Synthesis of histone model sequences for immobilization on a cross-linked polyacrylate matrix

The synthesis of three peptide sequences which are useful as histone models, [Lys]5, [Lys]5-Pro and the sequence 17-27 of the lysine-rich histone from rabbit thymus Pro-Ala-Lys-Lys-Lys-Lys-Ala-Ala-Lys-Lys-Pro is described. Three different methods for the synthesis are applied. [Lys] 5 is synthesized from the amino end beginning with N alpha-acryloyl-N epsilon-Cbo-lysine by successive coupling of Cbo-lysine to yield the pentalysine monomer CH2=CH-CO-[Lys(Cbo)]5 which can be used directly for radical copolymerization. [Lys]5-Pro is synthesized according to the conventional peptide synthesis using the carbobenzoxy group for N alpha-protection and the tert,-butyl group for side chain protection. The carboxyl function is protected as tert.-butyl ester. The undecapeptide is synthesized in a similar manner. Instead of purifying the intermediate peptides by extraction, chromatography is used exclusively. The isolation of the unprotected peptides Lys-Pro, [Lys]3-Pro, [Lys]4-Pro, [Lys]5-Pro and Pro-Ala-[Lys]4-[Ala]2-[Lys]2-Pro and their characterization using amino acid analysis, electrophoreses and field desorption mass spectrometry is also reported.