Enrico Di Cera, M.D.
Alice A. Doisy Professor & Chair
Structural enzymology of coagulation factors.
Research Interests
Our research builds upon 30+ years of continuously funded work on the enzymology and structural biology of proteins involved in blood coagulation and on mechanisms of ligand binding.
We are interested in the structural enzymology of proteins responsible for blood coagulation, with the goal of unraveling their molecular architecture and mechanisms. Our approach uses a combination of conventional (rapid kinetics, protein engineering, X-ray crystallography) and innovative (smFRET, cryo-EM) biophysical techniques.
We currently focus on the structure, function and regulation of prothrombin (HL049413), protein C (HL139554) and factor V (HL147821). Also of interest is the molecular basis of protease specificity.
Research Highlights
Cryo-EM structures of human coagulation factors V and Va. Ruben EA, Rau MJ, Fitzpatrick JAJ, Di Cera E. Blood 137(22):3137, 2021.
Cryo-EM structure of the prothrombin-prothrombinase complex. Ruben EA, Summers B, Rau MJ, Fitzpatrick JAJ, Di Cera E. Blood 139(24):3463, 2022.
Recent Publications
Replacement of a single residue changes the primary specificity of thrombin
Replacement of a single residue changes the primary specificity of thrombin
Thrombin prefers substrates carrying Arg at the site of cleavage (P1) because of the presence of D189 in the primary specificity (S1) pocket but can also cleave substrates carrying Phe at P1. The structural basis of this property is unknown.
Another cryo-EM success: structure of FXIII
Conformation of factor Xa in solution revealed by single-molecule spectroscopy
Conformation of factor Xa in solution revealed by single-molecule spectroscopy
All current X-ray structures of factor (F)Xa are devoid of the γ-carboxyglutamate (Gla) domain and fail to reveal the overall conformation of the free protein. The recent cryogenic electron microscopy (cryo-EM) structure of FXa in the prothrombinase complex is the only structure of full-length FXa and shows that the Gla domain is positioned at an angle relative to the epidermal growth factor 1 domain.
Safety and tolerability of the protein C activator AB002 in end-stage renal disease patients on hemodialysis: a randomized phase 2 trial
Safety and tolerability of the protein C activator AB002 in end-stage renal disease patients on hemodialysis: a randomized phase 2 trial
The protein C system regulates blood coagulation, inflammation, and vascular integrity. AB002 is an injectable protein C activating enzyme under investigation to safely prevent and treat thrombosis. In preclinical models, AB002 is antithrombotic, cytoprotective, and anti-inflammatory. Since prophylactic use of heparin is contraindicated during hemodialysis in some end-stage renal disease (ESRD) patients, we propose using AB002 as a short-acting alternative to safely limit blood loss due to clotting in the dialysis circuit.
The Prothrombin-Prothrombinase Interaction
The Prothrombin-Prothrombinase Interaction
The hemostatic response to vascular injury entails a sequence of proteolytic events where several inactive zymogens of the trypsin family are converted to active proteases. The cascade starts with exposure of tissue factor from the damaged endothelium and culminates with conversion of prothrombin to thrombin in a reaction catalyzed by the prothrombinase complex composed of the enzyme factor Xa, cofactor Va, Ca, and phospholipids. This cofactor-dependent activation is paradigmatic of analogous reactions of the blood coagulation and complement cascades, which makes elucidation of its molecular mechanism of broad significance to the large class of trypsin-like zymogens to which prothrombin belongs. Because of its relevance as the most important reaction in the physiological response to vascular injury, as well as the main trigger of pathological thrombotic complications, the mechanism of prothrombin activation has been studied extensively. However, a molecular interpretation of this mechanism has become available only recently from important developments in structural biology. Here we review current knowledge on the prothrombin-prothrombinase interaction and outline future directions for the study of this key reaction of the coagulation cascade.
