ID   KA12O_SCOPC             Reviewed;          55 AA.
AC   P0DQN5;
DT   02-DEC-2020, integrated into UniProtKB/Swiss-Prot.
DT   02-DEC-2020, sequence version 1.
DT   25-MAY-2022, entry version 6.
DE   RecName: Full=Potassium channel toxin alpha-KTX 12 Sp2 {ECO:0000305};
DE            Short=KTX-Sp2 {ECO:0000303|PubMed:31890149};
DE   Flags: Precursor;
OS   Scorpiops pococki (Scorpion).
OC   Eukaryota; Metazoa; Ecdysozoa; Arthropoda; Chelicerata; Arachnida;
OC   Scorpiones; Iurida; Chactoidea; Euscorpiidae; Scorpiopinae; Scorpiopini;
OC   Scorpiops.
OX   NCBI_TaxID=2766750;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA], AND FUNCTION.
RC   TISSUE=Venom gland;
RX   PubMed=31890149; DOI=10.1186/s13578-019-0364-1;
RA   Zhang Y., Zhang F., Shi S., Liu X., Cai W., Han G., Ke C., Long S., Di Z.,
RA   Yin S., Li H.;
RT   "Immunosuppressive effects of a novel potassium channel toxin Ktx-Sp2 from
RT   Scorpiops Pocoki.";
RL   Cell Biosci. 9:99-99(2019).
CC   -!- FUNCTION: Blocks mouse voltage-gated potassium channels Kv1.3/KCNA3
CC       (IC(50)=0.3-30 nM), when the channel is expressed in Jurkat T cells or
CC       in HEK293 cells (PubMed:31890149). Also shows a weaker inhibition on
CC       mKv1.2/KCNA2 (IC(50)=56.9 nM) and mKv1.1/KCNA1 (IC(50)=485 nM)
CC       (PubMed:31890149). Probably through the inhibition of both Kv1.2/KCNA2
CC       and Kv1.3/KCNA3, the toxin also reduces the free calcium concentration
CC       in Jurkat T cells, inhibits the activation of Jurkat T cells and
CC       reduces the release of inflammatory cytokines interleukin-2, showing a
CC       strong immunosuppressant effect (PubMed:31890149).
CC       {ECO:0000269|PubMed:31890149}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000269|PubMed:31890149}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC       {ECO:0000305|PubMed:31890149}.
CC   -!- DOMAIN: Has the structural arrangement of an alpha-helix connected to a
CC       beta-sheet by disulfide bonds (CSalpha/beta).
CC       {ECO:0000250|UniProtKB:P40755}.
CC   -!- MISCELLANEOUS: Does not block voltage-gated sodium channels
CC       Nav1.4/SCN4A, Nav1.5/SCN5A, and Nav1.7/SCN9A.
CC       {ECO:0000269|PubMed:31890149}.
CC   -!- SIMILARITY: Belongs to the short scorpion toxin superfamily. Potassium
CC       channel inhibitor family. Alpha-KTx 12 subfamily. {ECO:0000305}.
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DR   AlphaFoldDB; P0DQN5; -.
DR   SMR; P0DQN5; -.
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   Gene3D; 3.30.30.10; -; 1.
DR   InterPro; IPR036574; Scorpion_toxin-like_sf.
DR   InterPro; IPR001947; Scorpion_toxinS_K_inh.
DR   Pfam; PF00451; Toxin_2; 1.
DR   PRINTS; PR00286; CHARYBDTOXIN.
DR   SUPFAM; SSF57095; SSF57095; 1.
PE   3: Inferred from homology;
KW   Disulfide bond; Ion channel impairing toxin; Neurotoxin;
KW   Potassium channel impairing toxin; Secreted; Signal; Toxin;
KW   Voltage-gated potassium channel impairing toxin.
FT   SIGNAL          1..18
FT                   /evidence="ECO:0000305|PubMed:31890149"
FT   CHAIN           19..55
FT                   /note="Potassium channel toxin alpha-KTX 12 Sp2"
FT                   /evidence="ECO:0000305|PubMed:31890149"
FT                   /id="PRO_0000451630"
FT   DISULFID        26..46
FT                   /evidence="ECO:0000250|UniProtKB:O46028"
FT   DISULFID        32..51
FT                   /evidence="ECO:0000250|UniProtKB:O46028"
FT   DISULFID        36..53
FT                   /evidence="ECO:0000250|UniProtKB:O46028"
SQ   SEQUENCE   55 AA;  5902 MW;  759ED970E01C3957 CRC64;
     MRLAIILLLM TTIVLTIGSP LHGAKCSSSN QCTRPCRYGG GTHGKCMNGR CRCYG