Preparation of S-Protected Cysteine-Containing Peptide Thioester and Its Use for the Synthesis of the Barnase-Like Domain in DNA-Directed RNA Polymerase II of Saccharomyces cerevisiae.

The Barnase-like Domain in DNA-Directed RNA Polymerase II of Saccharomyces cerevisiae containing three cysteine residues was synthesized by a thioester method. A partially-protected cysteine-containing peptide thioester was prepared via a peptide obtained by a solid-phase method using 3-nitro-2-pyridinesulfenyl amino acid derivatives. Four peptide segments covering 112 amino acid residues of the barnase-like domain were condensed from the C-terminal to the N-terminal one by one in the presence of silver ions and N-hydroxysuccinimide to give a full sequence peptide. RNase activity of the synthetic domain could not be detected because of its extreme low solubility in the neutral buffer.