2018 年 76 巻 1 号 p. 45-54
Intein-mediated protein splicing system is an autocatalytic process in which an intervening protein sequence (intein) excises itself from the intein-embedded polypeptide sequence; concomitantly creating a new peptide bond between its two flanking sequences (exteins). In the intein-mediated protein splicing, sequentially occurring N-S, S-S, and S-N acyl transfers are cornerstone events. Chemical bases involved in such acyl transfer steps have provided insights of great use for developing wide varieties of chemical methodologies for peptide/protein chemistry. Therefore, we have continued our research efforts to develop innovative methodologies for preparation of peptide thioesters on the basis of “Intein Chemistry”. Peptide/protein thioesters have served as an indispensable synthetic intermediate of tremendous use in native chemical ligation (NCL) which has proven extraordinarily powerful for chemical synthesis or semisynthesis of proteins. In this review, we present the development of both N-sulfanylethylanilide (SEAlide) peptides as a crypto-thioester and chemical protocols for thioester preparation applicable to naturally occurring peptide sequences on the basis of the chemistry found in the intein-mediated protein splicing.