KAX16_MESMA
ID KAX16_MESMA Reviewed; 58 AA.
AC Q9NII5; P58489;
DT 23-JAN-2002, integrated into UniProtKB/Swiss-Prot.
DT 01-OCT-2000, sequence version 1.
DT 25-MAY-2022, entry version 93.
DE RecName: Full=Potassium channel toxin alpha-KTx 1.6;
DE AltName: Full=BmTX2 {ECO:0000303|PubMed:9354615};
DE AltName: Full=Neurotoxin TX2;
DE Flags: Precursor;
OS Mesobuthus martensii (Manchurian scorpion) (Buthus martensii).
OC Eukaryota; Metazoa; Ecdysozoa; Arthropoda; Chelicerata; Arachnida;
OC Scorpiones; Buthida; Buthoidea; Buthidae; Mesobuthus.
OX NCBI_TaxID=34649;
RN [1]
RP NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX PubMed=10698710; DOI=10.1042/bj3460805;
RA Dai L., Wu J.-J., Gu Y.-H., Lan Z.-D., Ling M.-H., Chi C.-W.;
RT "Genomic organization of three novel toxins from the scorpion Buthus
RT martensi Karsch that are active on potassium channels.";
RL Biochem. J. 346:805-809(2000).
RN [2]
RP NUCLEOTIDE SEQUENCE [GENOMIC DNA / MRNA].
RX PubMed=10978761; DOI=10.1016/s0041-0101(00)00130-6;
RA Zeng X.-C., Zhu Z.-H., Li W.-X., Zhu S.-Y., Peng F., Mao X., Liu H.;
RT "Molecular cloning and genomic organization of a K(+) channel toxin from
RT the Chinese scorpion Buthus martensii Karsch.";
RL Toxicon 39:407-410(2001).
RN [3]
RP PROTEIN SEQUENCE OF 22-58, SYNTHESIS OF 22-58, FUNCTION, SUBCELLULAR
RP LOCATION, PYROGLUTAMATE FORMATION AT GLN-22, AND ACTIVITY PROFILE.
RC TISSUE=Venom;
RX PubMed=9354615; DOI=10.1021/bi971044w;
RA Romi-Lebrun R., Lebrun B., Martin-Eauclaire M.-F., Ishiguro M.,
RA Escoubas P., Wu F.Q., Hisada M., Pongs O., Nakajima T.;
RT "Purification, characterization, and synthesis of three novel toxins from
RT the Chinese scorpion Buthus martensi, which act on K+ channels.";
RL Biochemistry 36:13473-13482(1997).
RN [4]
RP FUNCTION, AND ACTIVITY PROFILE.
RX PubMed=18687312; DOI=10.1016/j.bcp.2008.07.008;
RA Abdel-Mottaleb Y., Corzo G., Martin-Eauclaire M.F., Satake H., Ceard B.,
RA Peigneur S., Nambaru P., Bougis P.E., Possani L.D., Tytgat J.;
RT "A common 'hot spot' confers hERG blockade activity to alpha-scorpion
RT toxins affecting K+ channels.";
RL Biochem. Pharmacol. 76:805-815(2008).
RN [5]
RP STRUCTURE BY NMR OF 23-58, DISULFIDE BONDS, AND SYNTHESIS OF 23-58.
RX PubMed=9730813; DOI=10.1021/bi9809371;
RA Blanc E., Romi-Lebrun R., Bornet O., Nakajima T., Darbon H.;
RT "Solution structure of two new toxins from the venom of the Chinese
RT scorpion Buthus martensi Karsch blockers of potassium channels.";
RL Biochemistry 37:12412-12418(1998).
CC -!- FUNCTION: Potent blocker of both large-conductance calcium-activated
CC potassium channels (KCa1.1/KCNMA1) and voltage-gated potassium channels
CC (Kv1.3/KCNA3 and ERG1/Kv11.1/KCNH2). {ECO:0000269|PubMed:18687312,
CC ECO:0000269|PubMed:9354615}.
CC -!- SUBCELLULAR LOCATION: Secreted {ECO:0000269|PubMed:9354615}.
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 -!- SIMILARITY: Belongs to the short scorpion toxin superfamily. Potassium
CC channel inhibitor family. Alpha-KTx 01 subfamily. {ECO:0000305}.
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DR EMBL; AF208300; AAF63972.1; -; Genomic_DNA.
DR EMBL; AF151537; AAQ13576.1; -; mRNA.
DR EMBL; AF247058; AAK73518.1; -; Genomic_DNA.
DR PDB; 2BMT; NMR; -; A=23-58.
DR PDBsum; 2BMT; -.
DR AlphaFoldDB; Q9NII5; -.
DR BMRB; Q9NII5; -.
DR SMR; Q9NII5; -.
DR EvolutionaryTrace; Q9NII5; -.
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; Voltage-gated potassium channel impairing toxin.
FT SIGNAL 1..21
FT /evidence="ECO:0000269|PubMed:9354615"
FT CHAIN 22..58
FT /note="Potassium channel toxin alpha-KTx 1.6"
FT /evidence="ECO:0000269|PubMed:9354615"
FT /id="PRO_0000035318"
FT SITE 48
FT /note="Basic residue of the functional dyad"
FT /evidence="ECO:0000250"
FT SITE 57
FT /note="Aromatic residue of the functional dyad"
FT /evidence="ECO:0000250"
FT MOD_RES 22
FT /note="Pyrrolidone carboxylic acid"
FT /evidence="ECO:0000269|PubMed:9354615"
FT DISULFID 28..49
FT /evidence="ECO:0000269|PubMed:9730813,
FT ECO:0000312|PDB:2BMT"
FT DISULFID 34..54
FT /evidence="ECO:0000269|PubMed:9730813,
FT ECO:0000312|PDB:2BMT"
FT DISULFID 38..56
FT /evidence="ECO:0000269|PubMed:9730813,
FT ECO:0000312|PDB:2BMT"
FT STRAND 23..27
FT /evidence="ECO:0007829|PDB:2BMT"
FT HELIX 32..34
FT /evidence="ECO:0007829|PDB:2BMT"
FT HELIX 35..41
FT /evidence="ECO:0007829|PDB:2BMT"
FT STRAND 47..50
FT /evidence="ECO:0007829|PDB:2BMT"
FT STRAND 53..56
FT /evidence="ECO:0007829|PDB:2BMT"
SQ SEQUENCE 58 AA; 6507 MW; F19AA7351B9708B8 CRC64;
MKISFLLLLA IVICSIGWTE AQFTNVSCSA SSQCWPVCKK LFGTYRGKCM NSKCRCYS
