Journal Article

PreJuSER-20194

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Folding and Unfolding of Light Triggered beta-Hairpin Model Peptides

Schrader, T. E.FZJ* ; Cordes, T. ; Schreier, W. J. ; Koller, F. O. ; Dong, S.-L. ; Moroder, L. ; Zinth, W.

2011
Soc. Washington, DC

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Please use a persistent id in citations: doi:10.1021/jp107683d

Abstract: Ultrafast spectroscopy in the visible and mid-infrared is used to study the reaction dynamics of two light-triggered model peptides containing an azobenzene derivative as a switching element. One model peptide, the AzoTrpZip2, forms a β-hairpin structure in the cis form of the chromophore. This peptide is compared to the core structure consisting of the chromophore and the two flanking amino acid residues, used as a minimal model. This combination of experiments performed in different spectral ranges on peptides of different sizes allows for improved insight into light triggered reaction dynamics. The kinetics observed for the core structure are directly connected to the switching process of the chromophore and are finished on the 10 ps time scale. The trans-to-cis reaction of AzoTrpZip2, leading to the formation of the β-hairpin structure involves ultrafast processes on the 100 ps time scale, which are directly related to the relaxation of the strain between the isomerized molecular switch and the two peptide strands. IR-signatures characteristic for changes in interstrand interactions are absent on the <1 ns time scale. Thus folding into the β-hairpin structure occurs on a much longer time scale. In the cis-to-trans unfolding reaction, all IR signatures related to changes in interstrand interactions occur within 1 ns, in a time range where visible spectroscopy reveals the final decay of the intramolecular strain. Apparently unfolding of AzoTrpZip2 is to a large extent a fast, driven process.

Keyword(s): Amino Acid Sequence (MeSH) ; Azo Compounds: chemistry (MeSH) ; Inverted Repeat Sequences (MeSH) ; Peptides: chemistry (MeSH) ; Protein Folding (MeSH) ; Protein Structure, Secondary (MeSH) ; Protein Unfolding (MeSH) ; Spectrophotometry, Infrared (MeSH) ; Health and Life (1st) ; Health and Life (1st) ; Biology (2nd) ; Azo Compounds ; Peptides ; azobenzene ; J

Note: The authors thank Alexander Milbradt, Christian Renner, and Markus Loweneck for synthesis of the molecules and NMR analysis, and Ulrike Kusebauch for helpful discussions. Financial support from the Deutsche Forschungsgemeinschaft (SFB 533 Projects A8, B9, and SFB 749, project A5) is highly acknowledged. This work was also supported through the DFG-Cluster of Excellence Munich-Centre for Advanced Photonics. The authors thank Shaul Mukamel for many helpful discussions on light triggered peptides.

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Contributing Institute(s):

1. Neutronenstreuung (ICS-1)
2. JCNS-FRM-II (JCNS (München) ; Jülich Centre for Neutron Science JCNS (München) ; JCNS-FRM-II)
3. Neutronenstreuung (JCNS-1)

Research Program(s):

1. BioSoft: Makromolekulare Systeme und biologische Informationsverarbeitung (P45)
2. Großgeräte für die Forschung mit Photonen, Neutronen und Ionen (PNI) (P55)

Experiment(s):

1. No specific instrument

Appears in the scientific report 2011

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