Computational Study on the Conformation and Vibration Frequencies of β-Sheet of ε-Polylysine in Vacuum

Abstract

Two oligomers, each containing 3 l-lysine residues, were used as model molecules for the simulation of the β-sheet conformation of ɛ-polylysine (ɛ-PLL) chains. Their C terminals were capped with ethylamine and N terminals were capped with α-l-aminobutanoic acid, respectively. The calculations were carried out with the hybrid two-level ONOIM (B3LYP/6-31G:PM3) computational chemistry method. The optimized conformation was obtained and IR frequencies were compared with experimental data. The result indicated that the two chains were winded around each other to form a distinct cyclohepta structure through bifurcated hydrogen bonds. The groups of amide and α-amidocyanogen coming from one chain and the carbonyl group from the other chain were involved in the cyclohepta structure. The bond angle of the bifurcated hydrogen bonds was 66.6°. The frequency analysis at ONIOM [B3LYP/6-31G (d):PM3] level showed the IR absorbances of the main groups, such as the amide and amidocyanogen groups, were in accordance with the experimental data.

Water dynamics in the hydration shells of biological and non-biological polymers

“…However, in aqueous solutions, ε-PLL folds into a three-dimensional β-sheet structure. 18,19 The temperature dependences of the relaxation processes observed in this solution are shown in Fig. 1(a).…”

Controlled Selective Formation of Amadori Compounds from α/ε Mono- or Di-glycation of Lysine with Xylose

“…5,6 The type of amino acids and reducing sugars could affect the components of their ARPs and MRPs. 7 Lysine (Lys) is a basic amino acid containing two active sites of −NH 2 (α-and ε-NH 2 ), 8 both of which are highly reactive to interact with reducing sugars to form different Lys-ARPs. 9,10 It is worth noting that, mono-substituted ARPs of Lys in which the glycation is solely at the αor ε-amino position of Lys still have a reactive free amino group (ε-NH 2 or α-NH 2 ).…”

Advanced Delivery Systems Based on Lysine or Lysine Polymers

“… However, fewer studies have been done on the conformation of ε-polylysine. FTIR, Raman spectroscopy, CD analyses and also computational studies on the ε-polylysine in the aqueous media show that the conformation of this type of polylysine is β-sheet. , …”

“…FTIR, Raman spectroscopy, CD analyses and also computational studies on the ε-polylysine in the aqueous media show that the conformation of this type of polylysine is β-sheet. 36,37 The chemical structure of polylysine has a significant impact on its drug delivery application. 38,39 Three main chain structures of polylysine are widely used for drug delivery applications: linear, dendritic, and hyperbranch (Figure 2).…”