title: Partial thioamide scan on the lipopeptaibiotic trichogin GA IV. Effects on folding and bioactivity.
abstract: Backbone modification is a common chemical tool to control the conformation of linear peptides and to explore potentially useful effects on their biochemical and biophysical properties. The thioamide, ψ[CS-NH], group is a nearly isosteric structural mimic of the amide (peptide) functionality. In this paper, we describe the solution synthesis, chemical characterization, preferred conformation, and membrane and biological activities of three, carefully selected, peptide analogues of the lipopeptaibiotic [Leu(11)-OMe] trichogin GA IV. In each analogue, a single thioamide replacement was incorporated. Sequence positions near the N-terminus, at the center, and near the C-terminus were investigated. Our results indicate that (i) a thioamide linkage is well tolerated in the overall helical conformation of the [Leu(11)-OMe] lipopeptide analogue and (ii) this backbone modification is compatible with the preservation of its typical membrane leakage and antibiotic properties, although somewhat attenuated.
authors.affiliation: ICB, Padova Unit, CNR, Department of Chemistry, University of Padova, 35131 Padova, Italy.
authors.forename: Marta
authors.initials: M
authors.lastname: De Zotti
authors.forename: Barbara
authors.initials: B
authors.lastname: Biondi
authors.forename: Cristina
authors.initials: C
authors.lastname: Peggion
authors.forename: Matteo
authors.initials: M
authors.lastname: De Poli
authors.forename: Haleh
authors.initials: H
authors.lastname: Fathi
authors.forename: Simona
authors.initials: S
authors.lastname: Oancea
authors.forename: Claudio
authors.initials: C
authors.lastname: Toniolo
authors.forename: Fernando
authors.initials: F
authors.lastname: Formaggio