ID   SFI4_SEGFL              Reviewed;          46 AA.
AC   P61098;
DT   26-APR-2004, integrated into UniProtKB/Swiss-Prot.
DT   26-APR-2004, sequence version 1.
DT   25-MAY-2022, entry version 36.
DE   RecName: Full=Mu-segestritoxin-Sf1d {ECO:0000305};
DE            Short=Mu-SGTX-Sf1d {ECO:0000305};
DE   AltName: Full=Toxin SFI4 {ECO:0000303|PubMed:11689233};
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   NUCLEOTIDE SEQUENCE [MRNA].
RC   TISSUE=Venom gland;
RX   PubMed=11689233; DOI=10.1016/s0041-0101(01)00181-7;
RA   Lipkin A., Kozlov S., Nosyreva E., Blake A., Windass J.D., Grishin E.;
RT   "Novel insecticidal toxins from the venom of the spider Segestria
RT   florentina.";
RL   Toxicon 40:125-130(2002).
CC   -!- FUNCTION: Insecticidal toxin. It inhibits insect voltage-gated sodium
CC       channels (Nav) by partially blocking the channel pore in DUM neurons
CC       from the American cockroach, not by acting as a gating modifier. The
CC       inhibition is only partially reversible after prolonged washout. In
CC       vivo, the toxin causes flaccid paralysis followed by death when
CC       injected into Heliothis virescens larvae. It also causes uncoordinated
CC       movements followed by full paralysis to sheep blowflies (Lucilia
CC       cuprina). When the toxin is fused to snowdrop lectin, it is orally
CC       active against larvae of the tomato moth (Laconobia oleracea), the rice
CC       brown planthopper (Nilaparvata lugens), and the peach-potato aphid
CC       (Myzus persicae). {ECO:0000250|UniProtKB:P61095}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000250|UniProtKB:P61095}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC       {ECO:0000305|PubMed:11689233}.
CC   -!- DOMAIN: The presence of a 'disulfide through disulfide knot'
CC       structurally defines this protein as a knottin.
CC       {ECO:0000250|UniProtKB:P61095}.
CC   -!- SIMILARITY: Belongs to the neurotoxin 16 (SFI) family. {ECO:0000305}.
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DR   AlphaFoldDB; P61098; -.
DR   SMR; P61098; -.
DR   ArachnoServer; AS000119; mu-segestritoxin-Sf1d.
DR   GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR   GO; GO:0090729; F:toxin activity; IEA:UniProtKB-KW.
DR   InterPro; IPR012633; Toxin_28.
DR   Pfam; PF08115; Toxin_28; 1.
PE   3: Inferred from homology;
KW   Disulfide bond; Knottin; Secreted; Toxin.
FT   CHAIN           1..46
FT                   /note="Mu-segestritoxin-Sf1d"
FT                   /evidence="ECO:0000305|PubMed:11689233"
FT                   /id="PRO_0000087619"
FT   REGION          31..33
FT                   /note="Keys region for toxin activity"
FT                   /evidence="ECO:0000250|UniProtKB:P61095"
FT   DISULFID        3..19
FT                   /evidence="ECO:0000250|UniProtKB:P61095"
FT   DISULFID        10..22
FT                   /evidence="ECO:0000250|UniProtKB:P61095"
FT   DISULFID        18..42
FT                   /evidence="ECO:0000250|UniProtKB:P61095"
FT   DISULFID        24..40
FT                   /evidence="ECO:0000250|UniProtKB:P61095"
SQ   SEQUENCE   46 AA;  5002 MW;  BFB8E8A0542E785F CRC64;
     KECMVDGTVC YIHNHNDCCG SCLCLNGPIA RPWKMMVGNC KCGPKA