| Autor: |
Montalvo GL; Department of Biochemistry & Biophysics, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States., Gai F, Roder H, DeGrado WF |
| Jazyk: |
angličtina |
| Zdroj: |
ACS chemical biology [ACS Chem Biol] 2014 Jan 17; Vol. 9 (1), pp. 276-81. Date of Electronic Publication: 2013 Nov 20. |
| DOI: |
10.1021/cb400621y |
| Abstrakt: |
β-Peptide foldamers offer attractive frameworks for examining the effect of backbone flexibility on the dynamics of protein folding. Herein, we study the folding-unfolding kinetics of a β-peptide, Acid-1Y,1 which folds in aqueous solution into an octameric bundle of peptides in a conformation known as the 14-helix. Acid-1Y is comprised exclusively of β-amino acids, which differ from α-amino acids by the addition of a single methylene into the backbone. We aim to understand how the additional degree of freedom and increased backbone flexibility in the β-amino acid affect folding dynamics and to measure folding rates of this octameric β-peptide. Previously, we found that the T-jump induced relaxation kinetics of a monomeric β-peptide that forms a monomeric 14-helix occurred on the nanosecond time scale2 and were noticeably slower than a similar alanine-based α-helical peptide.3 Additionally, in comparison to similar α-helices, the relaxation rates showed a weaker dependence on temperature. Here, we find that the T-jump induced relaxation kinetics of the octameric β-peptide occurs on an even slower time scale (minutes) and the unfolding relaxation rates show a large dependence on temperature. These differences indicate that folding energy landscapes of β-peptide secondary and quaternary structure are markedly distinct from one another and also from their α-helical counterparts. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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