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Published on: June 25, 2017
A prourokinase-RGDS chimera : Construction, expression and characterization
1National Laboratory of Protein Engineering, Department of Biochemistry and Molecular Biology, Life Science Centre, Peking University, 100871, Beijing, China.
Science in China. Series C, Life Sciences
|March 16, 2010
Summary
A novel chimera incorporating the RGDS tetrapeptide into pro-urokinase (proUK) demonstrates effective calcium-dependent platelet binding and potent thrombolytic activity. This engineered protein shows comparable amidolytic and plasminogen activation to native urokinase, suggesting its potential as a bifunctional therapeutic agent.
Area of Science:
- Biochemistry
- Molecular Biology
- Biotechnology
Background:
- Urokinase (UK) is a serine protease involved in fibrinolysis.
- Developing effective thrombolytic agents with improved targeting and dual functionality is crucial for treating thrombotic diseases.
- The RGDS tetrapeptide sequence is known to interact with integrins on platelet surfaces.
Purpose of the Study:
- To engineer a recombinant pro-urokinase (proUK) chimera containing the RGDS tetrapeptide within its kringle domain.
- To characterize the biochemical and functional properties of the proUK-RGDS chimera.
- To evaluate the potential of the chimera as a bifunctional thrombolytic agent.
Main Methods:
- Construction and expression of a mutant proUK-RGDS gene using the baculovirus system.
- Purification of the chimera via immunoaffinity chromatography.
- Assessment of calcium-dependent platelet membrane binding.
- Enzyme activity assays including amidolytic activity and plasminogen activation kinetics (Michaelis-Menten).
- In vitro platelet aggregation inhibition assays.
Main Results:
- The proUK-RGDS chimera was purified to >90% purity.
- The chimera exhibited calcium-dependent binding to platelet membranes.
- Specific amidolytic activity of plasmin-activated chimera (62,000 IU/mg) was comparable to native proUK.
- Plasminogen activation by the chimera followed Michaelis-Menten kinetics with a Km of 0.97 µmol/L, similar to native urokinase.
- The chimera demonstrated significant inhibition of platelet aggregation in vitro.
Conclusions:
- The engineered proUK-RGDS chimera retains key functional properties of native urokinase, including enzymatic activity and plasminogen activation.
- The chimera's ability to bind to platelets and inhibit aggregation suggests enhanced targeting and a dual mechanism of action.
- This bifunctional chimera holds promise as a novel therapeutic agent for thrombolysis.
