Selective modification of sulfamidate-containing peptides

Synthesis of Fluorescent Lanthipeptide Cytolysin S Analogues by Late-Stage Sulfamidate Ring Opening

Nucleophilic ring opening of cyclic sulfamidates derived from amino acids is a common strategy for the synthesis of lanthionine derivatives. In this work, we report the regio-, chemo-, and stereoselective intramolecular S-alkylation of a cysteine residue with N-sulfonyl sulfamidates for the synthesis of cyclic lanthionine-containing peptides. The strategy involves the solid-phase synthesis of sulfamidate-containing peptides followed by late-stage intramolecular cyclization. This protocol allowed for the synthesis of four full-length cytolysin S (CylLS″) analogues, two α-peptides and two hybrid α/β-peptides. Their conformational preferences and biological activities were assessed and compared with those of wild-type CylLS″.

Conformationally Restricted β-Sheet Breaker Peptides Incorporating Cyclic α-Methylisoserine Sulfamidates

Peptides containing variations of the β-amyloid hydrophobic core and five-membered sulfamidates derived from β-amino acid α-methylisoserine have been synthesized and fully characterized in the gas phase, solid state and in aqueous solution by a combination of experimental and computational techniques. The cyclic sulfamidate group effectively locks the secondary structure at the N-terminus of such hybrid peptides imposing a conformational restriction and stabilizing non-extended structures. This conformational bias, which is maintained in the gas phase, solid state and aqueous solution, is shown to be resistant to structure templating through assays of in vitro β-amyloid aggregation, acting as β-sheet breaker peptides with moderate activity.

Site-selective modification of peptide backbones

Exciting developments in the site-selective modification of peptide backbones are allowing an outstanding fine-tuning of peptide conformation, folding ability, and physico-chemical and biological properties.