KAX3J_MESEU
ID KAX3J_MESEU Reviewed; 37 AA.
AC C0HJQ6;
DT 27-MAY-2015, integrated into UniProtKB/Swiss-Prot.
DT 27-MAY-2015, sequence version 1.
DT 25-MAY-2022, entry version 15.
DE RecName: Full=Potassium channel toxin alpha-KTx 3.19 {ECO:0000303|PubMed:25792741};
DE AltName: Full=Toxin MeKTx13-3 {ECO:0000303|PubMed:25792741};
OS Mesobuthus eupeus (Lesser Asian scorpion) (Buthus eupeus).
OC Eukaryota; Metazoa; Ecdysozoa; Arthropoda; Chelicerata; Arachnida;
OC Scorpiones; Buthida; Buthoidea; Buthidae; Mesobuthus.
OX NCBI_TaxID=34648;
RN [1]
RP PROTEIN SEQUENCE, FUNCTION, MASS SPECTROMETRY, SUBCELLULAR LOCATION, AND
RP AMIDATION AT LYS-37.
RC TISSUE=Venom;
RX PubMed=25792741; DOI=10.1074/jbc.m115.637611;
RA Kuzmenkov A.I., Vassilevski A.A., Kudryashova K.S., Nekrasova O.V.,
RA Peigneur S., Tytgat J., Feofanov A.V., Kirpichnikov M.P., Grishin E.V.;
RT "Variability of potassium channel blockers in Mesobuthus eupeus scorpion
RT venom with focus on Kv1.1: an integrated transcriptomic and proteomic
RT study.";
RL J. Biol. Chem. 290:12195-12209(2015).
RN [2]
RP SUBCELLULAR LOCATION, 3D-STRUCTURE MODELING, RECOMBINANT EXPRESSION, AND
RP MUTAGENESIS OF GLN-12; LYS-15; LYS-18 AND ASP-33.
RC TISSUE=Venom;
RX PubMed=32733247; DOI=10.3389/fphar.2020.01010;
RA Gigolaev A.M., Kuzmenkov A.I., Peigneur S., Tabakmakher V.M.,
RA Pinheiro-Junior E.L., Chugunov A.O., Efremov R.G., Tytgat J.,
RA Vassilevski A.A.;
RT "Tuning scorpion toxin selectivity: switching from Kv1.1 to Kv1.3.";
RL Front. Pharmacol. 11:1010-1010(2020).
CC -!- FUNCTION: Inhibits voltage-gated potassium channel rKv1.1/KCNA1
CC (IC(50)=1.9 nM) (PubMed:25792741, PubMed:32733247). Also shows less
CC potent inhibition on Kv1.2/KCNA2 (IC(50)=105.9 nM), Kv1.3/KCNA3
CC (IC(50)=8.9 nM), and Kv1.6/KCNA6 (IC(50)=63.4 nM) (PubMed:32733247).
CC {ECO:0000269|PubMed:25792741, ECO:0000269|PubMed:32733247}.
CC -!- SUBCELLULAR LOCATION: Secreted {ECO:0000269|PubMed:25792741}.
CC -!- TISSUE SPECIFICITY: Expressed by the venom gland. {ECO:0000305}.
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:Q9NII7}.
CC -!- PTM: C-terminal amidation is not fundamental for activity. It permits a
CC slightly higher activity on Kv1.1/KCNA1 potassium channels (native
CC toxin IC(50)=1.9 nM), than non-amidated recombinant toxin (IC(50)=6.7
CC nM). {ECO:0000269|PubMed:32733247}.
CC -!- MASS SPECTROMETRY: Mass=3962; Method=MALDI;
CC Evidence={ECO:0000269|PubMed:25792741};
CC -!- MISCELLANEOUS: The primary structure of this mature peptide is
CC identical to that of toxin alpha-KTx 3.6 from Mesobuthus martensii (AC
CC Q9NII7). {ECO:0000305}.
CC -!- SIMILARITY: Belongs to the short scorpion toxin superfamily. Potassium
CC channel inhibitor family. Alpha-KTx 03 subfamily.
CC {ECO:0000303|PubMed:25792741}.
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DR AlphaFoldDB; C0HJQ6; -.
DR BMRB; C0HJQ6; -.
DR SMR; C0HJQ6; -.
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.
DR PROSITE; PS01138; SCORP_SHORT_TOXIN; 1.
PE 1: Evidence at protein level;
KW Amidation; Direct protein sequencing; Disulfide bond;
KW Ion channel impairing toxin; Potassium channel impairing toxin; Secreted;
KW Toxin; Voltage-gated potassium channel impairing toxin.
FT CHAIN 1..37
FT /note="Potassium channel toxin alpha-KTx 3.19"
FT /evidence="ECO:0000269|PubMed:25792741"
FT /id="PRO_0000433142"
FT MOD_RES 37
FT /note="Lysine amide"
FT /evidence="ECO:0000269|PubMed:25792741"
FT DISULFID 7..27
FT /evidence="ECO:0000250|UniProtKB:Q9NII7"
FT DISULFID 13..32
FT /evidence="ECO:0000250|UniProtKB:Q9NII7"
FT DISULFID 17..34
FT /evidence="ECO:0000250|UniProtKB:Q9NII7"
FT MUTAGEN 12
FT /note="Q->A: Toxin selectivity change from Kv1.1/KCNA1 to
FT Kv1.3/KCNA3 (no change in ability to inhibit Kv1.3/KCNA3,
FT but important decrease in ability to inhibit Kv1.1/KCNA1,
FT Kv1.2/KCNA2 and Kv1.6/KCNA6 channels); MeKTx13-3_AAAR."
FT /evidence="ECO:0000269|PubMed:32733247"
FT MUTAGEN 15
FT /note="K->A: Toxin selectivity change from Kv1.1/KCNA1 to
FT Kv1.3/KCNA3 (no change in ability to inhibit Kv1.3/KCNA3,
FT but important decrease in ability to inhibit Kv1.1/KCNA1,
FT Kv1.2/KCNA2 and Kv1.6/KCNA6 channels); MeKTx13-3_AAAR."
FT /evidence="ECO:0000269|PubMed:32733247"
FT MUTAGEN 18
FT /note="K->A: Toxin selectivity change from Kv1.1/KCNA1 to
FT Kv1.3/KCNA3 (no change in ability to inhibit Kv1.3/KCNA3,
FT but important decrease in ability to inhibit Kv1.1/KCNA1,
FT Kv1.2/KCNA2 and Kv1.6/KCNA6 channels); MeKTx13-3_AAAR."
FT /evidence="ECO:0000269|PubMed:32733247"
FT MUTAGEN 33
FT /note="D->R: Toxin selectivity change from Kv1.1/KCNA1 to
FT Kv1.3/KCNA3 (no change in ability to inhibit Kv1.3/KCNA3,
FT but important decrease in ability to inhibit Kv1.1/KCNA1,
FT Kv1.2/KCNA2 and Kv1.6/KCNA6 channels); MeKTx13-3_AAAR."
FT /evidence="ECO:0000269|PubMed:32733247"
SQ SEQUENCE 37 AA; 3969 MW; BB95077C7B55D8C8 CRC64;
VGINVKCKHS GQCLKPCKDA GMRFGKCING KCDCTPK
