Abstract: Two oligomers, each containing 3 L-lysine residues, were used as model molecules for the simulation of the β-sheet conformation of ε-polylysine (ε-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.
Keywords: cyclohepta bifurcated hydrogen bond; ε-polylysine; peptide; ONIOM
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Jia, S.; Mo, Z.; Dai, Y.; Zhang, X.; Yang, H.; Qi, Y. Computational Study on the Conformation and Vibration Frequencies of β-Sheet of ε-Polylysine in Vacuum. Int. J. Mol. Sci. 2009, 10, 3358-3370.
Jia S, Mo Z, Dai Y, Zhang X, Yang H, Qi Y. Computational Study on the Conformation and Vibration Frequencies of β-Sheet of ε-Polylysine in Vacuum. International Journal of Molecular Sciences. 2009; 10(8):3358-3370.
Jia, Shiru; Mo, Zhiwen; Dai, Yujie; Zhang, Xiuli; Yang, Hongjiang; Qi, Yuhua. 2009. "Computational Study on the Conformation and Vibration Frequencies of β-Sheet of ε-Polylysine in Vacuum." Int. J. Mol. Sci. 10, no. 8: 3358-3370.