ID   TX1_STRCF               Reviewed;          34 AA.
AC   P60991;
DT   26-APR-2004, integrated into UniProtKB/Swiss-Prot.
DT   26-APR-2004, sequence version 1.
DT   25-MAY-2022, entry version 57.
DE   RecName: Full=Kappa-theraphotoxin-Sc1a;
DE            Short=Kappa-TRTX-Sc1a;
DE   AltName: Full=Stromatoxin-1 {ECO:0000303|PubMed:12065754};
DE            Short=ScTx1 {ECO:0000303|PubMed:12065754};
OS   Stromatopelma calceatum (Featherleg baboon tarantula) (Scodra calceata).
OC   Eukaryota; Metazoa; Ecdysozoa; Arthropoda; Chelicerata; Arachnida; Araneae;
OC   Mygalomorphae; Theraphosidae; Stromatopelma.
OX   NCBI_TaxID=269628;
RN   [1]
RP   PROTEIN SEQUENCE, FUNCTION, AMIDATION AT ILE-34, MASS SPECTROMETRY, AND
RP   3D-STRUCTURE MODELING.
RC   TISSUE=Venom;
RX   PubMed=12065754; DOI=10.1124/mol.62.1.48;
RA   Escoubas P., Diochot S., Celerier M.-L., Nakajima T., Lazdunski M.;
RT   "Novel tarantula toxins for subtypes of voltage-dependent potassium
RT   channels in the Kv2 and Kv4 subfamilies.";
RL   Mol. Pharmacol. 62:48-57(2002).
CC   -!- FUNCTION: Acts as a gating-modifier to inhibit voltage-gated potassium
CC       channels. It inhibits delayed Kv2.1/KCNB1 (IC(50) is 12.7 nM),
CC       Kv2.1/Kv9.3 (IC(50) is 7.2 nM) (KCNB1/KCNS3), Kv2.2/KCNB2 (IC(50) is
CC       21.4 nM), and transient Kv4.2/KCND2 (IC(50) is 1.2 nM) channels.
CC       {ECO:0000269|PubMed:12065754}.
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   -!- MASS SPECTROMETRY: Mass=3788.62; Method=MALDI;
CC       Evidence={ECO:0000269|PubMed:12065754};
CC   -!- MISCELLANEOUS: This toxin does not have effect on Kv4.1/KCND1 and
CC       Kv4.3/KCND3. Intracerebroventricular injection into mice does not
CC       induce observable neurotoxicity symptoms (PubMed:12065754).
CC       {ECO:0000305|PubMed:12065754}.
CC   -!- SIMILARITY: Belongs to the neurotoxin 10 (Hwtx-1) family. 57 (ScTx1)
CC       subfamily. {ECO:0000305}.
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DR   AlphaFoldDB; P60991; -.
DR   SMR; P60991; -.
DR   ArachnoServer; AS000228; kappa-theraphotoxin-Sc1a.
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   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..34
FT                   /note="Kappa-theraphotoxin-Sc1a"
FT                   /id="PRO_0000045025"
FT   MOD_RES         34
FT                   /note="Isoleucine amide"
FT                   /evidence="ECO:0000269|PubMed:12065754"
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   34 AA;  3798 MW;  20C682CC0CDA14CE CRC64;
     DCTRMFGACR RDSDCCPHLG CKPTSKYCAW DGTI