title: Engineering amyloid fibrils from β-solenoid proteins for biomaterials applications.
abstract: Nature provides numerous examples of self-assembly that can potentially be implemented for materials applications. Considerable attention has been given to one-dimensional cross-β or amyloid structures that can serve as templates for wire growth or strengthen materials such as glue or cement. Here, we demonstrate controlled amyloid self-assembly based on modifications of β-solenoid proteins. They occur naturally in several contexts (e.g., antifreeze proteins, drug resistance proteins) but do not aggregate in vivo due to capping structures or distortions at their ends. Removal of these capping structures and regularization of the ends of the spruce budworm and rye grass antifreeze proteins yield micron length amyloid fibrils with predictable heights, which can be a platform for biomaterial-based self-assembly. The design process, including all-atom molecular dynamics simulations, purification, and self-assembly procedures are described. Fibril formation with the predicted characteristics is supported by evidence from thioflavin-T fluorescence, circular dichroism, dynamic light scattering, and atomic force microscopy. Additionally, we find evidence for lateral assembly of the modified spruce budworm antifreeze fibrils with sufficient incubation time. The kinetics of polymerization are consistent with those for other amyloid formation reactions and are relatively fast due to the preformed nature of the polymerization nucleus.
authors.affiliation: Department of Chemistry, ‡Department of Physics, and §Institute for Complex Adaptive Matter, University of California , 1 Shields Avenue, Davis, California 95616, United States.
authors.forename: Maria D R
authors.initials: MD
authors.lastname: Peralta
authors.forename: Arpad
authors.initials: A
authors.lastname: Karsai
authors.forename: Alice
authors.initials: A
authors.lastname: Ngo
authors.forename: Catherine
authors.initials: C
authors.lastname: Sierra
authors.forename: Kai T
authors.initials: KT
authors.lastname: Fong
authors.forename: Natha Robert
authors.initials: NR
authors.lastname: Hayre
authors.forename: Nima
authors.initials: N
authors.lastname: Mirzaee
authors.forename: Krishnakumar Mayuram
authors.initials: KM
authors.lastname: Ravikumar
authors.forename: Alexander J
authors.initials: AJ
authors.lastname: Kluber
authors.forename: Xi
authors.initials: X
authors.lastname: Chen
authors.forename: Gang-yu
authors.initials: GY
authors.lastname: Liu
authors.forename: Michael D
authors.initials: MD
authors.lastname: Toney
authors.forename: Rajiv R
authors.initials: RR
authors.lastname: Singh
authors.forename: Daniel Lee
authors.initials: DL
authors.lastname: Cox
mesh_terms: D000595:Amino Acid Sequence; D000682:Amyloid / Q000737:chemistry* / Q000235:genetics; D000818:Animals; D021301:Antifreeze Proteins / Q000737:chemistry* / Q000235:genetics; D001672:Biocompatible Materials / Q000737:chemistry*; D019476:Insect Proteins / Q000737:chemistry* / Q000235:genetics; D007700:Kinetics; D007915:Lepidoptera; D056004:Molecular Dynamics Simulation; D008969:Molecular Sequence Data; D036103:Nanotechnology / Q000379:methods*; D015202:Protein Engineering / Q000379:methods*; D017510:Protein Folding; D017433:Protein Structure, Secondary
chemical_list: D000682:Amyloid; D021301:Antifreeze Proteins; D001672:Biocompatible Materials; D019476:Insect Proteins
keywords: amyloid; antifreeze protein; atomic force microscopy; thioflavin-T fluorescence; β-solenoid