ID   TX325_SEGFL             Reviewed;          49 AA.
AC   P58605;
DT   23-JAN-2002, integrated into UniProtKB/Swiss-Prot.
DT   23-JAN-2002, sequence version 1.
DT   25-MAY-2022, entry version 43.
DE   RecName: Full=Omega-segestritoxin-Sf1a;
DE            Short=Omega-SGTX-Sf1a;
DE   AltName: Full=Toxin SNX-325;
OS   Segestria florentina (Tube-web spider) (Segestria gracilis).
OC   Eukaryota; Metazoa; Ecdysozoa; Arthropoda; Chelicerata; Arachnida; Araneae;
OC   Araneomorphae; Haplogynae; Dysderoidea; Segestriidae; Segestria.
OX   NCBI_TaxID=31925;
RN   [1]
RP   PROTEIN SEQUENCE, SYNTHESIS, AND FUNCTION.
RC   TISSUE=Venom;
RX   PubMed=7541240; DOI=10.1021/bi00026a015;
RA   Newcomb R., Palma A., Fox J., Gaur S., Lau K., Chung D., Cong R.,
RA   Bell J.R., Horne B., Nadasdi L.;
RT   "SNX-325, a novel calcium antagonist from the spider Segestria
RT   florentina.";
RL   Biochemistry 34:8341-8347(1995).
CC   -!- FUNCTION: Potent and selective blocker of N-type voltage-gated calcium
CC       channels (Cav2.2/CACNA1B). Also blocks vertebrate Cav2.1/CACNA1A (P/Q-
CC       type) and Cav1.2/CACNA1C (L-type) channels at very high concentration
CC       (2 micromolar). {ECO:0000269|PubMed:7541240}.
CC   -!- SUBCELLULAR LOCATION: Secreted.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC   -!- DOMAIN: The presence of a 'disulfide through disulfide knot'
CC       structurally defines this protein as a knottin. {ECO:0000305}.
CC   -!- MISCELLANEOUS: This toxin does not inhibit sodium and potassium
CC       channels. {ECO:0000305|PubMed:7541240}.
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; P58605; -.
DR   ArachnoServer; AS000256; omega-segestritoxin-Sf1a.
DR   GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR   GO; GO:0005246; F:calcium channel regulator activity; IEA:UniProtKB-KW.
DR   GO; GO:0090729; F:toxin activity; IEA:UniProtKB-KW.
PE   1: Evidence at protein level;
KW   Calcium channel impairing toxin; Direct protein sequencing; Disulfide bond;
KW   Ion channel impairing toxin; Knottin; Neurotoxin; Secreted; Toxin;
KW   Voltage-gated calcium channel impairing toxin.
FT   CHAIN           1..49
FT                   /note="Omega-segestritoxin-Sf1a"
FT                   /id="PRO_0000087674"
FT   DISULFID        3..22
FT                   /evidence="ECO:0000305"
FT   DISULFID        10..27
FT                   /evidence="ECO:0000305"
FT   DISULFID        21..48
FT                   /evidence="ECO:0000305"
FT   DISULFID        29..46
FT                   /evidence="ECO:0000305"
SQ   SEQUENCE   49 AA;  5594 MW;  9BA142AC0263F6FD CRC64;
     GSCIESGKSC THSRSMKNGL CCPKSRCNCR QIQHRHDYLG KRKYSCRCS