Journal Article

FZJ-2016-06506

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Radical Formation Initiates Solvent-Dependent Unfolding and β-Sheet Formation in a Model Helical Peptide

Owen, M. C. (Corresponding author) ; Strodel, B.FZJ* ; Csizmadia, I. G. ; Viskolcz, B.

2016
Soc. Washington, DC

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Please use a persistent id in citations: doi:10.1021/acs.jpcb.6b00174

Abstract: We examined the effects of Cα-centered radical formation on the stability of a model helical peptide, N-Ac-KK(AL)10KK-NH2. Three, 100 ns molecular dynamics simulations using the OPLS-AA force field were carried out on each α-helical peptide in six distinct binary TIP4P water/2,2,2-trifluoroethanol (TFE) mixtures. The α-helicity was at a maximum in 20% TFE, which was inversely proportional to the number of H-bonds between water molecules and the peptide backbone. The radial distribution of TFE around the peptide backbone was highest in 20% TFE, which enhanced helix stability. The Cα-centered radical initiated the formation of a turn within 5 ns, which was a smaller kink at high TFE concentrations, and a loop at lower TFE concentrations. The highest helicity of the peptide radical was measured in 100% TFE. The formation of hydrogen bonds between the peptide backbone and water destabilized the helix, whereas the clustering of TFE molecules around the radical center stabilized the helix. Following radical termination, the once helical structure converted to a β-sheet rich state in 100% water only, and this transition did not occur in the nonradical control peptide. This study gives evidence on how the formation of peptide radicals can initiate α-helical to β-sheet transitions under oxidative stress conditions.

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Contributing Institute(s):

1. Strukturbiochemie (ICS-6)

Research Program(s):

1. 553 - Physical Basis of Diseases (POF3-553) (POF3-553)

Appears in the scientific report 2016

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Database coverage:
; Current Contents - Physical, Chemical and Earth Sciences ; Ebsco Academic Search ; IF < 5 ; JCR ; NCBI Molecular Biology Database ; No Authors Fulltext ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Thomson Reuters Master Journal List ; Web of Science Core Collection

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