1.D.53 The alpha,gamma-Peptide Nanotube (α,γ-PepNT) Family
One advantage of peptide nanotubes composed of gamma-amino acids is that the properties of their inner cavities can be tuned by introducing different functions on beta-carbon of the gamma-amino acid. The presence of different numbers of hydroxyl groups in different positions in the lumen of these channels when they are inserted into a lipid bilaye determine the ion transport properties of the channel. They affect the structural and dynamic behavior of the modified peptide nanotubes as well as the transmembrane transport of different ions (Calvelo et al. 2015).
Syntheses of fluorinated sugar amino acid derived α,γ-cyclic tetra- and hexapeptides have been accomplished (Burade et al. 2017). 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 beta-strand conformations, respectively, which appear to self-assemble into nanotubes. The α,γ-cyclic hexapeptide (EC50 = 2.14 muM) is found to be a more efficient ion transporter than α,γ-cyclic tetrapeptide (EC50 = 14.75 muM). The anion selectivity and recognition of α,γ-cyclic hexapeptide with NO3- ions has been investigated (Burade et al. 2017).