ID   SCX7_MESMA              Reviewed;          66 AA.
AC   P59854;
DT   19-SEP-2003, integrated into UniProtKB/Swiss-Prot.
DT   19-SEP-2003, sequence version 1.
DT   03-AUG-2022, entry version 81.
DE   RecName: Full=Alpha-like toxin BmK-M7;
DE            Short=BmKM7;
DE            Short=Bmk M7;
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   PROTEIN SEQUENCE, X-RAY CRYSTALLOGRAPHY (1.4 ANGSTROMS), AND MASS
RP   SPECTROMETRY.
RX   PubMed=15321715; DOI=10.1016/j.jmb.2004.06.067;
RA   Guan R.-J., Xiang Y., He X.-L., Wang C.-G., Wang M., Zhang Y.,
RA   Sundberg E.J., Wang D.-C.;
RT   "Structural mechanism governing cis and trans isomeric states and an
RT   intramolecular switch for cis/trans isomerization of a non-proline peptide
RT   bond observed in crystal structures of scorpion toxins.";
RL   J. Mol. Biol. 341:1189-1204(2004).
RN   [2]
RP   FUNCTION, AND CRYSTALLIZATION.
RC   TISSUE=Venom;
RX   PubMed=12370033; DOI=10.2174/0929866023408562;
RA   Guan R.-J., He X.-L., Wang M., Ye X., Li G.-P., Wang D.-C.;
RT   "Purification, crystallization and initial structural solution of a new
RT   alpha-like toxin with cardiac toxicity from scorpion Buthus martensii
RT   Karsch.";
RL   Protein Pept. Lett. 9:441-449(2002).
CC   -!- FUNCTION: Alpha toxins bind voltage-independently at site-3 of sodium
CC       channels (Nav) and inhibit the inactivation of the activated channels,
CC       thereby blocking neuronal transmission. This toxin is active on both
CC       mammals and insects. It can be considered as a cardiotoxin, as it can
CC       bind to human cardiac sodium channel and modify its normal properties.
CC       {ECO:0000269|PubMed:12370033}.
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=7237.4; Method=MALDI;
CC       Evidence={ECO:0000269|PubMed:15321715};
CC   -!- MISCELLANEOUS: Exists in two forms, due to cis-trans isomerization at
CC       9-Pro-His-10.
CC   -!- SIMILARITY: Belongs to the long (4 C-C) scorpion toxin superfamily.
CC       Sodium channel inhibitor family. Alpha subfamily. {ECO:0000305}.
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DR   PDB; 1KV0; X-ray; 1.40 A; A/B=1-66.
DR   PDBsum; 1KV0; -.
DR   AlphaFoldDB; P59854; -.
DR   SMR; P59854; -.
DR   EvolutionaryTrace; P59854; -.
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   3D-structure; Direct protein sequencing; Disulfide bond;
KW   Ion channel impairing toxin; Neurotoxin; Secreted; Toxin;
KW   Voltage-gated sodium channel impairing toxin.
FT   CHAIN           1..66
FT                   /note="Alpha-like toxin BmK-M7"
FT                   /id="PRO_0000066752"
FT   DOMAIN          2..64
FT                   /note="LCN-type CS-alpha/beta"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01210"
FT   DISULFID        12..63
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01210"
FT   DISULFID        16..36
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01210"
FT   DISULFID        22..46
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01210"
FT   DISULFID        26..48
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01210"
FT   STRAND          2..8
FT                   /evidence="ECO:0007829|PDB:1KV0"
FT   TURN            9..11
FT                   /evidence="ECO:0007829|PDB:1KV0"
FT   HELIX           19..28
FT                   /evidence="ECO:0007829|PDB:1KV0"
FT   STRAND          32..38
FT                   /evidence="ECO:0007829|PDB:1KV0"
FT   STRAND          40..51
FT                   /evidence="ECO:0007829|PDB:1KV0"
SQ   SEQUENCE   66 AA;  7244 MW;  F58F7B604D9237F5 CRC64;
     VRDGYIALPH NCAYGCLNNE YCNNLCTKDG AKIGYCNIVG KYGNACWCIQ LPDNVPIRVP
     GRCHPA