title: Hyperthin nanochains composed of self-polymerizing protein shackles.
abstract: Protein fibrils are expected to have applications as functional nanomaterials because of their sophisticated structures; however, nanoscale ordering of the functional units of protein fibrils remains challenging. Here we design a series of self-polymerizing protein monomers, referred to as protein shackles, derived from modified recombinant subunits of pili from Streptococcus pyogenes. The monomers polymerize into nanochains through spontaneous irreversible covalent bond formation. We design the protein shackles so that their reactions can be controlled by altering redox conditions, which affect disulphide bond formation between engineered cysteine residues. The interaction between the monomers improves their polymerization reactivity and determines morphologies of the polymers. In addition, green fluorescent protein-tagged protein shackles can polymerize, indicating proteins can be stably attached to the nanochains with its functionality preserved. Furthermore we demonstrate that a molecular-recognizable nanochain binds to its partner with an enhanced binding ability in solution. These characteristics are expected to be applied for novel protein nanomaterials.
authors.affiliation: The Medical Proteomics Laboratory, The Institute of Medical Science, The University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Matsunaga
authors.forename: Saeko
authors.initials: S
authors.lastname: Yanaka
authors.forename: Satoru
authors.initials: S
authors.lastname: Nagatoishi
authors.forename: Kouhei
authors.initials: K
authors.lastname: Tsumoto
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D003545:Cysteine / Q000737:chemistry; D010861:Fimbriae, Bacterial / Q000737:chemistry*; D049452:Green Fluorescent Proteins / Q000737:chemistry; D008422:Materials Testing; D008565:Membrane Proteins / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure; D010084:Oxidation-Reduction; D058105:Polymerization; D017510:Protein Folding; D013297:Streptococcus pyogenes / Q000737:chemistry; D013816:Thermodynamics
chemical_list: D001672:Biocompatible Materials; D008565:Membrane Proteins; D049452:Green Fluorescent Proteins; D003545:Cysteine