ID   KKX25_OPICY             Reviewed;          70 AA.
AC   P86110; C5J892;
DT   05-OCT-2010, integrated into UniProtKB/Swiss-Prot.
DT   05-OCT-2010, sequence version 1.
DT   25-MAY-2022, entry version 23.
DE   RecName: Full=Potassium channel toxin kappa-KTx 2.5 {ECO:0000303|PubMed:21624408};
DE   AltName: Full=OcyC8 {ECO:0000303|PubMed:19379768};
DE   AltName: Full=OcyKTx6;
DE   Flags: Precursor;
OS   Opisthacanthus cayaporum (South American scorpion).
OC   Eukaryota; Metazoa; Ecdysozoa; Arthropoda; Chelicerata; Arachnida;
OC   Scorpiones; Iurida; Scorpionoidea; Hemiscorpiidae; Opisthacanthus.
OX   NCBI_TaxID=573324;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA].
RC   TISSUE=Venom gland;
RX   PubMed=19379768; DOI=10.1016/j.toxicon.2009.04.010;
RA   Silva E.C., Camargos T.S., Maranhao A.Q., Silva-Pereira I., Silva L.P.,
RA   Possani L.D., Schwartz E.F.;
RT   "Cloning and characterization of cDNA sequences encoding for new venom
RT   peptides of the Brazilian scorpion Opisthacanthus cayaporum.";
RL   Toxicon 54:252-261(2009).
RN   [2]
RP   PROTEIN SEQUENCE OF 43-70, FUNCTION, SUBCELLULAR LOCATION, SYNTHESIS OF
RP   43-70, DOMAIN, CIRCULAR DICHROISM, AND MASS SPECTROMETRY.
RC   TISSUE=Venom;
RX   PubMed=21624408; DOI=10.1016/j.peptides.2011.05.017;
RA   Camargos T.S., Restano-Cassulini R., Possani L.D., Peigneur S., Tytgat J.,
RA   Schwartz C.A., Alves E.M., de Freitas S.M., Schwartz E.F.;
RT   "The new kappa-KTx 2.5 from the scorpion Opisthacanthus cayaporum.";
RL   Peptides 32:1509-1517(2011).
RN   [3]
RP   PROTEIN SEQUENCE OF 43-64, SUBCELLULAR LOCATION, AND IDENTIFICATION BY MASS
RP   SPECTROMETRY.
RC   TISSUE=Venom;
RX   PubMed=18502464; DOI=10.1016/j.toxicon.2008.03.029;
RA   Schwartz E.F., Camargos T.S., Zamudio F.Z., Silva L.P., Bloch C. Jr.,
RA   Caixeta F., Schwartz C.A., Possani L.D.;
RT   "Mass spectrometry analysis, amino acid sequence and biological activity of
RT   venom components from the Brazilian scorpion Opisthacanthus cayaporum.";
RL   Toxicon 51:1499-1508(2008).
CC   -!- FUNCTION: Voltage-independently blocks potassium currents on
CC       hKv1.1/KCNA1 (IC(50)=217 uM), and hKv1.4/KCNA4 (IC(50)=71 uM)
CC       (expressed in CHO cells). {ECO:0000269|PubMed:21624408}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000269|PubMed:18502464,
CC       ECO:0000269|PubMed:21624408}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC       {ECO:0000305|PubMed:18502464, ECO:0000305|PubMed:21624408}.
CC   -!- DOMAIN: Has the structural arrangement of two alpha-helices stabilized
CC       by disulfide bonds (CSalpha/alpha 2(S-S)).
CC       {ECO:0000250|UniProtKB:P0C1Z3}.
CC   -!- MASS SPECTROMETRY: Mass=3132.26; Method=MALDI; Note=Monoisotopic mass.;
CC       Evidence={ECO:0000269|PubMed:21624408};
CC   -!- MISCELLANEOUS: Has no effect on other potassium channels, on sodium
CC       channels, on bacterial growth and on smooth muscle tissue (a known
CC       assay to identify possible bradykinin-potentiating peptides).
CC       {ECO:0000305|PubMed:21624408}.
CC   -!- SIMILARITY: Belongs to the short scorpion toxin superfamily. Potassium
CC       channel inhibitor kappa-KTx family. Kappa-KTx 2 subfamily.
CC       {ECO:0000305}.
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DR   EMBL; FM998750; CAX51396.1; -; mRNA.
DR   AlphaFoldDB; P86110; -.
DR   SMR; P86110; -.
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   Direct protein sequencing; Disulfide bond; Ion channel impairing toxin;
KW   Neurotoxin; Potassium channel impairing toxin; Secreted; Signal; Toxin;
KW   Voltage-gated potassium channel impairing toxin.
FT   SIGNAL          1..26
FT                   /evidence="ECO:0000255"
FT   PROPEP          27..42
FT                   /evidence="ECO:0000269|PubMed:18502464,
FT                   ECO:0000269|PubMed:21624408"
FT                   /id="PRO_0000398603"
FT   PEPTIDE         43..70
FT                   /note="Potassium channel toxin kappa-KTx 2.5"
FT                   /evidence="ECO:0000303|PubMed:21624408"
FT                   /id="PRO_0000398136"
FT   DISULFID        46..64
FT                   /evidence="ECO:0000250|UniProtKB:P0C1Z3"
FT   DISULFID        50..60
FT                   /evidence="ECO:0000250|UniProtKB:P0C1Z3"
FT   CONFLICT        53
FT                   /note="H -> N (in Ref. 3; AA sequence)"
FT                   /evidence="ECO:0000305"
SQ   SEQUENCE   70 AA;  7823 MW;  152071A7A97408C5 CRC64;
     MESSRKSYVL MLFLAFVIMN VCSVSGEPKD GEIAGFEMEE ARYDACVNAC LEHHPNVREC
     EEACKNPVPP