کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
9590544 | 1507002 | 2005 | 5 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Substituent effects on long-range interactions in the β-sheet structure of oligopeptides
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موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی تئوریک و عملی
پیش نمایش صفحه اول مقاله
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چکیده انگلیسی
The energetic stabilization and geometrical parameters of the β-sheet structure of three oligopeptides l-Alan, selected conformers of l-Valn and l-Sern (n=2-10) have been investigated by DFT computations. The data reveal the important effect of long-range interactions operating through hydrogen bonding and dipole-dipole interactions. Compared with related data on Glyn oligopeptides determined in our previous study (V. Horváth, Z. Varga, A. Kovács, J. Phys. Chem. A, 2004, 108, 6869-6873), the methyl, i-propyl and hydroxymethyl substituents lead to a decrease of the long-range interactions. While the energy gain from these interactions of a Gly unit in Gly10 was 2.4 kJ/mol, the contribution decreased to 2.1, 1.8, and 0.4 kJ/mol in Ala10, Val10, and Ser10, respectively. Variations of the geometrical parameters (most important being the lengths of Hâ¯O hydrogen-bonds and the C-N bonds) are in agreement with the decrease of the stabilization energies. Another important effect of the substituents is that their steric interactions introduce irregularities in the build-up of energetic and geometric trends, in contrast to their monotonous build-up in Glyn.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Molecular Structure: THEOCHEM - Volume 755, Issues 1â3, 30 November 2005, Pages 247-251
Journal: Journal of Molecular Structure: THEOCHEM - Volume 755, Issues 1â3, 30 November 2005, Pages 247-251
نویسندگان
Viktória Horváth, Zoltán Varga, Attila Kovács,