Gupta, A. and Mehrotra, R. and Klimov, E. and Siesler, H. W. and Joshi, R. M. and Chauhan, V. S. (2006) Thermal stability of dehydrophenylalanine-containing model peptides as probed by infrared spectroscopy: a case study of an alpha-helical and a 3(10)-helical peptide. Chemistry and Biodiversity, 3 (3). pp. 284-295. ISSN 1612-1872

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The temperature-dependent secondary-structural changes in the two known helical model peptides Boc-Val-Delta Phe-Ala-Leu-Gly-OMe (1; alpha-helical) and Boc-Leu-Phe-Ala-Delta Phe-Leu-OMe (2; 3(10)-helical), which both comprise a single dehydrophenylalanine (APhe) residue, were investigated by means of FR-IR spectroscopy (pcptide film on KBr). Both the first-order and the better-resolved second-order derivative IR spectra of 1 and 2 were analyzed. The v(NH) (3240-3340 cm(-1)), the Amide-I (1600- 1700 cm(-1)), and the Amide-II (1510- 1580 cm(-1)) regions of 1 and 2 showed significant differences in thermal-denaturation experiments (22 degrees -> 144 degrees), with the 310-helical peptide (2) being considerably more stable. This observation was rationalized by different patterns and strengths of intramolecular H-bonds, and was qualitatively related to the different geometries of the peptides. Also, a fair degree of residual secondary-structural elements were found even in the 'denatured' states above 104 degrees (1) or 134 degrees (2).

Item Type: Article
Additional Information: Copyright for this article belongs to M/s Wiley-VCH Verlag.
Subjects: Biochemistry & Molecular Biology
Depositing User: Users 27 not found.
Date Deposited: 09 Aug 2018 07:02
Last Modified: 09 Aug 2018 07:02

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