ID   CTXLB_MESMA             Reviewed;          59 AA.
AC   Q9BJW4;
DT   28-FEB-2003, integrated into UniProtKB/Swiss-Prot.
DT   01-JUN-2001, sequence version 1.
DT   03-AUG-2022, entry version 60.
DE   RecName: Full=Chlorotoxin-like peptide Bm12-b {ECO:0000303|PubMed:22887697};
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].
RA   Xu C.-Q., Chi C.-W.;
RT   "A novel neurotoxin from scorpion BmK.";
RL   Submitted (DEC-2000) to the EMBL/GenBank/DDBJ databases.
RN   [2]
RP   MASS SPECTROMETRY, AND SUBCELLULAR LOCATION.
RC   TISSUE=Venom;
RX   PubMed=22887697; DOI=10.1002/pmic.201200224;
RA   Xu J., Zhang X., Guo Z., Yan J., Yu L., Li X., Xue X., Liang X.;
RT   "Short-chain peptides identification of scorpion Buthus martensi Karsch
RT   venom by employing high orthogonal 2D-HPLC system and tandem mass
RT   spectrometry.";
RL   Proteomics 12:3076-3084(2012).
CC   -!- FUNCTION: Toxin with unknown function in healthy organisms. On glioma
CC       cells, interacts with chloride channels (probably ClC-3/CLCN3) and MMP2
CC       at the surface of glioma cells. This complex is then internalized via
CC       caveolae, thus inhibiting the chloride channels necessary for cell
CC       shrinkage and tumor propagation (By similarity).
CC       {ECO:0000250|UniProtKB:Q9UAD0}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000269|PubMed:22887697}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC       {ECO:0000305|PubMed:22887697}.
CC   -!- DOMAIN: The presence of a 'disulfide through disulfide knot'
CC       structurally defines this protein as a knottin.
CC       {ECO:0000250|UniProtKB:P15222}.
CC   -!- MASS SPECTROMETRY: Mass=3764.45; Method=Electrospray; Note=Monoisotopic
CC       mass.; Evidence={ECO:0000269|PubMed:22887697};
CC   -!- SIMILARITY: Belongs to the short scorpion toxin superfamily. Chloride
CC       channel inhibitor family. {ECO:0000255|PROSITE-ProRule:PRU00545}.
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DR   EMBL; AF327643; AAK16444.1; -; mRNA.
DR   PIR; A59356; A59356.
DR   AlphaFoldDB; Q9BJW4; -.
DR   SMR; Q9BJW4; -.
DR   GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR   GO; GO:0017081; F:chloride channel regulator activity; IEA:UniProtKB-KW.
DR   GO; GO:0090729; F:toxin activity; IEA:UniProtKB-KW.
DR   InterPro; IPR036574; Scorpion_toxin-like_sf.
DR   InterPro; IPR007958; Scorpion_toxinS_Cl_inh.
DR   Pfam; PF05294; Toxin_5; 1.
DR   SUPFAM; SSF57095; SSF57095; 1.
DR   PROSITE; PS51200; SHORT_SCORPION_CHLORIDE; 1.
PE   1: Evidence at protein level;
KW   Chloride channel impairing toxin; Disulfide bond;
KW   Ion channel impairing toxin; Knottin; Secreted; Signal; Toxin;
KW   Voltage-gated chloride channel impairing toxin.
FT   SIGNAL          1..24
FT                   /evidence="ECO:0000255"
FT   CHAIN           25..59
FT                   /note="Chlorotoxin-like peptide Bm12-b"
FT                   /evidence="ECO:0000269|PubMed:22887697"
FT                   /id="PRO_0000035316"
FT   DISULFID        25..42
FT                   /evidence="ECO:0000250|UniProtKB:P15222,
FT                   ECO:0000255|PROSITE-ProRule:PRU00545"
FT   DISULFID        28..49
FT                   /evidence="ECO:0000250|UniProtKB:P15222,
FT                   ECO:0000255|PROSITE-ProRule:PRU00545"
FT   DISULFID        39..54
FT                   /evidence="ECO:0000250|UniProtKB:P15222,
FT                   ECO:0000255|PROSITE-ProRule:PRU00545"
FT   DISULFID        43..56
FT                   /evidence="ECO:0000250|UniProtKB:P15222,
FT                   ECO:0000255|PROSITE-ProRule:PRU00545"
SQ   SEQUENCE   59 AA;  6484 MW;  C2BAABAFCB88D9EA CRC64;
     MKFLYGIVFI ALFLTVMFAT QTDGCGPCFT TDANMARKCR ECCGGNGKCF GPQCLCNRE