Comparative sequence analysis of vitamin K-dependent coagulation factors

Area of Science:

• Evolutionary biology
• Biochemistry
• Hematology

Background:

• Vitamin K-dependent proteins (prothrombin, protein C, factors VII, IX, X) regulate blood coagulation.
• Coagulation evolved from immune and developmental enzyme cascades in vertebrates.
• Evolutionary changes and residue conservation in these proteins are poorly understood.

Purpose of the Study:

• To analyze the conservation of functionally critical residues in vitamin K-dependent coagulation proteins across vertebrate lineages.
• To understand evolutionary modifications in these proteins, particularly concerning zymogen activation and catalysis.

Main Methods:

• Analysis of over 1600 primary sequences of vitamin K-dependent proteins.
• Focus on residues essential for zymogen activation and catalytic activity.

Main Results:

• Residue conservation varies, with prothrombin showing the highest and protein C the lowest.
• Significant functional changes in protein C occurred in bony fish ancestors (activation site residue change).
• Protein C evolved additional disulfide bonds and altered cleavage sites during placental mammal radiation.

Conclusions:

• Variations in functionally important residues contribute to interspecies differences in vitamin K-dependent protein function.
• These sequence differences influence zymogen activation and catalytic properties.
• Understanding these evolutionary changes is key to comprehending coagulation diversity.