ID   SIX1_ISOVI              Reviewed;          70 AA.
AC   P0C5H1;
DT   02-OCT-2007, integrated into UniProtKB/Swiss-Prot.
DT   02-OCT-2007, sequence version 1.
DT   25-MAY-2022, entry version 38.
DE   RecName: Full=Beta-toxin Isom1;
DE   AltName: Full=IsomTx1;
OS   Isometrus vittatus (Bark scorpion) (Reddyanus vittatus).
OC   Eukaryota; Metazoa; Ecdysozoa; Arthropoda; Chelicerata; Arachnida;
OC   Scorpiones; Buthida; Buthoidea; Buthidae; Isometrus.
OX   NCBI_TaxID=463567;
RN   [1]
RP   PROTEIN SEQUENCE, FUNCTION, AND MASS SPECTROMETRY.
RC   TISSUE=Venom;
RX   PubMed=12875873; DOI=10.1016/s0041-0101(03)00071-0;
RA   Coronas F.V., Stankiewicz M., Batista C.V.F., Giraud S., Alam J.M.,
RA   Possani L.D., Mebs D., Pelhate M.;
RT   "Primary structure and electrophysiological characterization of two almost
RT   identical isoforms of toxin from Isometrus vittatus (family: Buthidae)
RT   scorpion venom.";
RL   Toxicon 41:989-997(2003).
CC   -!- FUNCTION: Excitatory insect beta-toxins induce a spastic paralysis (By
CC       similarity). 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. {ECO:0000250,
CC       ECO:0000269|PubMed:12875873}.
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=7899.50; Method=Electrospray;
CC       Evidence={ECO:0000269|PubMed:12875873};
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   AlphaFoldDB; P0C5H1; -.
DR   SMR; P0C5H1; -.
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   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   Direct protein sequencing; Disulfide bond; Ion channel impairing toxin;
KW   Neurotoxin; Secreted; Toxin; Voltage-gated sodium channel impairing toxin.
FT   CHAIN           1..70
FT                   /note="Beta-toxin Isom1"
FT                   /id="PRO_0000306086"
FT   DOMAIN          2..65
FT                   /note="LCN-type CS-alpha/beta"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01210"
FT   DISULFID        16..37
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01210"
FT   DISULFID        22..42
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01210"
FT   DISULFID        26..44
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01210"
FT   DISULFID        38..64
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01210"
SQ   SEQUENCE   70 AA;  7908 MW;  D9BCF504732CB6D4 CRC64;
     KKNGYAVDSS GKAPECLLSN YCNNECTKVH YADKGYCCLL SCYCFGLSDD KKVLEISDTR
     KKYCDYTIIN