Effect of pressure on the secondary structure of coiled coil peptide GCN4-p1.
It has recently been demonstrated that pressure induces folding of the alpha-helix of an alanine-based peptide (AK20), which is a monomer in water (Imamura and Kato, Proteins 2009;76:911-918). The present study focused on a coiled coil peptide GCN4-p1, the alpha-helices of which associate via a hydrophobic core, to examine whether the pressure stability of the alpha-helices depends on the hydrophobic core. Fourier transform infrared spectroscopy was used to investigate the effect of pressure on the secondary structures of GCN4-p1. The infrared spectra of GCN4-p1 shows the two amide I' peaks at approximately 1650 and approximately 1630 cm(-1) stemming from the solvent-inaccessible alpha-helix and the solvent-accessible alpha-helix, respectively. The intensities of both the peaks increase with increasing pressure, whereas they decrease with increasing temperature. This indicates that pressure induces both the alpha-helices of GCN4-p1 to fold. The present result suggests that the positive volume change upon unfolding of an alpha-helix is a common characteristic of peptides. The pressure-induced stabilization of the alpha-helices is discussed in comparison with the pressure denaturation of proteins.
Imamura
Hiroshi
H
Graduate School of Science and Engineering, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan.
Isogai
Yasuhiro
Y
Takekiyo
Takahiro
T
Kato
Minoru
M
D002942:Circular Dichroism; D010455:Peptides / Q000737:chemistry*; D011312:Pressure; D017510:Protein Folding; D017433:Protein Structure, Secondary; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature
D010455:Peptides