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Chemical Modification of the N Termini of Unprotected Peptides for Semisynthesis of Modified Proteins by Utilizing a Hydrophilic Protecting Group
Author(s) -
Chandrashekar Chaitra,
Okamoto Ryo,
Izumi Masayuki,
Kajihara Yasuhiro
Publication year - 2019
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201901778
Subject(s) - semisynthesis , peptide , native chemical ligation , n terminus , biochemistry , recombinant dna , chemistry , peptide sequence , tobacco etch virus , protease , target peptide , chemical ligation , lysine , amino acid , biology , cysteine , enzyme , virus , potyvirus , virology , plant virus , gene
A simple and efficient strategy for the selective modification of the peptide N terminus with an unnatural amino acid is described. A peptide having a SUMO‐HisTag‐TEV sequence (SUMO: small ubiquitin‐related modifier, TEV: tobacco etch virus) preceding the N terminus of the target peptide was designed. Recombinant expression in E. coli and subsequent SUMO protease cleavage yielded the HisTag‐TEV‐target peptide. Partial protection of the lysine side chains of this peptide with d ‐glucopyranosyloxycarbonyl and removal of the HisTag‐TEV sequence by TEV protease yielded the partially protected peptide with a free N‐terminal amine. Coupling of selenocysteine selectively at the N terminus and subsequent acidic deprotection of the carbohydrate protecting groups yielded a modified peptide that can be used for native chemical ligation (NCL). As a proof of concept, the modification of a longer recombinant peptide with selenocysteinylserine (GalNAc) at the N terminus was demonstrated.