ID   TX21_HADIN              Reviewed;          74 AA.
AC   A0A452CSQ9;
DT   11-DEC-2019, integrated into UniProtKB/Swiss-Prot.
DT   08-MAY-2019, sequence version 1.
DT   25-MAY-2022, entry version 12.
DE   RecName: Full=U21-hexatoxin-Hi1a {ECO:0000312|PDB:6BA3};
DE            Short=U21-HXTX-Hi1a {ECO:0000305};
OS   Hadronyche infensa (Fraser island funnel-web spider) (Atrax infensus).
OC   Eukaryota; Metazoa; Ecdysozoa; Arthropoda; Chelicerata; Arachnida; Araneae;
OC   Mygalomorphae; Hexathelidae; Hadronyche.
OX   NCBI_TaxID=153481;
RN   [1]
RP   STRUCTURE BY NMR, AND DISULFIDE BOND.
RA   Pineda S.S., Chin Y.K.-Y., Senff S., Mobli M., Escoubas P., Nicholson G.,
RA   Kass Q., Fry B.G., Mattick J.S., King G.F.;
RT   "Single-gene recruitment underlies venom complexity in the Australian
RT   funnel-web spider Hadronyche infensa.";
RL   Submitted (OCT-2017) to the PDB data bank.
CC   -!- FUNCTION: Probable neurotoxin with ion channel impairing activity.
CC       {ECO:0000305}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000305}.
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. {ECO:0000269|Ref.1}.
CC   -!- SIMILARITY: Belongs to the neurotoxin 21 family. {ECO:0000305}.
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DR   PDB; 6BA3; NMR; -; A=1-74.
DR   PDBsum; 6BA3; -.
DR   AlphaFoldDB; A0A452CSQ9; -.
DR   BMRB; A0A452CSQ9; -.
DR   SMR; A0A452CSQ9; -.
DR   GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR   GO; GO:0099106; F:ion channel regulator activity; IEA:UniProtKB-KW.
DR   GO; GO:0090729; F:toxin activity; IEA:UniProtKB-KW.
DR   InterPro; IPR035311; Cys_Knot_tox.
DR   Pfam; PF17486; Cys_Knot_tox; 1.
PE   1: Evidence at protein level;
KW   3D-structure; Disulfide bond; Ion channel impairing toxin; Knottin;
KW   Neurotoxin; Secreted; Toxin.
FT   CHAIN           1..74
FT                   /note="U21-hexatoxin-Hi1a"
FT                   /id="PRO_0000448638"
FT   DISULFID        23..37
FT                   /evidence="ECO:0000269|Ref.1, ECO:0007744|PDB:6BA3"
FT   DISULFID        30..49
FT                   /evidence="ECO:0000269|Ref.1, ECO:0007744|PDB:6BA3"
FT   DISULFID        36..64
FT                   /evidence="ECO:0000269|Ref.1, ECO:0007744|PDB:6BA3"
FT   DISULFID        67..74
FT                   /evidence="ECO:0000269|Ref.1, ECO:0007744|PDB:6BA3"
FT   HELIX           3..6
FT                   /evidence="ECO:0007829|PDB:6BA3"
FT   STRAND          20..22
FT                   /evidence="ECO:0007829|PDB:6BA3"
FT   HELIX           33..35
FT                   /evidence="ECO:0007829|PDB:6BA3"
FT   TURN            40..44
FT                   /evidence="ECO:0007829|PDB:6BA3"
FT   STRAND          45..52
FT                   /evidence="ECO:0007829|PDB:6BA3"
FT   TURN            55..58
FT                   /evidence="ECO:0007829|PDB:6BA3"
FT   STRAND          61..70
FT                   /evidence="ECO:0007829|PDB:6BA3"
SQ   SEQUENCE   74 AA;  8187 MW;  D25866A3C371EBBD CRC64;
     SNRWNLGYGI PHKQVKLPNG QLCKEPGDSC SKRDECCKAD DQKTYSSGCA QTWSAMEGGF
     VRECYICAVE SSMC