Pressure-induced structural changes of alanine oligopeptides in aqueous solutions. Issue 2 (3rd April 2019)

• Record Type: Journal Article
• Authors: Takekiyo, Takahiro; Kato, Minoru; Yoshimura, Yukihiro
• Is Part Of: High pressure research. Volume 39:Issue 2(2019)
• Page Start: 202
• Page End: 209
• Publication Date: 2019-04-03
• Subjects: Alanine-oligopeptides -- conformational change -- high pressure -- FTIR spectroscopy; High pressure (Science) -- Periodicals; High pressure (Technology) -- Periodicals; 536.41
• DOI: 10.1080/08957959.2019.1584195
• Languages: English
• ISSNs: 0895-7959

Abstract

ABSTRACT: Short alanine (Ala) oligopeptides in aqueous solution adopt polyproline II [PPII; ( φ, ψ ) = (−60°, 150°)] and extended β conformations [( φ, ψ ) = (−150°, 150°)], whose conformers are related to the denatured state of proteins. In this study, we investigated pressure-induced conformational changes of penta- and hexa-alanines (Ala5 and Ala6, respectively) in aqueous solutions using Fourier-transform infrared (FTIR) spectroscopy. A remarkable observation was that two peaks at 1620 and 1690 cm −1 in Ala6 assigned to the intermolecular β-sheets were generated with increasing pressure. These peaks were not observed in Ala5 . Our analyses of absorbance changes and frequency shifts further suggested that pressure was responsible for the PPII → β conformational change of Ala5, and the PPII → intermolecular β-sheet structure of Ala6, respectively. These results indicated a differing conformational stability of Ala5 under high pressure as compared with Ala6 .