Synthesis and conformation of sequential polypeptides containing Îµ-benzyloxycarbonyl-iysine and benzyl esters of aspartic and glutamic acids
Sequential polypeptides with the repeating units NÎµ-Z-L-Lys-γ-Bzl-L-Glu and NÎµ-Z-L-Lys-β-Bzl-L-Asp have been synthesized by solution polymerization of their respective succinimido-esters. Both polypeptides are helical in solution in hexafluoropropan-2-ol and in trifluoroethanol, but random in hexafluoroacetone sesquihydrate, as shown by circular dichroism. Polarized i.r. spectra of oriented films of the polypeptides are also characteristic of the α-helical conformation.