Self-assembly as a molecular strategy of improve adsorbents of pollutants in water.

Although a lot of progress have been made in studying the molecules mechanism of peptide assembly, it remains a challenge to accurately regulate the assembly structure of peptides to achieve pre-designed structure and function. Chirality, an inherent property of peptides, has been recognized as a vital factor that can exert essential impacts on peptide assembly structures. In the development of peptide biomaterial, the chirality of peptide and amino acid residues is an important factor that has been taken into consideration by researchers. Numerous helical or twisted nanostructures and ordered ensembles have been successfully produced by molecular self-assembly from either single or multiple molecular components but it still remains a challenge to construct chiral nanostructures with desirable conformation (i.e., right-handed, P; left-handed, M) from specific chiral building blocks at will. Alternating D,L-oligopeptides are able to assume specific conformations including, among others, various kinds of single and double stranded β-helical structures. In previous study the conformational characteristics of Boc-(L-Val- D-Val)4-OMe in solution have been investigated by using NMR techniques. Different species that interconvert slowly compared with the proton spin time scale occur in chloroform solution and two of them are left-handed, doublestranded helical species of the type ↓↑β5.6 with 14 interstrand hydrogen bonds (Figure1). As illustrated in Figure 1 in the helix A the hydrogen bonds connect three pairs of D residues and four pairs of L residues, in the helix B the hydrogen bonds connect four pairs of D residues and three pairs of L residues. Note that the helix A can be converted into helix B (or vice versa) simply by transposing one strand by two residues with respect to the other. Here we report about synthesis and conformational behavior of a peptidic system that can be used for the removal of a wide variety of micropollutants of different size from natural and engineered water systems. References:[1] D.U. Römer, E. Fenude-Schoch, G.P. Lorenzi, Helvetica Chimica Acta (1993) 76, 451-458[2] G.P. Lorenzi, H. Jackle, L. Tomasic, V. Rizzo, C. Pedone, J. Am. Chem. Soc. (1985) 104, 1728-1733