SCX4_MESMA
ID SCX4_MESMA Reviewed; 64 AA.
AC P58328;
DT 24-OCT-2001, integrated into UniProtKB/Swiss-Prot.
DT 24-OCT-2001, sequence version 1.
DT 03-AUG-2022, entry version 98.
DE RecName: Full=Alpha-like toxin BmK-M4;
DE Short=BmK4;
DE Short=BmKM4;
DE Short=Bmk M4 {ECO:0000303|PubMed:10493862};
DE AltName: Full=BmK-IV;
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, TOXIC DOSE, AND SUBCELLULAR LOCATION.
RC TISSUE=Venom;
RX PubMed=9203297; DOI=10.1016/s0041-0101(96)00146-8;
RA Luo M.-J., Xiong Y.-M., Wang M., Wang D.-C., Chi C.-W.;
RT "Purification and sequence determination of a new neutral mammalian
RT neurotoxin from the scorpion Buthus martensii Karsch.";
RL Toxicon 35:723-731(1997).
RN [2]
RP CRYSTALLIZATION.
RC TISSUE=Venom;
RX PubMed=10089445; DOI=10.1107/s0907444998006593;
RA Li H.-M., Zhao T., Jin L., Wang M., Zhang Y., Wang D.-C.;
RT "A series of bioactivity-variant neurotoxins from scorpion Buthus martensii
RT Karsch: purification, crystallization and crystallographic analysis.";
RL Acta Crystallogr. D 55:341-344(1999).
RN [3] {ECO:0000312|PDB:1SN4}
RP X-RAY CRYSTALLOGRAPHY (1.3 ANGSTROMS).
RX PubMed=10493862; DOI=10.1006/jmbi.1999.3036;
RA He X.-L., Li H.-M., Zeng Z.-H., Liu X.-Q., Wang M., Wang D.-C.;
RT "Crystal structures of two alpha-like scorpion toxins: non-proline cis
RT peptide bonds and implications for new binding site selectivity on the
RT sodium channel.";
RL J. Mol. Biol. 292:125-135(1999).
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 against
CC mammals.
CC -!- SUBCELLULAR LOCATION: Secreted {ECO:0000269|PubMed:9203297}.
CC -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC {ECO:0000305|PubMed:9203297}.
CC -!- DOMAIN: Has the structural arrangement of an alpha-helix connected to
CC antiparallel beta-sheets by disulfide bonds (CS-alpha/beta).
CC {ECO:0000269|PubMed:10493862}.
CC -!- TOXIC DOSE: LD(50) is 4 mg/kg +/- 0.25 by intravenous injection into
CC mice. {ECO:0000269|PubMed:9203297}.
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; 1SN4; X-ray; 1.30 A; A=1-64.
DR PDBsum; 1SN4; -.
DR AlphaFoldDB; P58328; -.
DR SMR; P58328; -.
DR EvolutionaryTrace; P58328; -.
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..64
FT /note="Alpha-like toxin BmK-M4"
FT /evidence="ECO:0000269|PubMed:9203297"
FT /id="PRO_0000066751"
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:0000269|PubMed:10493862,
FT ECO:0007744|PDB:1SN4"
FT DISULFID 16..36
FT /evidence="ECO:0000269|PubMed:10493862,
FT ECO:0007744|PDB:1SN4"
FT DISULFID 22..46
FT /evidence="ECO:0000269|PubMed:10493862,
FT ECO:0007744|PDB:1SN4"
FT DISULFID 26..48
FT /evidence="ECO:0000269|PubMed:10493862,
FT ECO:0007744|PDB:1SN4"
FT STRAND 2..8
FT /evidence="ECO:0007829|PDB:1SN4"
FT TURN 9..11
FT /evidence="ECO:0007829|PDB:1SN4"
FT HELIX 19..28
FT /evidence="ECO:0007829|PDB:1SN4"
FT STRAND 32..40
FT /evidence="ECO:0007829|PDB:1SN4"
FT STRAND 43..51
FT /evidence="ECO:0007829|PDB:1SN4"
SQ SEQUENCE 64 AA; 7021 MW; 20C7427C1C74DABB CRC64;
VRDAYIAKPE NCVYHCAGNE GCNKLCTDNG AESGYCQWGG RYGNACWCIK LPDDVPIRVP
GKCH
