title: Accurate design of megadalton-scale two-component icosahedral protein complexes.
abstract: Nature provides many examples of self- and co-assembling protein-based molecular machines, including icosahedral protein cages that serve as scaffolds, enzymes, and compartments for essential biochemical reactions and icosahedral virus capsids, which encapsidate and protect viral genomes and mediate entry into host cells. Inspired by these natural materials, we report the computational design and experimental characterization of co-assembling, two-component, 120-subunit icosahedral protein nanostructures with molecular weights (1.8 to 2.8 megadaltons) and dimensions (24 to 40 nanometers in diameter) comparable to those of small viral capsids. Electron microscopy, small-angle x-ray scattering, and x-ray crystallography show that 10 designs spanning three distinct icosahedral architectures form materials closely matching the design models. In vitro assembly of icosahedral complexes from independently purified components occurs rapidly, at rates comparable to those of viral capsids, and enables controlled packaging of molecular cargo through charge complementarity. The ability to design megadalton-scale materials with atomic-level accuracy and controllable assembly opens the door to a new generation of genetically programmable protein-based molecular machines.
authors.affiliation: Department of Biochemistry, University of Washington, Seattle, WA 98195, USA. Graduate Program in Molecular and Cellular Biology, University of Washington, Seattle, WA 98195, USA.
authors.forename: Jacob B
authors.initials: JB
authors.lastname: Bale
authors.affiliation: Department of Biochemistry, University of Washington, Seattle, WA 98195, USA. Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA.
authors.forename: Shane
authors.initials: S
authors.lastname: Gonen
authors.affiliation: Department of Chemistry and Biochemistry, University of California-Los Angeles (UCLA), Los Angeles, CA 90095, USA.
authors.forename: Yuxi
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Biochemistry, University of Washington, Seattle, WA 98195, USA.
authors.forename: William
authors.initials: W
authors.lastname: Sheffler
authors.affiliation: Institute for Protein Design, University of Washington, Seattle, WA 98195, USA.
authors.forename: Daniel
authors.initials: D
authors.lastname: Ellis
authors.affiliation: Department of Chemistry, University of Washington, Seattle, WA 98195, USA.
authors.forename: Chantz
authors.initials: C
authors.lastname: Thomas
authors.affiliation: Department of Chemistry and Biochemistry, University of California-Los Angeles (UCLA), Los Angeles, CA 90095, USA. UCLA-Department of Energy (DOE) Institute for Genomics and Proteomics, Los Angeles, CA 90095, USA. Department of Biological Chemistry and Molecular Biology Institute, UCLA, Los Angeles, CA 90095, USA.
authors.forename: Duilio
authors.initials: D
authors.lastname: Cascio
authors.affiliation: Department of Chemistry and Biochemistry, University of California-Los Angeles (UCLA), Los Angeles, CA 90095, USA. UCLA-Department of Energy (DOE) Institute for Genomics and Proteomics, Los Angeles, CA 90095, USA.
authors.forename: Todd O
authors.initials: TO
authors.lastname: Yeates
authors.affiliation: Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA.
authors.forename: Tamir
authors.initials: T
authors.lastname: Gonen
authors.affiliation: Department of Biochemistry, University of Washington, Seattle, WA 98195, USA. Institute for Protein Design, University of Washington, Seattle, WA 98195, USA. neilking@uw.edu dabaker@uw.edu.
authors.forename: Neil P
authors.initials: NP
authors.lastname: King
authors.affiliation: Department of Biochemistry, University of Washington, Seattle, WA 98195, USA. Institute for Protein Design, University of Washington, Seattle, WA 98195, USA. Howard Hughes Medical Institute, University of Washington, Seattle, WA 98195, USA. neilking@uw.edu dabaker@uw.edu.
authors.forename: David
authors.initials: D
authors.lastname: Baker
mesh_terms: D002213:Capsid / Q000737:chemistry* / Q000648:ultrastructure; D018360:Crystallography, X-Ray; D016679:Genome, Viral; D008854:Microscopy, Electron; D008958:Models, Molecular; D008970:Molecular Weight; D046912:Multiprotein Complexes / Q000737:chemistry / Q000648:ultrastructure; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure; D015202:Protein Engineering / Q000379:methods*; D021122:Protein Subunits / Q000737:chemistry* / Q000235:genetics; D053838:Scattering, Small Angle; D014764:Viral Proteins / Q000737:chemistry* / Q000235:genetics / Q000648:ultrastructure; D014961:X-Ray Diffraction
chemical_list: D046912:Multiprotein Complexes; D021122:Protein Subunits; D014764:Viral Proteins