Effect of pressure on the secondary structure of coiled coil peptide GCN4-p1

• Published in: Biochimica et biophysica acta Vol. 1804; no. 1; pp. 193 - 198
• Main Authors: Imamura, Hiroshi, Isogai, Yasuhiro, Takekiyo, Takahiro, Kato, Minoru
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.01.2010
• Subjects: Alpha-helix; CD spectroscopy; Circular Dichroism; Coiled coil; GCN4-p1; Infrared spectroscopy; Peptides - chemistry; Pressure; Pressure effect; Protein Folding; Protein Structure, Secondary; Spectroscopy, Fourier Transform Infrared; Temperature; Alpha-helix; Infrared spectroscopy; Pressure effect; GCN4-p1; CD spectroscopy; Coiled coil
• ISSN: 1570-9639; 0006-3002; 1878-1454
• DOI: 10.1016/j.bbapap.2009.10.003

It has recently been demonstrated that pressure induces folding of the α-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 α-helices of which associate via a hydrophobic core, to examine whether the pressure stability of the α-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 ∼1650 and ∼1630 cm−1 stemming from the solvent-inaccessible α-helix and the solvent-accessible α-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 α-helices of GCN4-p1 to fold. The present result suggests that the positive volume change upon unfolding of an α-helix is a common characteristic of peptides. The pressure-induced stabilization of the α-helices is discussed in comparison with the pressure denaturation of proteins.