Infrared signature and folding dynamics of a helical beta-peptide.
Synthetic foldamers consisting of beta-amino acids offer excellent model systems for examining the effect of backbone flexibility on the dynamics of protein folding. Herein, we study the folding-unfolding kinetics of a beta-peptide that folds into a 14-helical structure in water. We find that the T-jump induced relaxation kinetics of this peptide occur on the nanosecond time scale and are noticeably slower than those of alanine-based alpha-helical peptides, and additionally, the relaxation rates show a weaker dependence on temperature. These differences appear to indicate that the folding energy landscapes of these peptides are different. In addition, we find that the amide I' band of this beta-peptide exhibits a sharp feature at approximately 1612 cm(-1), which we believe is a distinct infrared reporter of 14-helix.
Montalvo
Geronda
G
Department of Biochemistry & Biophysics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
Waegele
Matthias M
MM
Shandler
Scott
S
Gai
Feng
F
DeGrado
William F
WF
D000595:Amino Acid Sequence; D019985:Benchmarking; D007259:Infrared Rays; D007700:Kinetics; D007834:Lasers; D010455:Peptides / Q000737:chemistry*; D011489:Protein Denaturation; D017510:Protein Folding; D017433:Protein Structure, Secondary; D013696:Temperature; D014867:Water / Q000737:chemistry
D010455:Peptides; D014867:Water