Control over multiple Nano- and Secondary Structures in Peptide Self-Assembly.
Herein, we report the unique morphological and conformational versatility of a biologically active peptide ( PEP-1 ), which undergoes diverse self-assembly pathways to form up to six distinct nanostructures and up to four different secondary structures through subtle modulations in pH, concentration and temperature. PEP-1 forms twisted β-sheet secondary structures and nanofibers at pH 7.4, which transform into fractal-like structures with strong β-sheet conformations at pH 13.0 or short disorganized elliptical aggregates at pH 5.5. Upon dilution at pH 7.4, the nanofibers with twisted β-sheet secondary structural elements convert into nanoparticles with random coil conformations. Interestingly, these two self-assembled states at pH 7.4 and room temperature are kinetically controlled and undergo a further transformation into thermodynamically stable states upon annealing: whereas the twisted β-sheet structures and corresponding nanofibers transform into 2D sheets with well-defined β-sheet domains, the nanoparticles with random coil structures convert into short nanorods with α-helix conformations. Notably, PEP-1 also showed high biocompatibility, low hemolytic activity and marked antibacterial activity, rendering our system a promising candidate for multiple bio-applications.
['Ghosh|Goutam|G|', 'Barman|Ranajit|R|', 'Mukherjee|Anurag|A|', 'Ghosh|Uttam|U|', 'Ghosh|Suhrit|S|', 'Fernandez|Gustavo|G|']
secondary structures nanostructures amphiphilic systems aqueous self-assembly pathway complexity