ID   KA20X_TITTR             Reviewed;          28 AA.
AC   B3A0L5; H2L2L5;
DT   16-MAY-2012, integrated into UniProtKB/Swiss-Prot.
DT   16-MAY-2012, sequence version 1.
DT   25-MAY-2022, entry version 22.
DE   RecName: Full=Kappa-buthitoxin-Tt2b {ECO:0000303|PubMed:22238341};
DE            Short=Kappa-BUTX-Tt2b {ECO:0000303|PubMed:22238341};
OS   Tityus trivittatus (Argentinean scorpion).
OC   Eukaryota; Metazoa; Ecdysozoa; Arthropoda; Chelicerata; Arachnida;
OC   Scorpiones; Buthida; Buthoidea; Buthidae; Tityus.
OX   NCBI_TaxID=369776;
RN   [1]
RP   PROTEIN SEQUENCE, FUNCTION, SUBCELLULAR LOCATION, DOMAIN, MASS
RP   SPECTROMETRY, DISULFIDE BONDS, AND STRUCTURE BY NMR.
RC   TISSUE=Venom {ECO:0000269|PubMed:22238341};
RX   PubMed=22238341; DOI=10.1074/jbc.m111.329607;
RA   Saucedo A.L., Flores-Solis D., Rodriguez de la Vega R.C.,
RA   Ramirez-Cordero B., Hernandez-Lopez R., Cano-Sanchez P.,
RA   Noriega-Navarro R., Garcia-Valdes J., Coronas-Valderrama F., de Roodt A.,
RA   Brieba L.G., Possani L.D., Del Rio-Portilla F.;
RT   "New tricks of an old pattern: structural versatility of scorpion toxins
RT   with common cysteine spacing.";
RL   J. Biol. Chem. 287:12321-12330(2012).
CC   -!- FUNCTION: Blocks potassium channels Shaker-IR (with inactivation domain
CC       removed) and hKv1.2/KCNA2. {ECO:0000269|PubMed:22238341}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000269|PubMed:22238341}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland. {ECO:0000305}.
CC   -!- DOMAIN: Has the structural arrangement of two alpha-helices stabilized
CC       by disulfide bonds (CSalpha/alpha 3(S-S)).
CC       {ECO:0000269|PubMed:22238341}.
CC   -!- MASS SPECTROMETRY: Mass=3179.75; Method=MALDI;
CC       Evidence={ECO:0000269|PubMed:22238341};
CC   -!- SIMILARITY: Belongs to the short scorpion toxin superfamily. Potassium
CC       channel inhibitor family. Alpha-KTx 20 subfamily. {ECO:0000255}.
CC   -!- CAUTION: The sequence aligns with alpha-KTx but has the CSalpha/alpha
CC       scaffold of a kappa-KTx due to the unusual pattern of disulfide bonds.
CC       As is the method of choice in UniProtKB, the assignment to the alpha-
CC       KTx 20 subfamily is based purely on the primary structure.
CC       {ECO:0000305}.
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DR   PDB; 2LI3; NMR; -; A=1-28.
DR   PDBsum; 2LI3; -.
DR   AlphaFoldDB; B3A0L5; -.
DR   BMRB; B3A0L5; -.
DR   SMR; B3A0L5; -.
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   3D-structure; Direct protein sequencing; Disulfide bond;
KW   Ion channel impairing toxin; Neurotoxin; Potassium channel impairing toxin;
KW   Secreted; Toxin.
FT   PEPTIDE         1..28
FT                   /note="Kappa-buthitoxin-Tt2b"
FT                   /evidence="ECO:0000269|PubMed:22238341"
FT                   /id="PRO_0000417398"
FT   DISULFID        2..24
FT                   /evidence="ECO:0000269|PubMed:22238341"
FT   DISULFID        7..20
FT                   /evidence="ECO:0000269|PubMed:22238341"
FT   DISULFID        11..26
FT                   /evidence="ECO:0000269|PubMed:22238341"
FT   HELIX           4..10
FT                   /evidence="ECO:0007829|PDB:2LI3"
FT   HELIX           15..23
FT                   /evidence="ECO:0007829|PDB:2LI3"
SQ   SEQUENCE   28 AA;  3186 MW;  76618F0DC13D304C CRC64;
     GCMPEYCAGQ CRGKVSQDYC LKNCRCIR