ID   TXHM2_HERML             Reviewed;          40 AA.
AC   P85506;
DT   14-OCT-2008, integrated into UniProtKB/Swiss-Prot.
DT   14-OCT-2008, sequence version 1.
DT   25-MAY-2022, entry version 27.
DE   RecName: Full=Mu-thomitoxin-Hme1b {ECO:0000305};
DE            Short=Mu-TMTX-Hme1b {ECO:0000305};
DE   AltName: Full=Neurotoxin Hm-2 {ECO:0000303|PubMed:18606177};
OS   Heriaeus mellotteei (Crab spider) (Heriaeus oblongus).
OC   Eukaryota; Metazoa; Ecdysozoa; Arthropoda; Chelicerata; Arachnida; Araneae;
OC   Araneomorphae; Entelegynae; Dionycha; Thomisidae; Heriaeus.
OX   NCBI_TaxID=504442;
RN   [1]
RP   PROTEIN SEQUENCE, FUNCTION, DISULFIDE BONDS, AND MASS SPECTROMETRY.
RC   TISSUE=Venom;
RX   PubMed=18606177; DOI=10.1016/j.toxicon.2008.05.018;
RA   Billen B., Vassilevski A., Nikolsky A., Tytgat J., Grishin E.;
RT   "Two novel sodium channel inhibitors from Heriaeus melloteei spider venom
RT   differentially interacting with mammalian channel's isoforms.";
RL   Toxicon 52:309-317(2008).
RN   [2]
RP   PROTEIN SEQUENCE, FUNCTION, DISULFIDE BONDS, AND MASS SPECTROMETRY.
RC   TISSUE=Venom;
RX   DOI=10.1134/S1990747809030027;
RA   Nikolsky A., Billen B., Vassilevski A., Filkin S., Tytgat J., Grishin E.;
RT   "Voltage-gated sodium channels are targets for toxins from the venom of the
RT   spider Heriaeus melloteei.";
RL   Biochemistry (Mosc.) Suppl. Series A 3:245-253(2009).
CC   -!- FUNCTION: Blocks the Nav1.2/SCN2A, Nav1.4/SCN4A, Nav1.5/SCN5A and
CC       Nav1.6/SCN8A sodium channels. Shows a slight preference for the Nav1.2
CC       and Nav1.4 channels. Reduces the peak amplitude of the sodium current
CC       and negatively shifts the steady-state inactivation process. Does not
CC       shift the threshold potential of activation or the voltage
CC       corresponding to maximal current. Does not change the reversal
CC       potential of the sodium current. May act on site 1 of the receptor.
CC       {ECO:0000269|PubMed:18606177, ECO:0000269|Ref.2}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000269|PubMed:18606177}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland. {ECO:0000305}.
CC   -!- DOMAIN: The presence of a 'disulfide through disulfide knot'
CC       structurally defines this protein as a knottin.
CC       {ECO:0000250|UniProtKB:P56714}.
CC   -!- PTM: Contains 3 disulfide bonds.
CC   -!- MASS SPECTROMETRY: Mass=4555.3; Method=MALDI;
CC       Evidence={ECO:0000269|PubMed:18606177};
CC   -!- MISCELLANEOUS: Does not inhibit the sodium channel Nav1.8/SCN10A.
CC   -!- SIMILARITY: Belongs to the neurotoxin 19 (CSTX) family. {ECO:0000305}.
CC   ---------------------------------------------------------------------------
CC   Copyrighted by the UniProt Consortium, see https://www.uniprot.org/terms
CC   Distributed under the Creative Commons Attribution (CC BY 4.0) License
CC   ---------------------------------------------------------------------------
DR   AlphaFoldDB; P85506; -.
DR   SMR; P85506; -.
DR   ArachnoServer; AS000760; mu-thomitoxin-Hme1b.
DR   GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR   GO; GO:0017080; F:sodium channel regulator activity; IEA:UniProtKB-KW.
DR   GO; GO:0090729; F:toxin activity; IEA:UniProtKB-KW.
PE   1: Evidence at protein level;
KW   Direct protein sequencing; Disulfide bond; Ion channel impairing toxin;
KW   Knottin; Neurotoxin; Secreted; Toxin;
KW   Voltage-gated sodium channel impairing toxin.
FT   PEPTIDE         1..40
FT                   /note="Mu-thomitoxin-Hme1b"
FT                   /id="PRO_0000352651"
FT   DISULFID        2..18
FT                   /evidence="ECO:0000250|UniProtKB:P56714"
FT   DISULFID        9..22
FT                   /evidence="ECO:0000250|UniProtKB:P56714"
FT   DISULFID        17..33
FT                   /evidence="ECO:0000250|UniProtKB:P56714"
SQ   SEQUENCE   40 AA;  4561 MW;  45875BBA9B0A22D5 CRC64;
     GCIPSFGECA WFSGESCCTG ICKWVFFTSK FMCRRVWGKD