Polypeptide Synthesis Using the <i>S</i>-Alkyl Thioester of a Partially Protected Peptide Segment. Synthesis of the DNA-Binding Domain of <i>c</i>-Myb Protein (142–193)–NH2

Abstract

Abstract 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.