ID   TOG3B_AGEAP             Reviewed;          76 AA.
AC   P81744;
DT   01-JUN-2001, integrated into UniProtKB/Swiss-Prot.
DT   01-JUN-2001, sequence version 1.
DT   25-MAY-2022, entry version 66.
DE   RecName: Full=Omega-agatoxin-Aa3b;
DE            Short=Omega-AGTX-Aa3b;
DE   AltName: Full=Omega-agatoxin IIIB;
DE            Short=Omega-Aga-IIIB;
DE   AltName: Full=Omega-agatoxin-3B;
OS   Agelenopsis aperta (North American funnel-web spider) (Agelenopsis
OS   gertschi).
OC   Eukaryota; Metazoa; Ecdysozoa; Arthropoda; Chelicerata; Arachnida; Araneae;
OC   Araneomorphae; Entelegynae; Agelenidae; Agelenopsis.
OX   NCBI_TaxID=6908;
RN   [1]
RP   PROTEIN SEQUENCE, VARIANTS SER-29 AND ARG-35, AND FUNCTION.
RC   TISSUE=Venom;
RX   PubMed=8172884; DOI=10.1021/bi00183a013;
RA   Ertel E.A., Warren V.A., Adams M.E., Griffin P.R., Cohen C.J., Smith M.M.;
RT   "Type III omega-agatoxins: a family of probes for similar binding sites on
RT   L- and N-type calcium channels.";
RL   Biochemistry 33:5098-5108(1994).
CC   -!- FUNCTION: Omega-agatoxins are antagonists of voltage-gated calcium
CC       channels. This toxin blocks calcium channels in insect central neurons
CC       but not at peripheral neuromuscular junctions. In vertebrates, it is
CC       broadly active against all high-threshold Cav1/CACNA1 channels and
CC       Cav2.2/CACNA1B channels. {ECO:0000269|PubMed:8172884}.
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 Cav3 (T-type) channels.
CC   -!- SIMILARITY: Belongs to the neurotoxin 04 (omega-agtx) family. 03 (type
CC       II/III omega-agtx) subfamily. {ECO:0000305}.
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DR   PIR; B54252; B54252.
DR   PIR; C54252; C54252.
DR   PIR; D54252; D54252.
DR   AlphaFoldDB; P81744; -.
DR   SMR; P81744; -.
DR   ArachnoServer; AS000179; omega-agatoxin-Aa3b.
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.
DR   InterPro; IPR005853; Omega-agatoxin_II/III_CS.
DR   InterPro; IPR013605; Toxin_34.
DR   Pfam; PF08396; Toxin_34; 1.
DR   PROSITE; PS60023; OMEGA_AGA_II_III; 1.
PE   1: Evidence at protein level;
KW   Calcium channel impairing toxin; Direct protein sequencing; Disulfide bond;
KW   Ion channel impairing toxin; Knottin; Neurotoxin; Presynaptic neurotoxin;
KW   Secreted; Toxin; Voltage-gated calcium channel impairing toxin.
FT   CHAIN           1..76
FT                   /note="Omega-agatoxin-Aa3b"
FT                   /id="PRO_0000087607"
FT   DISULFID        2..19
FT                   /evidence="ECO:0000305"
FT   DISULFID        9..25
FT                   /evidence="ECO:0000305"
FT   DISULFID        16..52
FT                   /evidence="ECO:0000305"
FT   DISULFID        18..40
FT                   /evidence="ECO:0000305"
FT   DISULFID        27..38
FT                   /evidence="ECO:0000305"
FT   DISULFID        59..67
FT                   /evidence="ECO:0000305"
FT   VARIANT         29
FT                   /note="N -> S"
FT                   /evidence="ECO:0000269|PubMed:8172884"
FT   VARIANT         35
FT                   /note="K -> R"
FT                   /evidence="ECO:0000269|PubMed:8172884"
SQ   SEQUENCE   76 AA;  8620 MW;  D5C63C3AE8C95BB8 CRC64;
     SCIDFGGDCD GEKDDCQCCR SNGYCSCYNL FGYLKSGCKC EVGTSAEFRR ICRRKAKQCY
     NSDPDKCVSV YKPKRR