Design of Achiral Peptides with a Terminal Functional Group and Their Helicity Induction

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The noncovalent chiral domino effect (NCDE) was proposed here as novel chiral interaction operating on a helical peptide. According to the NCDE principle, an optically inactive helical peptide undergoes chiral recognition at the N-terminus. Subsequently, the chiral signal acquired therein transfers to the C-terminus along the single chain, as if it is "domino toppling", finally leading to induction of excess of a one-handed helix. The results of the present project are summarized as follows.(1) Design of peptide backbone : An optically inactive peptide helix composed of non-coded residues was designed, and the solid-sate structure was investigated. This type of peptides shows a strong tendency to adopt a typical 3_<10>-helix.(2) Induction of helicity through NCDE : An N-terminal-free peptide, derived from (1), undergoes the induction of a one-handed helix through addition of chiral acid.(3) Control of helical structure of chiral peptide : NCDE was shown to enable control of the origina … More l helicity and helical stability of chiral peptides.(4) Stereochemistry for generating the NCDE : According to proposed mechanism of the NCDE, the N-terminal segment of a 3_<10>-helix possesses intrinsically two free amide NHs that tend to capture an external molecule through multipoint interaction to recognize the chirality.(5) Helicity induction through covalent chiral interaction : A screw sense preference of each amino acid residue was proposed from the relationship between a chiral sequence and the resulting helicity.(6) Conformational analysis of dehydropeptides having functional groups : These results open up the way to design a chiral functional device based on peptides.(7) Chiral induction in water through multi-D domino effect : A micelle composed of an optically inactive peptide underwent chiral induction, which also generates a highly asymmetrical space between peptide molecules. This finding in future might lead to the fabrication of novel chiral functional devices based on achiral peptide scaffold.In conclusion, the achievement of this project is of academic as well as of practical important in a wide range of polymer and chemistry fields. Less