Hierarchical self-assembly in diblock copolypeptides of poly(γ-benzyl-l-glutamate) with poly poly(l-leucine) and poly(O-benzyl-l-tyrosine)

Block copolypeptides with their inherent nanometer length scale of phase separation, provide means of manipulating the type (α-helices, β-strands) and persistence of peptide secondary structures. Two such examples are employed based on the α-helical poly(γ-benzyl-l- glutamate) (PBLG) polypeptide as one block and poly(l-leucine) (α-helical) or poly(O-benzyl-l-tyrosine) (POBT) (β-strands) as the second block. Although both secondary structures are present in the copolypeptides the effect of nano-scale confinement is to induce folding in the POBT β-sheets and to maintain the defected α-helices of PBLG and PLEU with a limited lateral coherence.