POLYPEPTIDE-SYNTHESIS USING THE S-ALKYL THIOESTER OF A PARTIALLY PROTECTED PEPTIDE SEGMENT - SYNTHESIS OF THE DNA-BINDING DOMAIN OF C-MYB PROTEIN (142-193)-NH2

A method for polypeptide synthesis using S-alkyl thioester of a partially protected peptide segment has been developed. The DNA-binding domain of c-Myb protein (142-193) was synthesized by this method to estimate its usefulness. The partially protected peptide segments, Boc-[Lys(Boc)143,144,160]-c-Myb protein(142-163)-SCH2CH2CONH2 and [Lys(Boc)171,182,192]-c-Myb protein(164-193)-NH2, were highly purified from peptides obtained by a solid-phase method. The thioester in the carboxyl component of the peptide segment was converted to the corresponding p-nitrophenyl ester in the presence of silver ions and p-nitrophenol and then the two segments were condensed. The coupling reaction proceeded almost completely yielding a highly-purified product after removal of Boc groups.