC   TISSUE=Venom;
RX   PubMed=15150824; DOI=10.1002/rcm.1442;
RA   Legros C., Celerier M.-L., Henry M., Guette C.;
RT   "Nanospray analysis of the venom of the tarantula Theraphosa leblondi: a
RT   powerful method for direct venom mass fingerprinting and toxin
RT   sequencing.";
RL   Rapid Commun. Mass Spectrom. 18:1024-1032(2004).
RN   [2]
RP   FUNCTION, AND MASS SPECTROMETRY.
RC   TISSUE=Venom;
RX   PubMed=15208026; DOI=10.1016/j.toxicon.2003.12.012;
RA   Ebbinghaus J., Legros C., Nolting A., Guette C., Celerier M.L., Pongs O.,
RA   Bahring R.;
RT   "Modulation of Kv4.2 channels by a peptide isolated from the venom of the
RT   giant bird-eating tarantula Theraphosa leblondi.";
RL   Toxicon 43:923-932(2004).
CC   -!- FUNCTION: Low-affinity blocker of Kv4.2/KCND2 voltage-gated potassium
CC       channels. Is presumed to shift the voltage-dependence of channel
CC       activation to more depolarized potentials and to bind to the S3-S4
CC       linker region of the voltage sensor domain.
CC       {ECO:0000269|PubMed:15150824, ECO:0000269|PubMed:15208026}.
CC   -!- SUBUNIT: Monomer. {ECO:0000305}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000305}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland. {ECO:0000305}.
CC   -!- DOMAIN: The presence of a 'disulfide through disulfide knot'
CC       structurally defines this protein as a knottin. {ECO:0000250}.
CC   -!- MASS SPECTROMETRY: Mass=4195.56; Method=Electrospray;
CC       Evidence={ECO:0000269|PubMed:15150824};
CC   -!- MASS SPECTROMETRY: Mass=4192.90; Method=MALDI; Note=Monoisotopic mass.;
CC       Evidence={ECO:0000269|PubMed:15208026};
CC   -!- SIMILARITY: Belongs to the neurotoxin 10 (Hwtx-1) family. 58 subfamily.
CC       {ECO:0000305}.
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DR   AlphaFoldDB; P83746; -.
DR   SMR; P83746; -.
DR   ArachnoServer; AS000253; kappa-theraphotoxin-Tb1b.
DR   GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR   GO; GO:0008200; F:ion channel inhibitor activity; IEA:InterPro.
DR   GO; GO:0015459; F:potassium channel regulator activity; IEA:UniProtKB-KW.
DR   GO; GO:0090729; F:toxin activity; IEA:UniProtKB-KW.
DR   InterPro; IPR011696; Huwentoxin-1.
DR   Pfam; PF07740; Toxin_12; 1.
PE   1: Evidence at protein level;
KW   Direct protein sequencing; Disulfide bond; Ion channel impairing toxin;
KW   Knottin; Neurotoxin; Potassium channel impairing toxin; Secreted; Toxin;
KW   Voltage-gated potassium channel impairing toxin.
FT   PEPTIDE         1..35
FT                   /note="Kappa-theraphotoxin-Tb1b"
FT                   /id="PRO_0000045027"
FT   DISULFID        3..18
FT                   /evidence="ECO:0000250|UniProtKB:P58426"
FT   DISULFID        10..23
FT                   /evidence="ECO:0000250|UniProtKB:P58426"
FT   DISULFID        17..30
FT                   /evidence="ECO:0000250|UniProtKB:P58426"
SQ   SEQUENCE   35 AA;  4202 MW;  D8DC998402A0BDA0 CRC64;
     DDCLGMFSSC DPKNDKCCPN RVCRSRDQWC KYKLW