SynopsisAlternating poly(Arg-Leu) and copolypeptides with Arg-Leu and His-Leu sequences were prepared by condensation of the corresponding p-nitrophenyl dipeptide esters in the presence of 1-hydroxybenzotriazole. Arginine was used without any protection and histidine side chains were protected using r-benzyloxymethyl group recently introduced in peptide chemistry. The ability of these polypeptides with alternating hydrophilic and hydrophobic residues to form water-soluble P-sheets was investigated by CD.