TY  - JOUR
AU  - Schrader, T.E.
AU  - Cordes, T.
AU  - Schreier, W.J.
AU  - Koller, F.O.
AU  - Dong, S.-L.
AU  - Moroder, L.
AU  - Zinth, W.
TI  - Folding and Unfolding of Light Triggered beta-Hairpin Model Peptides
JO  - The journal of physical chemistry  / B
VL  - 115
SN  - 1520-6106
CY  - Washington, DC
PB  - Soc.
M1  - PreJuSER-20194
SP  - 5219 - 5226
PY  - 2011
N1  - 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.
AB  - 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.
KW  - Amino Acid Sequence
KW  - Azo Compounds: chemistry
KW  - Inverted Repeat Sequences
KW  - Peptides: chemistry
KW  - Protein Folding
KW  - Protein Structure, Secondary
KW  - Protein Unfolding
KW  - Spectrophotometry, Infrared
KW  - Azo Compounds (NLM Chemicals)
KW  - Peptides (NLM Chemicals)
KW  - azobenzene (NLM Chemicals)
KW  - J (WoSType)
LB  - PUB:(DE-HGF)16
C6  - pmid:21175125
UR  - <Go to ISI:>//WOS:000290127100018
DO  - DOI:10.1021/jp107683d
UR  - https://juser.fz-juelich.de/record/20194
ER  -