title: C-terminal peptide extension via gas-phase ion/ion reactions.
abstract: The formation of peptide bonds is of great importance from both a biological standpoint and in routine organic synthesis. Recent work from our group demonstrated the synthesis of peptides in the gas-phase via ion/ion reactions with sulfo-NHS reagents, which resulted in conjugation of individual amino acids or small peptides to the N-terminus of an existing 'anchor' peptide. Here, we demonstrate a complementary approach resulting in the C-terminal extension of peptides. Individual amino acids or short peptides can be prepared as reagents by incorporating gas phase-labile protecting groups to the reactive C-terminus and then converting the N-terminal amino groups to the active ketenimine reagent. Gas-phase ion/ion reactions between the anionic reagents and doubly protonated "anchor" peptide cations results in extension of the "anchor" peptide with new amide bond formation at the C-terminus. We have demonstrated that ion/ion reactions can be used as a fast, controlled, and efficient means for C-terminal peptide extension in the gas phase.
authors.affiliation: Department of Chemistry Purdue University West Lafayette, Indiana, USA 47907-2084.
authors.forename: Zhou
authors.initials: Z
authors.lastname: Peng
authors.affiliation: Department of Chemistry Purdue University West Lafayette, Indiana, USA 47907-2084.
authors.forename: Scott A
authors.initials: SA
authors.lastname: McLuckey
keywords: Woodward’s reagent K; ion/ion reaction; peptide bond formation