In the parallel and anti-parallel β-sheet structures, hydrogen bonding arises between the amide bonds of the peptide chains to arrange them with a distance of ca. 5 Å. That distance matched with the repeating unit distance of polydiacetylene. In this study, the effectiveness of the β-sheet as a template for the polymerization of diacetylene was examined by using diacetylene-introduced oligopeptides. The diacetylene-introduced amino acid (Thr(DA)) was synthesized from L-threonine. Though peptides Ac-Thr(DA)-NHMe and Ac-[Thr(DA)]2-NHMe formed anti-parallel β-sheet, they showed slight or no polymerization in both of the solid and the solution states. On the other hand, Ac-[Thr(DA)]5-NHMe and 11mer peptide with a Thr(DA) in the center of the sequence contained anti-parallel β-sheet structure and formed polydiacetylene of high degree of polymerization with high conversion during the cleavage process of the peptide from resin in the solution. This result indicated that the preorganization of the peptide through the β-sheet formation was necessary for the polymerization of diacetylene group. Thus, the β-sheet motif was effective template for the polymerization of diacetylene.
All Science Journal Classification (ASJC) codes
- Statistical and Nonlinear Physics
- Condensed Matter Physics