KAX21_CENNO
ID KAX21_CENNO Reviewed; 39 AA.
AC P08815;
DT 01-NOV-1988, integrated into UniProtKB/Swiss-Prot.
DT 19-JUL-2004, sequence version 3.
DT 25-MAY-2022, entry version 111.
DE RecName: Full=Potassium channel toxin alpha-KTx 2.1 {ECO:0000305};
DE AltName: Full=Noxiustoxin {ECO:0000303|PubMed:2448164, ECO:0000303|Ref.1};
DE Short=NTx {ECO:0000303|PubMed:2448164};
DE AltName: Full=Toxin II.11;
OS Centruroides noxius (Mexican scorpion).
OC Eukaryota; Metazoa; Ecdysozoa; Arthropoda; Chelicerata; Arachnida;
OC Scorpiones; Buthida; Buthoidea; Buthidae; Centruroides.
OX NCBI_TaxID=6878;
RN [1]
RP PROTEIN SEQUENCE, AND SUBCELLULAR LOCATION.
RC TISSUE=Venom;
RA Possani L.D., Martin B.M., Svendsen I.;
RT "The primary structure of noxiustoxin. A K channel blocking peptide,
RT purified from the venom of the scorpion Centruroides noxius Hoffmann.";
RL Carlsberg Res. Commun. 47:285-289(1982).
RN [2]
RP FUNCTION.
RX PubMed=2448164; DOI=10.1016/0014-5793(88)81439-x;
RA Valdivia H.H., Smith J.S., Martin B.M., Coronado R., Possani L.D.;
RT "Charybdotoxin and noxiustoxin, two homologous peptide inhibitors of the K+
RT (Ca2+) channel.";
RL FEBS Lett. 226:280-284(1988).
RN [3]
RP SYNTHESIS OF 1-9 AND 30-39.
RX PubMed=2746197; DOI=10.1007/bf01255815;
RA Gurrola G.B., Molinar-Rode R., Sitges M., Bayon A., Possani L.D.;
RT "Synthetic peptides corresponding to the sequence of noxiustoxin indicate
RT that the active site of this K+ channel blocker is located on its amino-
RT terminal portion.";
RL J. Neural Transm. 77:11-20(1989).
RN [4]
RP SYNTHESIS, AND AMIDATION AT ASN-39.
RA Nutt R.F., Arison B.H., Smith J.S.;
RT "Structure revision of the scorpion toxin noxiustoxin through total
RT chemical synthesis.";
RL (In) Schneider C.H., Eberles A.N. (eds.);
RL Peptides 1992, pp.101-102, Escom Science Publishers, Leiden (1993).
RN [5]
RP FUNCTION.
RX PubMed=7517498;
RA Grissmer S., Nguyen A.N., Aiyar J., Hanson D.C., Mather R.J., Gutman G.A.,
RA Karmilowicz M.J., Auperin D.D., Chandy K.G.;
RT "Pharmacological characterization of five cloned voltage-gated K+ channels,
RT types Kv1.1, 1.2, 1.3, 1.5, and 3.1, stably expressed in mammalian cell
RT lines.";
RL Mol. Pharmacol. 45:1227-1234(1994).
RN [6]
RP STRUCTURE BY NMR, AND DISULFIDE BONDS.
RX PubMed=8527429; DOI=10.1021/bi00051a004;
RA Dauplais M., Gilquin B., Possani L.D., Gurrola-Briones G., Roumestand C.,
RA Menez A.;
RT "Determination of the three-dimensional solution structure of noxiustoxin:
RT analysis of structural differences with related short-chain scorpion
RT toxins.";
RL Biochemistry 34:16563-16573(1995).
CC -!- FUNCTION: Blocks voltage-gated potassium channels (mKv1.1/KCNA1 (Kd>25
CC nM), rKv1.2/KCNA2 (Kd=2 nM), mKv1.3/KCNA3 (Kd=1 nM), hKv1.5/KCNA5
CC (Kd>25 nM) and mKv3.1/KCNC1 (Kd>25 nM)) and calcium-activated potassium
CC channels (KCa1.1/KCNMA1 and KCa3.1/KCNN4, Kd>25 nM).
CC {ECO:0000269|PubMed:2448164, ECO:0000269|PubMed:7517498}.
CC -!- SUBCELLULAR LOCATION: Secreted {ECO:0000269|Ref.1}.
CC -!- TISSUE SPECIFICITY: Expressed by the venom gland. {ECO:0000305|Ref.1}.
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:8527429}.
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; 1SXM; NMR; -; A=1-39.
DR PDBsum; 1SXM; -.
DR AlphaFoldDB; P08815; -.
DR SMR; P08815; -.
DR EvolutionaryTrace; P08815; -.
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; Amidation;
KW Calcium-activated potassium channel impairing toxin;
KW Direct protein sequencing; Disulfide bond; Ion channel impairing toxin;
KW Neurotoxin; Potassium channel impairing toxin; Secreted; Toxin;
KW Voltage-gated potassium channel impairing toxin.
FT PEPTIDE 1..39
FT /note="Potassium channel toxin alpha-KTx 2.1"
FT /evidence="ECO:0000269|Ref.1"
FT /id="PRO_0000044905"
FT REGION 26..34
FT /note="Interaction with Ca(2+)-activated K(+) channels"
FT /evidence="ECO:0000255"
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 MOD_RES 39
FT /note="Asparagine amide"
FT /evidence="ECO:0000269|Ref.4"
FT DISULFID 7..29
FT /evidence="ECO:0000269|PubMed:8527429,
FT ECO:0000312|PDB:1SXM"
FT DISULFID 13..34
FT /evidence="ECO:0000269|PubMed:8527429,
FT ECO:0000312|PDB:1SXM"
FT DISULFID 17..36
FT /evidence="ECO:0000269|PubMed:8527429,
FT ECO:0000312|PDB:1SXM"
FT TURN 14..16
FT /evidence="ECO:0007829|PDB:1SXM"
FT HELIX 17..20
FT /evidence="ECO:0007829|PDB:1SXM"
FT STRAND 27..30
FT /evidence="ECO:0007829|PDB:1SXM"
FT STRAND 33..36
FT /evidence="ECO:0007829|PDB:1SXM"
SQ SEQUENCE 39 AA; 4202 MW; 131DC4A78D497E0D CRC64;
TIINVKCTSP KQCSKPCKEL YGSSAGAKCM NGKCKCYNN
