KBX2_MESMA
ID KBX2_MESMA Reviewed; 90 AA.
AC Q9NJC6; Q8WS33; Q95P93;
DT 04-JAN-2005, integrated into UniProtKB/Swiss-Prot.
DT 01-OCT-2000, sequence version 1.
DT 25-MAY-2022, entry version 51.
DE RecName: Full=Potassium channel toxin BmTXK-beta;
DE AltName: Full=BmKLK;
DE AltName: Full=Potassium channel toxin beta-KTx 3;
DE AltName: Full=Toxin BmTX K-beta;
DE Short=BmTXKbeta;
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 [MRNA].
RC TISSUE=Venom gland;
RX PubMed=10471839; DOI=10.1016/s0014-5793(99)01101-1;
RA Zhu S.-Y., Li W.-X., Zeng X.-C., Jiang D.-H., Mao X., Liu H.;
RT "Molecular cloning and sequencing of two 'short chain' and two 'long chain'
RT K(+) channel-blocking peptides from the Chinese scorpion Buthus martensii
RT Karsch.";
RL FEBS Lett. 457:509-514(1999).
RN [2]
RP NUCLEOTIDE SEQUENCE [GENOMIC DNA] OF 30-90.
RX PubMed=11718723; DOI=10.1016/s0014-5793(01)03067-8;
RA Zhu S.-Y., Li W.-X., Cao Z.;
RT "A naturally occurring non-coding fusion transcript derived from scorpion
RT venom gland: implication for the regulation of scorpion toxin gene
RT expression.";
RL FEBS Lett. 508:241-244(2001).
RN [3]
RP NUCLEOTIDE SEQUENCE [MRNA] OF 1-28.
RC TISSUE=Venom gland;
RX PubMed=12044895; DOI=10.1016/s0014-5793(02)02812-0;
RA Zeng X.-C., Wang S.-X.;
RT "Evidence that BmTXK beta-BmKCT cDNA from Chinese scorpion Buthus martensii
RT Karsch is an artifact generated in the reverse transcription process.";
RL FEBS Lett. 520:183-184(2002).
RN [4]
RP FUNCTION.
RX PubMed=12668201; DOI=10.1016/s0196-9781(03)00025-1;
RA Cao Z., Xiao F., Peng F., Jiang D., Mao X., Liu H., Li W., Hu D., Wang T.;
RT "Expression, purification and functional characterization of a recombinant
RT scorpion venom peptide BmTXKbeta.";
RL Peptides 24:187-192(2003).
CC -!- FUNCTION: This recombinant peptide reversibly and dose-dependently
CC inhibits the transient outward potassium current (I(To)) of rabbit
CC atrial myocyte and prolongs the action potential duration of rabbit
CC atrial myocyte without affecting the action potential amplitude. Thus,
CC the voltage-gated potassium channels Kv4.1/KCND1, Kv4.2/KCND2,
CC Kv4.3/KCND3 may be the target of this toxin.
CC {ECO:0000269|PubMed:12668201}.
CC -!- SUBCELLULAR LOCATION: Secreted {ECO:0000250}.
CC -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC -!- SIMILARITY: Belongs to the long chain scorpion toxin family. Class 2
CC subfamily. {ECO:0000305}.
CC -!- CAUTION: It is uncertain whether Met-1 or Met-2 is the initiator.
CC {ECO:0000305}.
CC ---------------------------------------------------------------------------
CC Copyrighted by the UniProt Consortium, see https://www.uniprot.org/terms
CC Distributed under the Creative Commons Attribution (CC BY 4.0) License
CC ---------------------------------------------------------------------------
DR EMBL; AF155371; AAF31480.1; -; mRNA.
DR EMBL; AF153691; AAP33618.1; -; mRNA.
DR EMBL; AF380939; AAL58197.1; -; Genomic_DNA.
DR EMBL; AF155365; AAK61815.1; -; mRNA.
DR EMBL; AY055475; AAL24435.1; -; mRNA.
DR AlphaFoldDB; Q9NJC6; -.
DR SMR; Q9NJC6; -.
DR TCDB; 1.C.47.3.2; the insect/fungal defensin (insect/fungal defensin) family.
DR GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR GO; GO:0015459; F:potassium channel regulator activity; IEA:UniProtKB-KW.
DR GO; GO:0090729; F:toxin activity; IEA:UniProtKB-KW.
DR InterPro; IPR029237; Long_scorpion_toxin.
DR Pfam; PF14866; Toxin_38; 1.
DR PROSITE; PS51862; BSPN_CSAB; 1.
PE 2: Evidence at transcript level;
KW Disulfide bond; Ion channel impairing toxin; Neurotoxin;
KW Potassium channel impairing toxin; Secreted; Signal; Toxin;
KW Voltage-gated potassium channel impairing toxin.
FT SIGNAL 1..22
FT /evidence="ECO:0000255"
FT PROPEP 23..29
FT /evidence="ECO:0000305"
FT /id="PRO_0000035344"
FT CHAIN 30..90
FT /note="Potassium channel toxin BmTXK-beta"
FT /id="PRO_0000035345"
FT DOMAIN 55..90
FT /note="BetaSPN-type CS-alpha/beta"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU01209"
FT DISULFID 58..78
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU01209"
FT DISULFID 65..83
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU01209"
FT DISULFID 69..85
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU01209"
FT CONFLICT 28
FT /note="I -> M (in Ref. 3; AAL24435)"
FT /evidence="ECO:0000305"
SQ SEQUENCE 90 AA; 10431 MW; FE949802055941A4 CRC64;
MMKQQFFLFL AVIVMISSVI EAGRGKEIMK NIKEKLTEVK DKMKHSWNKL TSMSEYACPV
IEKWCEDHCA AKKAIGKCED TECKCLKLRK
