ID   TXLB1_CYRSC             Reviewed;          83 AA.
AC   B3FIS6;
DT   28-JUL-2009, integrated into UniProtKB/Swiss-Prot.
DT   22-JUL-2008, sequence version 1.
DT   25-MAY-2022, entry version 37.
DE   RecName: Full=U5-theraphotoxin-Hs1b 1 {ECO:0000305};
DE            Short=U5-TRTX-Hs1b {ECO:0000305};
DE   AltName: Full=Lectin SHL-Ib1 {ECO:0000303|PubMed:18482741};
DE   Flags: Precursor;
OS   Cyriopagopus schmidti (Chinese bird spider) (Haplopelma schmidti).
OC   Eukaryota; Metazoa; Ecdysozoa; Arthropoda; Chelicerata; Arachnida; Araneae;
OC   Mygalomorphae; Theraphosidae; Cyriopagopus.
OX   NCBI_TaxID=29017;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA].
RC   TISSUE=Venom gland;
RX   PubMed=18482741; DOI=10.1016/j.toxicon.2008.03.024;
RA   Jiang L., Peng L., Chen J., Zhang Y., Xiong X., Liang S.;
RT   "Molecular diversification based on analysis of expressed sequence tags
RT   from the venom glands of the Chinese bird spider Ornithoctonus huwena.";
RL   Toxicon 51:1479-1489(2008).
RN   [2]
RP   X-RAY CRYSTALLOGRAPHY (1.89 ANGSTROMS) OF 50-81, FUNCTION, SYNTHESIS OF
RP   50-81, AND DISULFIDE BONDS.
RX   PubMed=29483648; DOI=10.1038/s41594-018-0033-9;
RA   Correnti C.E., Gewe M.M., Mehlin C., Bandaranayake A.D., Johnsen W.A.,
RA   Rupert P.B., Brusniak M.Y., Clarke M., Burke S.E., De Van Der Schueren W.,
RA   Pilat K., Turnbaugh S.M., May D., Watson A., Chan M.K., Bahl C.D.,
RA   Olson J.M., Strong R.K.;
RT   "Screening, large-scale production and structure-based classification of
RT   cystine-dense peptides.";
RL   Nat. Struct. Mol. Biol. 25:270-278(2018).
CC   -!- FUNCTION: Weakly inhibits 5HT3A receptors and Kv1.3/KCNA3 voltage-gated
CC       potassium channels (PubMed:29483648). Agglutinates erythrocytes (By
CC       similarity). {ECO:0000250|UniProtKB:Q86C51,
CC       ECO:0000269|PubMed:29483648}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000305|PubMed:18482741}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC       {ECO:0000305|PubMed:18482741}.
CC   -!- DOMAIN: The presence of a 'disulfide through disulfide knot'
CC       structurally defines this protein as a knottin.
CC   -!- SIMILARITY: Belongs to the neurotoxin 10 (Hwtx-1) family. 51 (Hntx-8)
CC       subfamily. Hntx-8 sub-subfamily. {ECO:0000305}.
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DR   EMBL; EU195270; ABY77723.1; -; mRNA.
DR   PDB; 6AV8; X-ray; 1.89 A; A=50-82.
DR   PDBsum; 6AV8; -.
DR   AlphaFoldDB; B3FIS6; -.
DR   SMR; B3FIS6; -.
DR   ArachnoServer; AS000698; U5-theraphotoxin-Hs1b.
DR   GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR   GO; GO:0030246; F:carbohydrate binding; IEA:UniProtKB-KW.
DR   GO; GO:0008200; F:ion channel inhibitor activity; IEA:InterPro.
DR   GO; GO:0015459; F:potassium channel regulator activity; IEA:UniProtKB-KW.
DR   GO; GO:0090729; F:toxin activity; IEA:UniProtKB-KW.
DR   InterPro; IPR011696; Huwentoxin-1.
DR   Pfam; PF07740; Toxin_12; 1.
PE   1: Evidence at protein level;
KW   3D-structure; Cleavage on pair of basic residues; Disulfide bond;
KW   Ion channel impairing toxin; Knottin; Lectin;
KW   Potassium channel impairing toxin; Secreted; Signal; Toxin;
KW   Voltage-gated potassium channel impairing toxin.
FT   SIGNAL          1..21
FT                   /evidence="ECO:0000255"
FT   PROPEP          22..49
FT                   /evidence="ECO:0000305"
FT                   /id="PRO_0000380174"
FT   CHAIN           50..81
FT                   /note="U5-theraphotoxin-Hs1b 1"
FT                   /evidence="ECO:0000305"
FT                   /id="PRO_0000380175"
FT   DISULFID        51..63
FT                   /evidence="ECO:0000312|PDB:6AV8"
FT   DISULFID        56..68
FT                   /evidence="ECO:0000312|PDB:6AV8"
FT   DISULFID        62..75
FT                   /evidence="ECO:0000312|PDB:6AV8"
FT   STRAND          58..60
FT                   /evidence="ECO:0007829|PDB:6AV8"
FT   TURN            70..72
FT                   /evidence="ECO:0007829|PDB:6AV8"
FT   STRAND          73..76
FT                   /evidence="ECO:0007829|PDB:6AV8"
SQ   SEQUENCE   83 AA;  9477 MW;  987E1F556585190D CRC64;
     MKTSMFLTLT GLVLLFVVCY ASESEEKEFP KELLSSIFAA DSDFKEEERG CFGYKCDYYK
     GCCSGYVCSP TWKWCVRPGP GRR