ID   3SOKA_HEMHA             Reviewed;          57 AA.
AC   P0DQH2;
DT   05-JUN-2019, integrated into UniProtKB/Swiss-Prot.
DT   05-JUN-2019, sequence version 1.
DT   25-MAY-2022, entry version 8.
DE   RecName: Full=Exactin {ECO:0000303|PubMed:27558950};
DE   AltName: Full=Extrinsic tenase-mediated FX activation inhibitor {ECO:0000303|PubMed:27558950};
OS   Hemachatus haemachatus (Rinkhals) (Sepedon haemachatus).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi;
OC   Lepidosauria; Squamata; Bifurcata; Unidentata; Episquamata; Toxicofera;
OC   Serpentes; Colubroidea; Elapidae; Elapinae; Hemachatus.
OX   NCBI_TaxID=8626;
RN   [1]
RP   PROTEIN SEQUENCE, SUBCELLULAR LOCATION, FUNCTION, AND MASS SPECTROMETRY.
RC   TISSUE=Venom;
RX   PubMed=27558950; DOI=10.1038/srep32036;
RA   Girish V.M., Kini R.M.;
RT   "Exactin: a specific inhibitor of Factor X activation by extrinsic tenase
RT   complex from the venom of Hemachatus haemachatus.";
RL   Sci. Rep. 6:32036-32036(2016).
CC   -!- FUNCTION: Anticoagulant protein that prevents the activation of factor
CC       X (F10). It acts by potently inhibiting the extrinsic tenase complex
CC       (ETC) (IC(50)=116.49 nM), a complex composed by active factor VII
CC       (F7a), tissue factor (TF) and F10. In addition, it shows weaker
CC       activities on other complexes. It weakly inhibits F10 activation by
CC       inhibiting the intrinsic tenase complex (IC(50)=4.05 uM), a complex
CC       composed by active factor IX (IXa, F9a), its cofactor factor VIII
CC       (VIIIa, F8a), and their substrate F10. It also weakly prevents
CC       prothrombin activation by inhibiting the prothrombinase complex
CC       (IC(50)=17.66 uM). It shows high kinetic constant towards
CC       F7a/TF/F10/phospholipids complex (Ki=30.62 nM) and lower kinetic
CC       constant towards F7a/TF/phospholipids complex (Ki=153.75 nM).
CC       {ECO:0000269|PubMed:27558950}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000269|PubMed:27558950}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC       {ECO:0000305|PubMed:27558950}.
CC   -!- MASS SPECTROMETRY: Mass=6621.12; Mass_error=0.22; Method=Electrospray;
CC       Evidence={ECO:0000269|PubMed:27558950};
CC   -!- MISCELLANEOUS: This protein does not show activity on procoagulant,
CC       anticoagulant and fibrinolytic serine proteases such as FVIIa, FXa,
CC       FIXa, FXIa, FXIIa, alpha-thrombin, kallikrein, activated protein C
CC       (APC), plasmin, urokinase, and tissue plasminogen activator
CC       (PubMed:27558950). Does not induce hemolysis (PubMed:27558950).
CC       {ECO:0000269|PubMed:27558950}.
CC   -!- MISCELLANEOUS: Is classified as a P-type cytotoxin, since a proline
CC       residue stands at position 28 (Pro-31 in standard classification).
CC       {ECO:0000305}.
CC   -!- SIMILARITY: Belongs to the snake three-finger toxin family. Short-chain
CC       subfamily. Orphan group XX sub-subfamily. {ECO:0000305}.
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DR   AlphaFoldDB; P0DQH2; -.
DR   SMR; P0DQH2; -.
DR   GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR   GO; GO:0090729; F:toxin activity; IEA:UniProtKB-KW.
DR   Gene3D; 2.10.60.10; -; 1.
DR   InterPro; IPR045860; Snake_toxin-like_sf.
DR   SUPFAM; SSF57302; SSF57302; 1.
PE   1: Evidence at protein level;
KW   Blood coagulation cascade inhibiting toxin; Direct protein sequencing;
KW   Disulfide bond; Hemostasis impairing toxin; Secreted; Toxin.
FT   CHAIN           1..57
FT                   /note="Exactin"
FT                   /evidence="ECO:0000269|PubMed:27558950"
FT                   /id="PRO_0000447299"
FT   DISULFID        3..19
FT                   /evidence="ECO:0000250|UniProtKB:P60301"
FT   DISULFID        12..37
FT                   /evidence="ECO:0000250|UniProtKB:P60301"
FT   DISULFID        41..49
FT                   /evidence="ECO:0000250|UniProtKB:P60301"
FT   DISULFID        50..55
FT                   /evidence="ECO:0000250|UniProtKB:P60301"
SQ   SEQUENCE   57 AA;  6630 MW;  7EC43442F6CF2F65 CRC64;
     LECYQKSKVV TCQPEQKFCY SDTTMFFPNH PVYLSGCTFS CTEEGNRRCC TTDKCNR