Development of a Linker with an Enhanced Stability for the Preparation of Peptide Thioesters and Its Application to the Synthesis of a Stable-Isotope-Labelled HU-Type DNA-Binding Protein

Abstract

Abstract An S-alkyl-thioester-moiety-containing linker with an enhanced stability on a resin has been developed. A linker containing S-alkyl thioester with a spacer group, –CO–SC(CH3)2CH2CO–Nle–, was stable during the peptide chain elongation cycle. This thioester was stable under HF treatment conditions, and was rapidly activated by silver ions in the presence of N-hydroxysuccinimde (HONSu) to form a peptide bond. Using this linker, peptide segments covering the HU-type DNA-binding protein of Bacillus stearothermophilus (HBs), which was site-specifically labelled with 2H, 13C, and 15N, were prepared. Using these peptide segments, multi-labelled HBs was synthesized. Distinct signals of 2H, 13C, and 15N in HBs were detected by NMR spectrometry.