SCBT_MESMA
ID SCBT_MESMA Reviewed; 83 AA.
AC Q9NBW2; M4HP96;
DT 26-SEP-2003, integrated into UniProtKB/Swiss-Prot.
DT 01-OCT-2000, sequence version 1.
DT 03-AUG-2022, entry version 81.
DE RecName: Full=Toxin BmKBT;
DE Short=BmK BT;
DE AltName: Full=BmKabT;
DE Short=BmK abT;
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], PROTEIN SEQUENCE OF 20-59, FUNCTION, TOXIC
RP DOSE, AND MASS SPECTROMETRY.
RC TISSUE=Venom, and Venom gland;
RX PubMed=10981722; DOI=10.1016/s0014-5793(00)01903-7;
RA Ye J.-G., Wang C.-Y., Li Y.-J., Tan Z.-Y., Yan Y.-P., Li C., Chen J.,
RA Ji Y.-H.;
RT "Purification, cDNA cloning and function assessment of BmK abT, a unique
RT component from the Old World scorpion species.";
RL FEBS Lett. 479:136-140(2000).
RN [2]
RP NUCLEOTIDE SEQUENCE [MRNA].
RX PubMed=10978740; DOI=10.1016/s0041-0101(00)00119-7;
RA Zeng X.-C., Li W.-X., Zhu S.-Y., Peng F., Zhu Z.-H., Liu H., Mao X.;
RT "Molecular cloning and sequence analysis of cDNAs encoding a beta-toxin-
RT like peptide and two MkTx I homologues from scorpion Buthus martensii
RT Karsch.";
RL Toxicon 39:225-232(2001).
RN [3]
RP NUCLEOTIDE SEQUENCE [GENOMIC DNA], BIOASSAY, AND TOXIC DOSE.
RX PubMed=22705625; DOI=10.1016/j.peptides.2012.06.002;
RA Nie Y., Zeng X.C., Luo X., Wu S., Zhang L., Cao H., Zhou J., Zhou L.;
RT "Tremendous intron length differences of the BmKBT and a novel BmKBT-like
RT peptide genes provide a mechanical basis for the rapid or constitutive
RT expression of the peptides.";
RL Peptides 37:150-156(2012).
RN [4]
RP FUNCTION.
RX PubMed=12409001; DOI=10.1016/s0014-2999(02)02363-4;
RA Ji Y.-H., Wang W.-X., Wang Q., Huang Y.-P.;
RT "The binding of BmK abT, a unique neurotoxin, to mammal brain and insect
RT Na(+) channels using biosensor.";
RL Eur. J. Pharmacol. 454:25-30(2002).
CC -!- FUNCTION: This toxin increases the peak sodium current, slows down the
CC inactivation of sodium channels (Nav), and prolongs the action
CC potential of dorsal root ganglion neurons, which indicates that it
CC behaves as a classical alpha-toxin. It binds to mammal brain and insect
CC sodium channels, but with a different manner. This peptide may bind to
CC a distinct receptor site on mammal brain sodium channels, which is
CC unconnected with that for BmKAS (a beta-toxin), BmKIT2 (a beta-toxin)
CC or BmK I (an alpha toxin). In contrast, the receptor site for BmKabT on
CC insect sodium channels might be closely related to that for the beta-
CC insect depressant toxin BmKIT2. Possesses potent toxicity in mice but
CC induces only paralysis in cotton bollworm.
CC {ECO:0000269|PubMed:10981722, ECO:0000269|PubMed:12409001}.
CC -!- SUBCELLULAR LOCATION: Secreted.
CC -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC -!- DOMAIN: Has the structural arrangement of an alpha-helix connected to
CC antiparallel beta-sheets by disulfide bonds (CS-alpha/beta).
CC {ECO:0000305}.
CC -!- MASS SPECTROMETRY: Mass=7212; Method=Electrospray;
CC Evidence={ECO:0000269|PubMed:10981722};
CC -!- TOXIC DOSE: LD(50) is 75 ug/kg by intracerebroventricular injection
CC into mice. {ECO:0000269|PubMed:10981722}.
CC -!- TOXIC DOSE: LD(50) is 150 ug/kg by subcutaneous injection into mice.
CC {ECO:0000269|PubMed:22705625}.
CC -!- SIMILARITY: Belongs to the long (4 C-C) scorpion toxin superfamily.
CC Sodium channel inhibitor family. Beta subfamily. {ECO:0000305}.
CC -!- CAUTION: This toxin is functionally similar to alpha toxins and
CC structurally similar to beta toxins. {ECO:0000305}.
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DR EMBL; AF241269; AAF97048.1; -; mRNA.
DR EMBL; AF513508; AAM49598.1; -; mRNA.
DR EMBL; JN968971; AFR43267.1; -; Genomic_DNA.
DR EMBL; JN968972; AFR43268.1; -; Genomic_DNA.
DR AlphaFoldDB; Q9NBW2; -.
DR SMR; Q9NBW2; -.
DR GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR GO; GO:0019871; F:sodium channel inhibitor activity; IEA:InterPro.
DR GO; GO:0090729; F:toxin activity; IEA:UniProtKB-KW.
DR GO; GO:0006952; P:defense response; IEA:InterPro.
DR CDD; cd00107; Knot1; 1.
DR Gene3D; 3.30.30.10; -; 1.
DR InterPro; IPR044062; LCN-type_CS_alpha_beta_dom.
DR InterPro; IPR003614; Scorpion_toxin-like.
DR InterPro; IPR036574; Scorpion_toxin-like_sf.
DR InterPro; IPR018218; Scorpion_toxinL.
DR InterPro; IPR002061; Scorpion_toxinL/defensin.
DR Pfam; PF00537; Toxin_3; 1.
DR PRINTS; PR00285; SCORPNTOXIN.
DR SUPFAM; SSF57095; SSF57095; 1.
DR PROSITE; PS51863; LCN_CSAB; 1.
PE 1: Evidence at protein level;
KW Direct protein sequencing; Disulfide bond; Ion channel impairing toxin;
KW Neurotoxin; Secreted; Signal; Toxin;
KW Voltage-gated sodium channel impairing toxin.
FT SIGNAL 1..19
FT /evidence="ECO:0000269|PubMed:10981722"
FT CHAIN 20..82
FT /note="Toxin BmKBT"
FT /id="PRO_0000035257"
FT PROPEP 83
FT /note="Removed by a carboxypeptidase"
FT /evidence="ECO:0000305"
FT /id="PRO_0000035258"
FT DOMAIN 21..81
FT /note="LCN-type CS-alpha/beta"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU01210"
FT DISULFID 31..80
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU01210"
FT DISULFID 35..54
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU01210"
FT DISULFID 41..61
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU01210"
FT DISULFID 45..63
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU01210"
SQ SEQUENCE 83 AA; 9378 MW; FAB77A550F2F1F1C CRC64;
MKAALLLVIF SLMLIGVLTK KSGYPTDHEG CKNWCVLNHS CGILCEGYGG SGYCYFWKLA
CWCDDIHNWV PTWSRATNKC RAK
