Picosecond conformational transition and equilibration of a cyclic peptide.
Ultrafast IR spectroscopy is used to monitor the nonequilibrium backbone dynamics of a cyclic peptide in the amide I vibrational range with picosecond time resolution. A conformational change is induced by means of a photoswitch integrated into the peptide backbone. Although the main conformational change of the backbone is completed after only 20 ps, the subsequent equilibration in the new region of conformational space continues for times >16 ns. Relaxation and equilibration processes of the peptide backbone occur on a discrete hierarchy of time scales. Albeit possessing only a few conformational degrees of freedom compared with a protein, the peptide behaves highly nontrivially and provides insights into the complexity of fast protein folding.
Universität Zürich, Physikalisch Chemisches Institut, Winterthurer Strasse 190, Switzerland.
Jens
J
Bredenbeck
Jan
J
Helbing
Arne
A
Sieg
Tobias
T
Schrader
Wolfgang
W
Zinth
Christian
C
Renner
Raymond
R
Behrendt
Luis
L
Moroder
Josef
J
Wachtveitl
Peter
P
Hamm
D010456:Peptides, Cyclic / Q000737:chemistry*; D011487:Protein Conformation; D013055:Spectrophotometry, Infrared
D010456:Peptides, Cyclic