title: Conversion of a monodispersed globular protein into an amyloid-like filament by appending an artificial peptide at the N-terminal.
abstract: The soluble, globular, alpha-helix-rich peptide SipA(446-684) is a domain of a bacterial protein that binds to mammalian filamentous-actin and re-arranges the host cell's cytoskeleton. We show that adding two copies of NHBP-1, a carbon nanomaterial binding peptide, to its N-terminal can induce SipA(446-684) to polymerize and assume a fibrillar structure under physiological conditions. The fibrils formed showed thioflavine T and Congo red staining profiles that are characteristic of and specific for amyloid-like structures. The alpha-helical structure of the globular protein was retained in the fibrils, suggesting the appended NHBP-1 sequence plays a key role in the formation of cross-beta spines within the fibrils. Consistent with that idea, we observed that a synthetic NHBP-1 peptide can form an amyloid-like structure under appropriate conditions. Thus, our findings add a new subtype of amyloid-like structure formation and suggest this method of assembly could be exploited in nano-biotechnology.
authors.affiliation: Department of Protein Engineering, Cancer Institute, Japanese Foundation for Cancer Research and CREST, JST, Koto-Ku, Tokyo 135-8550 Japan.
authors.forename: Ken-Ichi
authors.initials: K
authors.lastname: Sano
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Sasaki
authors.forename: Kiyotaka
authors.initials: K
authors.lastname: Shiba
mesh_terms: D000682:Amyloid / Q000737:chemistry*; D001426:Bacterial Proteins / Q000737:chemistry*; D008840:Microfilament Proteins / Q000737:chemistry*; D010455:Peptides / Q000737:chemistry*; D012486:Salmonella typhimurium
chemical_list: D000682:Amyloid; D001426:Bacterial Proteins; D008840:Microfilament Proteins; D010455:Peptides; C118287:SipA protein, Salmonella