Design of a hyperstable 60-subunit protein icosahedron
Open Access
- 15 June 2016
- journal article
- research article
- Published by Springer Science and Business Media LLC in Nature
- Vol. 535 (7610), 136-139
- https://doi.org/10.1038/nature18010
Abstract
The computational design of an extremely stable icosahedral self-assembling protein nanocage is presented; the icosahedron should be useful for applications ranging from calibrating fluorescence microscopy to drug delivery. Icosahedral protein structures are widely utilized in biological systems for packaging and transport, and icosahedral viruses such as adenoviruses have been widely repurposed as vectors to package vaccines and for targeted delivery of therapeutics. Here David Baker and colleagues use computational design to produce icosahedral nanocage particles via self-assembly from trimeric building blocks. The particles are highly stable and robust to genetic fusions. The icosahedron is the largest of the Platonic solids, and icosahedral protein structures are widely used in biological systems for packaging and transport1,2. There has been considerable interest in repurposing such structures3,4,5 for applications ranging from targeted delivery to multivalent immunogen presentation. The ability to design proteins that self-assemble into precisely specified, highly ordered icosahedral structures would open the door to a new generation of protein containers with properties custom-tailored to specific applications. Here we describe the computational design of a 25-nanometre icosahedral nanocage that self-assembles from trimeric protein building blocks. The designed protein was produced in Escherichia coli, and found by electron microscopy to assemble into a homogenous population of icosahedral particles nearly identical to the design model. 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. 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 delivery6, vaccine design7 and synthetic biology8.Keywords
This publication has 42 references indexed in Scilit:
- Metal-Mediated Affinity and Orientation Specificity in a Computationally Designed Protein HomodimerJournal of the American Chemical Society, 2011
- Rosetta3Methods in Enzymology, 2010
- Channeling by Proximity: The Catalytic Advantages of Active Site Colocalization Using Brownian DynamicsThe Journal of Physical Chemistry Letters, 2010
- Nanoscale elongating control of the self‐assembled protein filament with the cysteine‐introduced building blocksProtein Science, 2009
- The Rough Energy Landscape of Superfolder GFP Is Linked to the ChromophoreJournal of Molecular Biology, 2007
- EMAN2: An extensible image processing suite for electron microscopyJournal of Structural Biology, 2007
- UCSF Chimera?A visualization system for exploratory research and analysisJournal of Computational Chemistry, 2004
- SPIDER and WEB: Processing and Visualization of Images in 3D Electron Microscopy and Related FieldsJournal of Structural Biology, 1996
- A New Generation of the IMAGIC Image Processing SystemJournal of Structural Biology, 1996
- Shape Complementarity at Protein/Protein InterfacesJournal of Molecular Biology, 1993