ProteinCProteinSWeg

ProteinCProteinSWeg is a fictional fusion protein introduced as an illustrative example of coagulation factor engineering. It is described as a single polypeptide that combines elements of human Protein C and Protein S to explore how proteolytic activity and membrane targeting might be integrated in a synthetic anticoagulant model.

Design and architecture

The proposed construct merges the catalytic serine protease domain of Protein C with regions derived from Protein S intended to provide calcium-dependent phospholipid binding. A flexible linker connects the domains to allow correct folding and domain autonomy. In the schematic model, the N-terminal portion includes a surface-facing Gla domain and EGF-like repeats associated with Protein S, while the C-terminal portion contains the active protease domain responsible for substrate recognition and cleavage.

Expression and biochemical properties

In silico designs predict that the fusion protein would be expressed as a secreted glycoprotein when produced in mammalian systems, retaining typical post-translational modifications such as N-linked glycosylation. Biochemical assays would assess calcium dependence, phospholipid vesicle binding, and proteolytic activity against synthetic substrates that mimic natural substrates (for example, factors Va and VIIIa–derived sequences). Purification would likely use affinity techniques compatible with secreted, glycosylated proteins.

Function and potential applications

As a research tool, ProteinCProteinSWeg is used to study the cooperative interactions between Protein C and Protein S and to model how cofactor surfaces influence proteolysis on phospholipid membranes. It has potential applications in in vitro coagulation assays and high-throughput screens for modulators of anticoagulant activity. Its therapeutic value remains speculative; there are considerations about immunogenicity, bleeding risk, and regulatory hurdles in translating a synthetic fusion protein to clinical use.

See also

Protein C; Protein S; coagulation system.