KAX12_LEIHE
ID KAX12_LEIHE Reviewed; 59 AA.
AC P45628;
DT 01-NOV-1995, integrated into UniProtKB/Swiss-Prot.
DT 21-NOV-2003, sequence version 2.
DT 25-MAY-2022, entry version 110.
DE RecName: Full=Potassium channel toxin alpha-KTx 1.2;
DE AltName: Full=ChTX-Lq2 {ECO:0000303|PubMed:2477548};
DE AltName: Full=ChTx-d;
DE AltName: Full=Charybdotoxin-2 {ECO:0000303|PubMed:7533951};
DE Short=ChTx-2;
DE AltName: Full=Lqh 18-2;
DE AltName: Full=Toxin 18-2 {ECO:0000303|PubMed:7533951};
DE Flags: Precursor;
OS Leiurus hebraeus (Deathstalker scorpion) (Leiurus quinquestriatus
OS hebraeus).
OC Eukaryota; Metazoa; Ecdysozoa; Arthropoda; Chelicerata; Arachnida;
OC Scorpiones; Buthida; Buthoidea; Buthidae; Leiurus.
OX NCBI_TaxID=6884;
RN [1]
RP NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RC TISSUE=Single abdominal segment;
RX PubMed=9929387; DOI=10.1007/pl00006457;
RA Froy O., Sagiv T., Poreh M., Urbach D., Zilberberg N., Gurevitz M.;
RT "Dynamic diversification from a putative common ancestor of scorpion toxins
RT affecting sodium, potassium, and chloride channels.";
RL J. Mol. Evol. 48:187-196(1999).
RN [2]
RP PROTEIN SEQUENCE OF 23-59, FUNCTION, SUBCELLULAR LOCATION, AND
RP PYROGLUTAMATE FORMATION AT GLN-23.
RC TISSUE=Venom;
RX PubMed=2477548; DOI=10.1007/bf01870284;
RA Lucchesi K., Ravindran A., Young H., Moczydlowski E.;
RT "Analysis of the blocking activity of charybdotoxin homologs and iodinated
RT derivatives against Ca2+-activated K+ channels.";
RL J. Membr. Biol. 109:269-281(1989).
RN [3]
RP PROTEIN SEQUENCE OF 28-59, AND FUNCTION.
RC TISSUE=Venom;
RX PubMed=7533951; DOI=10.1016/0041-0101(94)90415-4;
RA Marshall D.L., Vatanpour H., Harvey A.L., Boyot P., Pinkasfeld S.,
RA Doljansky Y., Bouet F., Menez A.;
RT "Neuromuscular effects of some potassium channel blocking toxins from the
RT venom of the scorpion Leiurus quinquestriatus hebreus.";
RL Toxicon 32:1433-1443(1994).
RN [4]
RP STRUCTURE BY NMR, AND DISULFIDE BONDS.
RX PubMed=10081954;
RX DOI=10.1002/(sici)1097-0134(19990301)34:4<417::aid-prot1>3.0.co;2-r;
RA Renisio J.-G., Lu Z., Blanc E., Jin W., Lewis J.H., Bornet O., Darbon H.;
RT "Solution structure of potassium channel-inhibiting scorpion toxin Lq2.";
RL Proteins 34:417-426(1999).
CC -!- FUNCTION: Blocks calcium-activated potassium channels (Kd=43 nM on
CC KCa1.1/KCNMA1). Has a potent presynaptic facilitatory action, with less
CC effect on direct muscle stimulation. {ECO:0000269|PubMed:2477548,
CC ECO:0000269|PubMed:7533951}.
CC -!- SUBCELLULAR LOCATION: Secreted {ECO:0000269|PubMed:2477548}.
CC -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC {ECO:0000305|PubMed:2477548}.
CC -!- DOMAIN: Has the structural arrangement of an alpha-helix connected to a
CC beta-sheet by disulfide bonds (CSalpha/beta).
CC {ECO:0000269|PubMed:10081954}.
CC -!- SIMILARITY: Belongs to the short scorpion toxin superfamily. Potassium
CC channel inhibitor family. Alpha-KTx 01 subfamily. {ECO:0000305}.
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DR PIR; B60963; B60963.
DR PDB; 1LIR; NMR; -; A=24-59.
DR PDBsum; 1LIR; -.
DR AlphaFoldDB; P45628; -.
DR SMR; P45628; -.
DR EvolutionaryTrace; P45628; -.
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 3D-structure; Calcium-activated potassium channel impairing toxin;
KW Direct protein sequencing; Disulfide bond; Ion channel impairing toxin;
KW Neurotoxin; Potassium channel impairing toxin; Pyrrolidone carboxylic acid;
KW Secreted; Signal; Toxin.
FT SIGNAL 1..22
FT /evidence="ECO:0000269|PubMed:2477548"
FT CHAIN 23..59
FT /note="Potassium channel toxin alpha-KTx 1.2"
FT /evidence="ECO:0000269|PubMed:2477548"
FT /id="PRO_0000035309"
FT REGION 48..55
FT /note="Interaction with Ca(2+)-activated K(+) channels"
FT /evidence="ECO:0000255"
FT SITE 49
FT /note="Basic residue of the functional dyad"
FT /evidence="ECO:0000250"
FT SITE 58
FT /note="Aromatic residue of the functional dyad"
FT /evidence="ECO:0000250"
FT MOD_RES 23
FT /note="Pyrrolidone carboxylic acid"
FT /evidence="ECO:0000269|PubMed:2477548"
FT DISULFID 29..50
FT /evidence="ECO:0000269|PubMed:10081954,
FT ECO:0000312|PDB:1LIR"
FT DISULFID 35..55
FT /evidence="ECO:0000269|PubMed:10081954,
FT ECO:0000312|PDB:1LIR"
FT DISULFID 39..57
FT /evidence="ECO:0000269|PubMed:10081954,
FT ECO:0000312|PDB:1LIR"
FT HELIX 32..43
FT /evidence="ECO:0007829|PDB:1LIR"
FT STRAND 48..51
FT /evidence="ECO:0007829|PDB:1LIR"
FT STRAND 54..57
FT /evidence="ECO:0007829|PDB:1LIR"
SQ SEQUENCE 59 AA; 6772 MW; C1DBB5F32A19E3C8 CRC64;
MKILSVLLLA LIICSIIDWS EGQFTQESCT ASNQCWSICK RLHNTNRGKC MNKKCRCYS
