ID   TX3_CERMR               Reviewed;          39 AA.
AC   P84509;
DT   25-OCT-2005, integrated into UniProtKB/Swiss-Prot.
DT   25-OCT-2005, sequence version 1.
DT   25-MAY-2022, entry version 52.
DE   RecName: Full=Beta-theraphotoxin-Cm2a;
DE            Short=Beta-TRTX-Cm2a;
DE   AltName: Full=Ceratotoxin-3 {ECO:0000303|PubMed:16267209};
DE            Short=CcoTx3 {ECO:0000303|PubMed:16267209};
OS   Ceratogyrus marshalli (Straighthorned baboon tarantula) (Ceratogyrus
OS   cornuatus).
OC   Eukaryota; Metazoa; Ecdysozoa; Arthropoda; Chelicerata; Arachnida; Araneae;
OC   Mygalomorphae; Theraphosidae; Ceratogyrus.
OX   NCBI_TaxID=316287;
RN   [1]
RP   PROTEIN SEQUENCE, FUNCTION, BIOASSAY, SUBCELLULAR LOCATION, MASS
RP   SPECTROMETRY, AND AMIDATION AT PHE-39.
RC   TISSUE=Venom;
RX   PubMed=16267209; DOI=10.1124/mol.105.015941;
RA   Bosmans F., Rash L., Zhu S., Diochot S., Lazdunski M., Escoubas P.,
RA   Tytgat J.;
RT   "Four novel tarantula toxins as selective modulators of voltage-gated
RT   sodium channel subtypes.";
RL   Mol. Pharmacol. 69:419-429(2006).
CC   -!- FUNCTION: Inhibits mammalian voltage-gated sodium channel subtypes
CC       Nav1.5/SCN5A and Nav1.8/SCN10A by shifting the voltage dependence of
CC       channel activation to more depolarized potentials and by blocking the
CC       inward component of the sodium current. In vivo, this toxin causes
CC       erect, elevated tail, initial partial ataxia, followed by recovery over
CC       approximately 1 hour after injection and the progressive development of
CC       shaking. Although paralysis subsides, the body tremors never cease and
CC       persist until the end of the experiment. {ECO:0000269|PubMed:16267209}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000269|PubMed:16267209}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC       {ECO:0000305|PubMed:16267209}.
CC   -!- DOMAIN: The presence of a 'disulfide through disulfide knot'
CC       structurally defines this protein as a knottin.
CC       {ECO:0000250|UniProtKB:P56855}.
CC   -!- MASS SPECTROMETRY: Mass=4321.84; Method=MALDI;
CC       Evidence={ECO:0000269|PubMed:16267209};
CC   -!- SIMILARITY: Belongs to the neurotoxin 10 (Hwtx-1) family. 47 subfamily.
CC       {ECO:0000305}.
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DR   AlphaFoldDB; P84509; -.
DR   SMR; P84509; -.
DR   ArachnoServer; AS000272; beta-theraphotoxin-Cm2a.
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:0044489; P:negative regulation of voltage-gated sodium channel activity in another organism; IDA:UniProtKB.
DR   InterPro; IPR011696; Huwentoxin-1.
DR   Pfam; PF07740; Toxin_12; 1.
PE   1: Evidence at protein level;
KW   Amidation; Direct protein sequencing; Disulfide bond;
KW   Ion channel impairing toxin; Knottin; Neurotoxin; Secreted; Toxin;
KW   Voltage-gated sodium channel impairing toxin.
FT   PEPTIDE         1..39
FT                   /note="Beta-theraphotoxin-Cm2a"
FT                   /evidence="ECO:0000269|PubMed:16267209"
FT                   /id="PRO_0000045002"
FT   MOD_RES         39
FT                   /note="Phenylalanine amide"
FT                   /evidence="ECO:0000269|PubMed:16267209"
FT   DISULFID        7..21
FT                   /evidence="ECO:0000250|UniProtKB:P56855"
FT   DISULFID        14..26
FT                   /evidence="ECO:0000250|UniProtKB:P56855"
FT   DISULFID        20..33
FT                   /evidence="ECO:0000250|UniProtKB:P56855"
SQ   SEQUENCE   39 AA;  4332 MW;  2EBF6899D00ED41C CRC64;
     GVDKEGCRKL LGGCTIDDDC CPHLGCNKKY WHCGWDGTF