A designed β-hairpin forming peptide undergoes a consecutive stepwise process for self-assembly into nanofibrils

We used a de novo designed,β-hairpin forming t1 peptide as a model to investigate the kinetics of peptide fibrogenesis by a combination of light scattering (ls),circular dichroism (cd),fluorescence,and atomic force microscopy (afm). the results demonstrate that the t1 fibrogenesis undergoes a consecutive stepwise process,with a high degree of cooperation,presenting sigmoidal time-courses of the peptide aggregation,the subsequent conformational conversion of the backbone,and the peptide sidechains' rearrangement. we suggest that the conformational conversion was initiated after the peptide aggregates reach a dimensional size threshold,which could be a key step in the formation of β-structural nuclei that catalyze the subsequent reactions. furthermore,besides triggering the peptide aggregation,the interactions between the peptide sidechains predominately facilitate the regular alignment of the peptide molecules and the formation of a well-defined suprastructure. this work provides an insight of the hierarchical self-assembly of β-hairpin forming peptides. it is helpful for designing β-structural peptides for self-assembly into nanowires,which would have potential applications in the construction of nano-materials. © 2010 bentham science publishers ltd.