The α-Helix Folds More Rapidly at the C-Terminus Than at the N-Terminus

Abstract

The helix-coil dynamics of different sections of an alpha-helical model peptide were observed separately by nanosecond temperature jump experiments with IR detection on a series of isotopically labeled peptides. The results show that the helix-coil dynamics of the alpha-helical C-terminus are faster than those of the N-terminus.

Nanosecond T-Jump Experiment in Poly(glutamic acid): A Circular Dichroism Study

“…Indeed, the precise position of the Amide I’ bands is slightly dependent on the secondary structure. This technique has already brought many impressive results [8,9]. However, it suffers from a lack of quantitative estimation of the helix content.…”

Time-resolved temperature-jump infrared spectroscopy of peptides with well-defined secondary structure: A Trpzip β-hairpin variant as an example

“…Protein fragments or designed peptides with welldefined secondary structures have been used in a variety of studies to probe the initial steps of protein folding. a-Helical peptides of various sizes and sequences were found to fold in the submicrosecond time range [8][9][10][11][12][13][14]. Also several studies on b-hairpins have been performed [15][16][17][18][19][20][21][22][23].…”

Local conformational dynamics in α-helices measured by fast triplet transfer

“…T-jump relaxation dynamics using an N-terminal fluorescence probe revealed faster helix unfolding in the N-terminal region compared with the decrease in average helix content (8). Site-specific IR studies on 13 C-labeled peptides, in contrast, suggested only little position dependence of the relaxation times after a T-jump (22,(25)(26)(27). These studies gave insight into the kinetics of perturbationinduced helix unfolding, but they did not yield information on the dynamic properties of ␣-helices under equilibrium conditions.…”