Stabilization of the E* form turns thrombin into an anticoagulant.

Abstract

Previous studies have shown that deletion of nine residues in the autolysis loop of thrombin produces a mutant with an anticoagulant propensity of potential clinical relevance, but the molecular origin of the effect has remained unresolved. The x-ray crystal structure of this mutant solved in the free form at 1.55 A resolution reveals an inactive conformation that is practically identical (root mean square deviation of 0.154 A) to the recently identified E* form. The side chain of Trp(215) collapses into the active site by shifting > 10 A from its position in the active E form, and the oxyanion hole is disrupted by a flip of the Glu(192)-Gly(193) peptide bond. This finding confirms the existence of the inactive form E* in essentially the same incarnation as first identified in the structure of the thrombin mutant D102N. In addition, it demonstrates that the anticoagulant profile often caused by a mutation of the thrombin scaffold finds its likely molecular origin in the stabilization of the inactive E* form that is selectively shifted to the active E form upon thrombomodulin and protein C binding.

• Authors: Alaji Bah, Christopher J Carrell, Zhiwei Chen, Prafull S Gandhi, Enrico Di Cera
• Journal: The Journal of biological chemistry (J Biol Chem) Vol. 284 Issue 30 Pg. 20034-40 (Jul 24 2009) ISSN: 0021-9258 [Print] United States
• PMID: 19473969 (Publication Type: Journal Article, Research Support, N.I.H., Extramural)

Chemical References

• Anticoagulants
• Mutant Proteins
• Pipecolic Acids
• Protein C
• Sulfonamides
• Thrombomodulin
• Arginine
• Thrombin
• argatroban

Topics

• Anticoagulants (chemistry, metabolism)
• Arginine (analogs & derivatives)
• Binding Sites
• Crystallography, X-Ray
• Enzyme Activation
• Humans
• Models, Molecular
• Mutagenesis, Site-Directed
• Mutant Proteins (chemistry, genetics, metabolism)
• Pipecolic Acids (metabolism)
• Protein Binding
• Protein C (metabolism)
• Protein Conformation
• Sulfonamides
• Thrombin (chemistry, genetics, metabolism)
• Thrombomodulin (metabolism)