Theoretical possibility of the chiral recognition of amino acids by a peptide nanoring

By changing the constituent amino acid residues, peptide nanorings (PNRs) are expected to be applicable to molecular separation technology. In this paper, chiral recognition of guest amino acids by a host PNR is studied using ab initio calculations. We designed a theoretical host PNR consisting of four glycine and two D-asparagine residues that would work as a chiral selector even if the guest amino acid is protonated or deprotonated. We then considered the energy stability of the PNR complexes with the D and L bodies of guest amino acids. The PNR showed enhanced properties that could allow for chiral recognition of guest amino acids with polar and dissociable side chains at any solvent pH.