ID   TXHN2_GRARO             Reviewed;          35 AA.
AC   P56853;
DT   30-MAY-2000, integrated into UniProtKB/Swiss-Prot.
DT   30-MAY-2000, sequence version 1.
DT   25-MAY-2022, entry version 65.
DE   RecName: Full=Kappa-theraphotoxin-Gr1b;
DE            Short=Kappa-TRTX-Gr1b;
DE   AltName: Full=Hanatoxin-2 {ECO:0000303|PubMed:7576642};
DE            Short=HaTx2 {ECO:0000303|PubMed:7576642};
OS   Grammostola rosea (Chilean rose tarantula) (Grammostola spatulata).
OC   Eukaryota; Metazoa; Ecdysozoa; Arthropoda; Chelicerata; Arachnida; Araneae;
OC   Mygalomorphae; Theraphosidae; Grammostola.
OX   NCBI_TaxID=432528;
RN   [1]
RP   PROTEIN SEQUENCE.
RC   TISSUE=Venom;
RX   PubMed=7576642; DOI=10.1016/0896-6273(95)90184-1;
RA   Swartz K.J., MacKinnon R.;
RT   "An inhibitor of the Kv2.1 potassium channel isolated from the venom of a
RT   Chilean tarantula.";
RL   Neuron 15:941-949(1995).
CC   -!- FUNCTION: Inhibitor of voltage-gated potassium channels. Inhibits
CC       Kv2.1/KCNB1 channels, by shifting activation of the channel to more
CC       depolarized voltages. The toxin binding sites may be situated on the
CC       S3-S4 extracellular linker of the channel. One, two, three or four
CC       toxin molecules may bind the Kv2.1/KCNB1 channel. May need to partition
CC       into the membrane in order to bind to the channel. Antibacterial
CC       activity is not observed.
CC   -!- SUBCELLULAR LOCATION: Secreted.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC   -!- DOMAIN: The presence of a 'disulfide through disulfide knot'
CC       structurally defines this protein as a knottin. {ECO:0000250}.
CC   -!- SIMILARITY: Belongs to the neurotoxin 10 (Hwtx-1) family. 09 (HaTx)
CC       subfamily. {ECO:0000305}.
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DR   AlphaFoldDB; P56853; -.
DR   SMR; P56853; -.
DR   ArachnoServer; AS000343; kappa-theraphotoxin-Gr1b.
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-Gr1b"
FT                   /id="PRO_0000045013"
FT   REGION          4..6
FT                   /note="Involved in active face"
FT                   /evidence="ECO:0000250"
FT   SITE            3
FT                   /note="May be involved in interaction with voltage sensor"
FT                   /evidence="ECO:0000250"
FT   SITE            22
FT                   /note="May be involved in interaction with voltage sensor"
FT                   /evidence="ECO:0000250"
FT   SITE            30
FT                   /note="Involved in active face"
FT                   /evidence="ECO:0000250"
FT   DISULFID        2..16
FT                   /evidence="ECO:0000250"
FT   DISULFID        9..21
FT                   /evidence="ECO:0000250"
FT   DISULFID        15..28
FT                   /evidence="ECO:0000250"
SQ   SEQUENCE   35 AA;  4105 MW;  5601AC8A9B14C513 CRC64;
     ECRYLFGGCK TTADCCKHLG CKFRDKYCAW DFTFS