3ELA

Crystal structure of active site inhibited coagulation factor VIIA mutant in complex with soluble tissue factor

Summary for 3ELA

• Entry DOI: 10.2210/pdb3ela/pdb
• Related PRD ID: PRD_000369
• Descriptor: Coagulation factor VIIA light chain, Coagulation factor VIIA heavy chain, Tissue factor, ... (8 entities in total)
• Functional Keywords: serine protease, blood clotting, hydrolase-hydrolase inhibitor complex, hydrolase/hydrolase inhibitor
• Biological source: Homo sapiens (human); More
• Total number of polymer chains: 3
• Total formula weight: 69653.77

Authors

Bjelke, J.R.,Fodje, M.,Svensson, L.A. (deposition date: 2008-09-21, release date: 2008-11-04, Last modification date: 2024-10-30)

Primary citation

Bjelke, J.R.,Olsen, O.H.,Fodje, M.,Svensson, L.A.,Bang, S.,Bolt, G.,Kragelund, B.B.,Persson, E.
Mechanism of the Ca2+-induced enhancement of the intrinsic factor VIIa activity
J.Biol.Chem., 283:25863-25870, 2008

PubMed Abstract: The intrinsic activity of coagulation factor VIIa (FVIIa) is dependent on Ca(2+) binding to a loop (residues 210-220) in the protease domain. Structural analysis revealed that Ca(2+) may enhance the activity by attenuating electrostatic repulsion of Glu(296) and/or by facilitating interactions between the loop and Lys(161) in the N-terminal tail. In support of the first mechanism, the mutations E296V and D212N resulted in similar, about 2-fold, enhancements of the amidolytic activity. Moreover, mutation of the Lys(161)-interactive residue Asp(217) or Asp(219) to Ala reduced the amidolytic activity by 40-50%, whereas the K161A mutation resulted in 80% reduction. Hence one of these Asp residues in the Ca(2+)-binding loop appears to suffice for some residual interaction with Lys(161), whereas the more severe effect upon replacement of Lys(161) is due to abrogation of the interaction with the N-terminal tail. However, Ca(2+) attenuation of the repulsion between Asp(212) and Glu(296) keeps the activity above that of apoFVIIa. Altogether, our data suggest that repulsion involving Asp(212) in the Ca(2+)-binding loop suppresses FVIIa activity and that optimal activity requires a favorable interaction between the Ca(2+)-binding loop and the N-terminal tail. Crystal structures of tissue factor-bound FVIIa(D212N) and FVIIa(V158D/E296V/M298Q) revealed altered hydrogen bond networks, resembling those in factor Xa and thrombin, after introduction of the D212N and E296V mutations plausibly responsible for tethering the N-terminal tail to the activation domain. The charge repulsion between the Ca(2+)-binding loop and the activation domain appeared to be either relieved by charge removal and new hydrogen bonds (D212N) or abolished (E296V). We propose that Ca(2+) stimulates the intrinsic FVIIa activity by a combination of charge neutralization and loop stabilization.

PubMed: 18640965
DOI: 10.1074/jbc.M800841200

Experimental method

X-RAY DIFFRACTION (2.2 Å)