1P0S image
Entry Detail
PDB ID:
1P0S
Keywords:
Title:
Crystal Structure of Blood Coagulation Factor Xa in Complex with Ecotin M84R
Biological Source:
Source Organism:
Host Organism:
PDB Version:
Deposition Date:
2003-04-10
Release Date:
2003-08-26
Method Details:
Experimental Method:
Resolution:
2.80 Å
R-Value Free:
0.23
R-Value Work:
0.20
R-Value Observed:
0.20
Space Group:
I 2 2 2
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Ecotin precursor
Mutations:M84R
Chain IDs:C (auth: E)
Chain Length:142
Number of Molecules:1
Biological Source:Escherichia coli
Polymer Type:polypeptide(L)
Description:Coagulation factor X precursor
Chain IDs:B (auth: H)
Chain Length:254
Number of Molecules:1
Biological Source:Homo sapiens
Polymer Type:polypeptide(L)
Description:Coagulation factor X precursor
Chain IDs:A (auth: L)
Chain Length:138
Number of Molecules:1
Biological Source:Homo sapiens
Modified Residue
Compound ID Chain ID Parent Comp ID Details 2D Image
CGU A GLU GAMMA-CARBOXY-GLUTAMIC ACID
Primary Citation
The Extended Interactions and Gla Domain of Blood Coagulation Factor Xa
Biochemistry 42 7959 7966 (2003)
PMID: 12834348 DOI: 10.1021/bi027320a

Abstact

The serine protease factor Xa (FXa) is inhibited by ecotin with picomolar affinity. The structure of the tetrameric complex of ecotin variant M84R (M84R) with FXa has been determined to 2.8 A. Substrate directed induced fit of the binding interactions at the S2 and S4 pockets modulates the discrimination of the protease. Specifically, the Tyr at position 99 of FXa changes its conformation with respect to incoming ligand, changing the size of the S2 and S4 pockets. The role of residue 192 in substrate and inhibitor recognition is also examined. Gln 192 from FXa forms a hydrogen bond with the P2 carbonyl group of ecotin. This confirms previous biochemical and structural analyses on thrombin and activated protein C, which suggested that residue 192 may play a more general role in mediating the interactions between coagulation proteases and their inhibitors. The structure of ecotin M84R-FXa (M84R-FXa) also reveals the structure of the Gla domain in the presence of Mg(2+). The first 11 residues of the domain assume a novel conformation and likely represent an intermediate folding state of the domain.

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