SIXP_MESMA
ID SIXP_MESMA Reviewed; 90 AA.
AC O77091;
DT 07-DEC-2004, integrated into UniProtKB/Swiss-Prot.
DT 01-NOV-1998, sequence version 1.
DT 25-MAY-2022, entry version 89.
DE RecName: Full=Beta-insect excitatory toxin BmK IT-AP {ECO:0000303|PubMed:10400300};
DE AltName: Full=Bm33-I;
DE AltName: Full=Insect toxin-analgesic peptide {ECO:0000303|PubMed:10400300};
DE Short=BmKITAP {ECO:0000303|PubMed:10400300};
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 19-90, FUNCTION, AND
RP SUBCELLULAR LOCATION.
RC TISSUE=Venom, and Venom gland;
RX PubMed=10400300; DOI=10.1016/s0041-0101(98)00253-0;
RA Xiong Y.-M., Lan Z.-D., Wang M., Liu B., Liu X.-Q., Fei H., Xu L.-G.,
RA Xia Q.-C., Wang C.-G., Wang D.-C., Chi C.-W.;
RT "Molecular characterization of a new excitatory insect neurotoxin with an
RT analgesic effect on mice from the scorpion Buthus martensi Karsch.";
RL Toxicon 37:1165-1180(1999).
RN [2]
RP NUCLEOTIDE SEQUENCE [MRNA].
RC TISSUE=Venom gland;
RA Li W., Zhu S.;
RL Submitted (JUN-1999) to the EMBL/GenBank/DDBJ databases.
RN [3]
RP PROTEIN SEQUENCE OF 19-90, ELECTROPHYSIOLOGICAL CHARACTERIZATION, TOXIC
RP DOSE, MASS SPECTROMETRY, AND SUBCELLULAR LOCATION.
RC TISSUE=Venom;
RX PubMed=11042276; DOI=10.1016/s0014-5793(00)02099-8;
RA Escoubas P., Stankiewicz M., Takaoka T., Pelhate M., Romi-Lebrun R.,
RA Wu F.Q., Nakajima T.;
RT "Sequence and electrophysiological characterization of two insect-selective
RT excitatory toxins from the venom of the Chinese scorpion Buthus martensi.";
RL FEBS Lett. 483:175-180(2000).
RN [4]
RP X-RAY CRYSTALLOGRAPHY (2.6 ANGSTROMS) OF 19-90, AND DISULFIDE BONDS.
RX PubMed=10944339; DOI=10.1107/s0907444900006004;
RA Guan R.J., Liu X.Q., Liu B., Wang M., Wang D.C.;
RT "Crystallization and preliminary X-ray analyses of insect neurotoxins with
RT analgesic effect from the scorpion Buthus martensii Karsch.";
RL Acta Crystallogr. D 56:1012-1014(2000).
CC -!- FUNCTION: Excitatory insect beta-toxins induce a spastic paralysis
CC (PubMed:10400300). They bind voltage-independently at site-4 of sodium
CC channels (Nav) and shift the voltage of activation toward more negative
CC potentials thereby affecting sodium channel activation and promoting
CC spontaneous and repetitive firing. In vivo, induces paralysis on
CC insects (PubMed:11042276). When tested on mice, it does not show
CC toxicity but has an analgesic effect (PubMed:10400300).
CC -!- SUBCELLULAR LOCATION: Secreted {ECO:0000269|PubMed:10400300,
CC ECO:0000269|PubMed:11042276}.
CC -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC {ECO:0000305|PubMed:10400300, ECO:0000305|PubMed:11042276}.
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=8149.39; Method=MALDI;
CC Evidence={ECO:0000269|PubMed:11042276};
CC -!- TOXIC DOSE: PD(50) is 0.49 ng/mg in Gryllus bimaculatus crickets.
CC {ECO:0000269|PubMed:11042276}.
CC -!- SIMILARITY: Belongs to the long (4 C-C) scorpion toxin superfamily.
CC Sodium channel inhibitor family. Beta subfamily. {ECO:0000305}.
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DR EMBL; AF055672; AAC61256.1; -; Genomic_DNA.
DR EMBL; AF156171; AAF29464.1; -; mRNA.
DR PDB; 1T0Z; X-ray; 2.60 A; A/B=19-90.
DR PDBsum; 1T0Z; -.
DR AlphaFoldDB; O77091; -.
DR SMR; O77091; -.
DR EvolutionaryTrace; O77091; -.
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; IPR002061; Scorpion_toxinL/defensin.
DR Pfam; PF00537; Toxin_3; 1.
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; Signal; Toxin;
KW Voltage-gated sodium channel impairing toxin.
FT SIGNAL 1..18
FT /evidence="ECO:0000305|PubMed:10400300,
FT ECO:0000305|PubMed:11042276"
FT CHAIN 19..90
FT /note="Beta-insect excitatory toxin BmK IT-AP"
FT /evidence="ECO:0000269|PubMed:10400300,
FT ECO:0000269|PubMed:11042276"
FT /id="PRO_0000035211"
FT DOMAIN 20..83
FT /note="LCN-type CS-alpha/beta"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU01210"
FT DISULFID 34..55
FT /evidence="ECO:0000269|PubMed:10944339,
FT ECO:0007744|PDB:1T0Z"
FT DISULFID 40..60
FT /evidence="ECO:0000269|PubMed:10944339,
FT ECO:0007744|PDB:1T0Z"
FT DISULFID 44..62
FT /evidence="ECO:0000269|PubMed:10944339,
FT ECO:0007744|PDB:1T0Z"
FT DISULFID 56..82
FT /evidence="ECO:0000269|PubMed:10944339,
FT ECO:0007744|PDB:1T0Z"
FT STRAND 20..25
FT /evidence="ECO:0007829|PDB:1T0Z"
FT HELIX 37..48
FT /evidence="ECO:0007829|PDB:1T0Z"
FT STRAND 51..56
FT /evidence="ECO:0007829|PDB:1T0Z"
FT STRAND 59..65
FT /evidence="ECO:0007829|PDB:1T0Z"
FT HELIX 76..83
FT /evidence="ECO:0007829|PDB:1T0Z"
SQ SEQUENCE 90 AA; 10225 MW; ED240D0BCF637EA2 CRC64;
MKFFLIFLVI FPIMGVLGKK NGYAVDSSGK VAECLFNNYC NNECTKVYYA DKGYCCLLKC
YCFGLADDKP VLDIWDSTKN YCDVQIIDLS
