One impressive ability of certain viruses is how they use protein shells to transport their genomes safely through a living organism, releasing the undamaged cargo just where needed. Researchers at the University of Washington have now developed a protein icosahedron modeled on the virus shells, to transport man-made cargo into individual cells within the body. The research bodes well for the development of an entire field of artificial protein modeling which may lead to the creation of a wide variety of molecular tools and vehicles for clinical applications.
The icosahedral protein nano-cage was originally created in a computer simulation, and a laboratory experiment within E. coli led to the genesis of the actual vesicle from biochemical components and DNA strands that provided the data for its construction. The self-assembled cage was then analyzed using a microscope to confirm that it closely matched the design developed on the computer.
The researchers published their findings in journal Nature where they point to the impressively stable nature of the new shell: “The particles are stable in 6.7 molar guanidine hydrochloride at up to 80 degrees Celsius, and undergo extremely abrupt, but reversible, disassembly between 2 molar and 2.25 molar guanidinium thiocyanate.”
Some more details from the abstract in Nature:
The icosahedron is robust to genetic fusions: one or two copies of green fluorescent protein (GFP) can be fused to each of the 60 subunits to create highly fluorescent ‘standard candles’ for use in light microscopy, and a designed protein pentamer can be placed in the centre of each of the 20 pentameric faces to modulate the size of the entrance/exit channels of the cage. Such robust and customizable nanocages should have considerable utility in targeted drug delivery, vaccine design and synthetic biology.
Study in Nature: Design of a hyperstable 60-subunit protein icosahedron