ID   SIXB_MESMA              Reviewed;          85 AA.
AC   Q95WX6;
DT   07-DEC-2004, integrated into UniProtKB/Swiss-Prot.
DT   01-DEC-2001, sequence version 1.
DT   03-AUG-2022, entry version 73.
DE   RecName: Full=Beta-insect depressant toxin BmKITb {ECO:0000303|PubMed:12472844};
DE            Short=BmK ITb {ECO:0000303|PubMed:12472844};
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], PROTEIN SEQUENCE OF 22-56, AMIDATION AT
RP   GLY-82, ELECTROPHYSIOLOGICAL CHARACTERIZATION, MASS SPECTROMETRY, AND
RP   SUBCELLULAR LOCATION.
RC   TISSUE=Venom, and Venom gland;
RX   PubMed=12472844; DOI=10.1034/j.1399-3011.2003.21020.x;
RA   Wang C.-G., Ling M.-H., Chi C.-W., Wang D.-C., Pelhate M.;
RT   "Purification of two depressant insect neurotoxins and their gene cloning
RT   from the scorpion Buthus martensi Karsch.";
RL   J. Pept. Res. 61:7-16(2003).
CC   -!- FUNCTION: Depressant insect beta-toxins cause a transient contraction
CC       paralysis followed by a slow flaccid paralysis. They bind voltage-
CC       independently at site-4 of sodium channels (Nav) and shift the voltage
CC       of activation toward more negative potentials thereby affecting sodium
CC       channel activation and promoting spontaneous and repetitive firing.
CC       However, this toxin has some characteristics of excitatory toxins such
CC       as bursts of activity after the membrane has been hyperpolarized. This
CC       toxin is active only on insects.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000269|PubMed:12472844}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC       {ECO:0000305|PubMed:12472844}.
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=6763.9; Method=Electrospray;
CC       Evidence={ECO:0000269|PubMed:12472844};
CC   -!- SIMILARITY: Belongs to the long (4 C-C) scorpion toxin superfamily.
CC       Sodium channel inhibitor family. Beta subfamily. {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; AF272777; AAF77063.2; -; Genomic_DNA.
DR   AlphaFoldDB; Q95WX6; -.
DR   SMR; Q95WX6; -.
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   SMART; SM00505; Knot1; 1.
DR   SUPFAM; SSF57095; SSF57095; 1.
DR   PROSITE; PS51863; LCN_CSAB; 1.
PE   1: Evidence at protein level;
KW   Amidation; Direct protein sequencing; Disulfide bond;
KW   Ion channel impairing toxin; Neurotoxin; Secreted; Signal; Toxin;
KW   Voltage-gated sodium channel impairing toxin.
FT   SIGNAL          1..21
FT                   /evidence="ECO:0000269|PubMed:12472844"
FT   CHAIN           22..82
FT                   /note="Beta-insect depressant toxin BmKITb"
FT                   /evidence="ECO:0000305|PubMed:12472844"
FT                   /id="PRO_0000035206"
FT   DOMAIN          22..82
FT                   /note="LCN-type CS-alpha/beta"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01210"
FT   MOD_RES         82
FT                   /note="Glycine amide"
FT                   /evidence="ECO:0000269|PubMed:12472844"
FT   DISULFID        31..81
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01210"
FT   DISULFID        35..56
FT                   /evidence="ECO:0000250|UniProtKB:P56637,
FT                   ECO:0000255|PROSITE-ProRule:PRU01210"
FT   DISULFID        42..63
FT                   /evidence="ECO:0000250|UniProtKB:P56637,
FT                   ECO:0000255|PROSITE-ProRule:PRU01210"
FT   DISULFID        46..65
FT                   /evidence="ECO:0000250|UniProtKB:P56637,
FT                   ECO:0000255|PROSITE-ProRule:PRU01210"
FT   CONFLICT        33
FT                   /note="V -> I (in Ref. 1; fig.5)"
FT                   /evidence="ECO:0000305"
FT   CONFLICT        48
FT                   /note="A -> G (in Ref. 1; fig.5)"
FT                   /evidence="ECO:0000305"
SQ   SEQUENCE   85 AA;  9330 MW;  80CDD3914956DE8C CRC64;
     MKLFLLLVIS ASMLIDGLVN ADGYIRGSNG CKVSCLWGNE GCNKECKAFG AYYGYCWTWG
     LACWCQGLPD DKTWKSESNT CGGKK