Photo-Crosslinking Induced Geometric Restriction Controls the Self-Assembly of Diphenylalanine Based Peptides

The diphenylalanine(FF)motif has been widely used in the design of peptides that are capable of forming various ordered structures,such as nanotubes,nanospheres and hydrogels.In these assemblies,FF based peptides adopt an antiparallel structure and are stabilized by n-TT stacking among the phenyl groups.Here we show that assembly of FF-based peptides can be controlled by their geometric restrictions.Using tripeptide FFY(L-Phe-L-Phe-L-Tyr)as an example,we demonstrate that photo-crosslinking of C-terminal tyrosine can impose a geometric restriction to the formation of an antiparallel structure,leading to a structural change of the assemblies from nanosphere to amorphous.