Self-Assembly of Fluorinated Sugar Amino Acid Derived α,γ-Cyclic Peptides into Transmembrane Anion Transport

Syntheses of fluorinated sugar amino acid derived α,γ-cyclic tetra- and hexapeptides are reported. The IR, NMR, ESI-MS, CD, and molecular modeling studies of cyclic tetra- and hexapeptides showed C₂ and C₃ symmetric flat oval- and triangular-ring shaped β-strand conformations, respectively, which appear to self-assemble into nanotubes. The α,γ-cyclic hexapeptide (EC₅₀ = 2.14 μM) is found to be a more efficient ion transporter than α,γ-cyclic tetrapeptide (EC₅₀ = 14.75 μM). The anion selectivity and recognition of α,γ-cyclic hexapeptide with NO₃^– ion is investigated.