PEDS Advance Access originally published online on February 9, 2007
Protein Engineering Design and Selection 2007 20(3):109-116; doi:10.1093/protein/gzm001
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Conversion of a monodispersed globular protein into an amyloid-like filament by appending an artificial peptide at the N-terminal
1 Department of Protein Engineering, Cancer Institute, Japanese Foundation for Cancer Research and CREST, JST, Koto-Ku, Tokyo 135-8550 Japan 2 Department of Molecular Cell Biology, Institute of DNA Medicine, The Jikei University School of Medicine, Japan
3 To whom correspondence should be addressed. E-mail: kshiba{at}jfcr.or.jp
The soluble, globular, 
-helix-rich peptide SipA446–684 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 SipA446–684 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 -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-ß 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.
Keywords: cross-ß structure/peptide aptamer/self-assembly, single wall carbon nanohorns/SipA
Received October 19, 2006; revised December 8, 2006; accepted December 24, 2006.