KAX25_CENLM
ID KAX25_CENLM Reviewed; 39 AA.
AC P59847;
DT 19-SEP-2003, integrated into UniProtKB/Swiss-Prot.
DT 19-SEP-2003, sequence version 1.
DT 25-MAY-2022, entry version 80.
DE RecName: Full=Potassium channel toxin alpha-KTx 2.5;
DE AltName: Full=Hongotoxin-1 {ECO:0000303|PubMed:9446567};
DE Short=HgTX1 {ECO:0000303|PubMed:9446567};
OS Centruroides limbatus (Bark scorpion).
OC Eukaryota; Metazoa; Ecdysozoa; Arthropoda; Chelicerata; Arachnida;
OC Scorpiones; Buthida; Buthoidea; Buthidae; Centruroides.
OX NCBI_TaxID=244936;
RN [1]
RP PROTEIN SEQUENCE, FUNCTION, ACTIVITY PROFILE, MUTAGENESIS OF ALA-19 AND
RP TYR-37, AND SUBCELLULAR LOCATION.
RC TISSUE=Venom;
RX PubMed=9446567; DOI=10.1074/jbc.273.5.2639;
RA Koschak A., Bugianesi R.M., Mitterdorfer J., Kaczorowski G.J., Garcia M.L.,
RA Knaus H.-G.;
RT "Subunit composition of brain voltage-gated potassium channels determined
RT by hongotoxin-1, a novel peptide derived from Centruroides limbatus
RT venom.";
RL J. Biol. Chem. 273:2639-2644(1998).
RN [2]
RP FUNCTION, AND RECOMBINANT EXPRESSION.
RX PubMed=31276191; DOI=10.1002/1873-3468.13530;
RA Kasheverov I.E., Oparin P.B., Zhmak M.N., Egorova N.S., Ivanov I.A.,
RA Gigolaev A.M., Nekrasova O.V., Serebryakova M.V., Kudryavtsev D.S.,
RA Prokopev N.A., Hoang A.N., Tsetlin V.I., Vassilevski A.A., Utkin Y.N.;
RT "Scorpion toxins interact with nicotinic acetylcholine receptors.";
RL FEBS Lett. 593:2779-2789(2019).
RN [3]
RP STRUCTURE BY NMR, DISULFIDE BONDS, MASS SPECTROMETRY, AND MUTAGENESIS OF
RP ALA-19 AND TYR-37.
RC TISSUE=Venom;
RX PubMed=12009929; DOI=10.1021/bc015543s;
RA Pragl B., Koschak A., Trieb M., Obermair G., Kaufmann W.A., Gerster U.,
RA Blanc E., Hahn C., Prinz H., Schuetz G., Darbon H., Gruber H.J.,
RA Knaus H.-G.;
RT "Synthesis, characterization, and application of cy-dye- and alexa-dye-
RT labeled hongotoxin(1) analogues. The first high affinity fluorescence
RT probes for voltage-gated K+ channels.";
RL Bioconj. Chem. 13:416-425(2002).
CC -!- FUNCTION: Potent selective inhibitor of Kv1.1/KCNA1, Kv1.2/KCNA2,
CC Kv1.3/KCNA3 voltage-gated potassium channels (PubMed:9446567). Weak
CC inhibitor of Kv1.6/KCNA6 potassium channel (PubMed:9446567). It also
CC shows a weak interaction with nicotinic acetylcholine receptors
CC (nAChR), suggesting it may weakly inhibit it (PubMed:31276191).
CC {ECO:0000269|PubMed:9446567}.
CC -!- SUBCELLULAR LOCATION: Secreted {ECO:0000269|PubMed:9446567}.
CC -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC {ECO:0000305|PubMed:9446567}.
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:12009929}.
CC -!- MASS SPECTROMETRY: Mass=4219; Method=Electrospray;
CC Evidence={ECO:0000269|PubMed:12009929};
CC -!- MISCELLANEOUS: Does not block Kv1.4/KCNA4 and Kv1.5/KCNA5 currents.
CC {ECO:0000269|PubMed:9446567}.
CC -!- SIMILARITY: Belongs to the short scorpion toxin superfamily. Potassium
CC channel inhibitor family. Alpha-KTx 02 subfamily. {ECO:0000305}.
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DR PDB; 1HLY; NMR; -; A=1-39.
DR PDBsum; 1HLY; -.
DR AlphaFoldDB; P59847; -.
DR SMR; P59847; -.
DR EvolutionaryTrace; P59847; -.
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; Direct protein sequencing; Disulfide bond;
KW Ion channel impairing toxin; Neurotoxin; Potassium channel impairing toxin;
KW Secreted; Toxin; Voltage-gated potassium channel impairing toxin.
FT PEPTIDE 1..39
FT /note="Potassium channel toxin alpha-KTx 2.5"
FT /evidence="ECO:0000269|PubMed:9446567"
FT /id="PRO_0000044903"
FT SITE 28
FT /note="Basic residue of the functional dyad"
FT /evidence="ECO:0000250"
FT SITE 37
FT /note="Aromatic residue of the functional dyad"
FT /evidence="ECO:0000250"
FT DISULFID 7..29
FT /evidence="ECO:0000269|PubMed:12009929"
FT DISULFID 13..34
FT /evidence="ECO:0000269|PubMed:12009929"
FT DISULFID 17..36
FT /evidence="ECO:0000269|PubMed:12009929"
FT MUTAGEN 19
FT /note="A->C: No loss of activity."
FT /evidence="ECO:0000269|PubMed:12009929"
FT MUTAGEN 19
FT /note="A->Y: No loss of activity; when associated with F-
FT 37."
FT /evidence="ECO:0000269|PubMed:12009929"
FT MUTAGEN 37
FT /note="Y->F: No loss of activity; when associated with Y-
FT 19."
FT /evidence="ECO:0000269|PubMed:12009929"
FT STRAND 8..10
FT /evidence="ECO:0007829|PDB:1HLY"
FT HELIX 11..13
FT /evidence="ECO:0007829|PDB:1HLY"
FT HELIX 14..20
FT /evidence="ECO:0007829|PDB:1HLY"
FT STRAND 26..30
FT /evidence="ECO:0007829|PDB:1HLY"
FT STRAND 33..37
FT /evidence="ECO:0007829|PDB:1HLY"
SQ SEQUENCE 39 AA; 4226 MW; B4ABC83F8EE7E637 CRC64;
TVIDVKCTSP KQCLPPCKAQ FGIRAGAKCM NGKCKCYPH
