Computational study on the conformation and vibration frequencies of ß-sheet of ε-polylysine in vacuum.
Int J Mol Sci
; 10(8): 3358-3370, 2009 Jul 29.
Article
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| MEDLINE
| ID: mdl-20111685
ABSTRACT
Two oligomers, each containing 3 l-lysine residues, were used as model molecules for the simulation of the beta-sheet conformation of varepsilon-polylysine (varepsilon-PLL) chains. Their C terminals were capped with ethylamine and N terminals were capped with alpha-l-aminobutanoic acid, respectively. The calculations were carried out with the hybrid two-level ONOIM (B3LYP/6-31GPM3) 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 alpha-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 degrees . 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.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Polilisina
/
Modelos Moleculares
Idioma:
En
Revista:
Int J Mol Sci
Año:
2009
Tipo del documento:
Article
País de afiliación:
China