ID   SCX3_CENBA              Reviewed;          66 AA.
AC   C0HLR5;
DT   07-OCT-2020, integrated into UniProtKB/Swiss-Prot.
DT   07-OCT-2020, sequence version 1.
DT   03-AUG-2022, entry version 6.
DE   RecName: Full=Beta-toxin Cb3 {ECO:0000303|PubMed:32479835};
OS   Centruroides baergi (Scorpion) (Centruroides nigrovariatus baergi).
OC   Eukaryota; Metazoa; Ecdysozoa; Arthropoda; Chelicerata; Arachnida;
OC   Scorpiones; Buthida; Buthoidea; Buthidae; Centruroides.
OX   NCBI_TaxID=329350 {ECO:0000303|PubMed:32479835};
RN   [1] {ECO:0000305}
RP   PROTEIN SEQUENCE, FUNCTION, SUBCELLULAR LOCATION, MASS SPECTROMETRY, AND
RP   TOXIC DOSE.
RC   TISSUE=Venom {ECO:0000303|PubMed:32479835};
RX   PubMed=32479835; DOI=10.1016/j.toxicon.2020.05.021;
RA   Gomez-Ramirez I.V., Riano-Umbarila L., Olamendi-Portugal T.,
RA   Restano-Cassulini R., Possani L.D., Becerril B.;
RT   "Biochemical, electrophysiological and immunological characterization of
RT   the venom from Centruroides baergi, a new scorpion species of medical
RT   importance in Mexico.";
RL   Toxicon 184:10-18(2020).
CC   -!- FUNCTION: Beta toxins bind voltage-independently at site-4 of sodium
CC       channels (Nav) and reduces peak current and shifts the voltage of
CC       activation toward more negative potentials thereby affecting sodium
CC       channel activation and promoting spontaneous and repetitive firing
CC       (PubMed:32479835). Has an inhibitory effect on voltage-gated sodium
CC       channels hNav1.1/SCN1A, hNav1.2/SCN2A, hNav1.4/SCN4A and hNav1.6/SCN8A
CC       (PubMed:32479835). Reduces the peak current of hNav1.5/SCN5A but does
CC       not shift its voltage of activation (PubMed:32479835). Also affects the
CC       inactivation processes of hNav1.1/SCN1A, hNav1.4/SCN4A, hNav1.5/SCN5A
CC       and hNav1.6/SCN8A (PubMed:32479835). This toxin is active against
CC       mammals and lethal to mice (PubMed:32479835).
CC       {ECO:0000269|PubMed:32479835}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000269|PubMed:32479835}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC       {ECO:0000305|PubMed:32479835}.
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=7775.7; Mass_error=1; Method=Electrospray;
CC       Evidence={ECO:0000269|PubMed:32479835};
CC   -!- TOXIC DOSE: LD(50) is 0.5 ug/mouse by intraperitoneal injection into
CC       mice. {ECO:0000269|PubMed:32479835}.
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; C0HLR5; -.
DR   SMR; C0HLR5; -.
DR   ABCD; C0HLR5; 2 sequenced antibodies.
DR   GO; GO:0005615; C:extracellular space; IDA:UniProtKB.
DR   GO; GO:0019871; F:sodium channel inhibitor activity; IDA:UniProtKB.
DR   GO; GO:0090729; F:toxin activity; IDA:UniProtKB.
DR   GO; GO:0006952; P:defense response; IDA:UniProtKB.
DR   GO; GO:0044493; P:envenomation resulting in negative regulation of voltage-gated sodium channel activity in another organism; IDA:UniProtKB.
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   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   Direct protein sequencing; Disulfide bond; Ion channel impairing toxin;
KW   Neurotoxin; Secreted; Toxin; Voltage-gated sodium channel impairing toxin.
FT   CHAIN           1..66
FT                   /note="Beta-toxin Cb3"
FT                   /id="PRO_0000450849"
FT   DOMAIN          1..66
FT                   /note="LCN-type CS-alpha/beta"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01210"
FT   DISULFID        12..65
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01210"
FT   DISULFID        16..41
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01210"
FT   DISULFID        25..46
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01210"
FT   DISULFID        29..48
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01210"
SQ   SEQUENCE   66 AA;  7783 MW;  A8C7634CCC83E423 CRC64;
     KEGYIVNYYD GCKYPCVKLG DNDYCLRECR LRYYKSAGGY CYAFACWCTH LYEQAVVWPL
     PNKTCL