Application of MCR-ALS to reveal intermediate conformations in the thermally induced α-β transition of poly-l-lysine monitored by FT-IR spectroscopy

• Published in: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy Vol. 185; pp. 304 - 309
• Main Authors: Alcaráz, Mirta R., Schwaighofer, Andreas, Goicoechea, Héctor, Lendl, Bernhard
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 05.10.2017
• Subjects: Conformational analysis; Fourier transform infrared spectroscopy; Multivariate curve analysis–alternating least squares; Poly-l-lysine; Secondary structure; Fourier transform infrared spectroscopy; Secondary structure; Multivariate curve analysis–alternating least squares; Conformational analysis; Poly-l-lysine
• ISSN: 1386-1425; 1873-3557
• DOI: 10.1016/j.saa.2017.05.005

Temperature-induced conformational transitions of poly-l-lysine were monitored with Fourier-transform infrared (FT-IR) spectroscopy between 10°C and 70°C. Chemometric analysis of dynamic IR spectra was performed by multivariate curve analysis–alternating least squares (MCR-ALS) of the amide I′ and amide II′ spectral region. With this approach, the pure spectral and concentration profiles of the conformational transition were obtained. Beside the initial α-helical, the intermediate random coil/extended helices and the final β-sheet structure, an additional intermediate PLL conformation was identified and attributed to a transient β-sheet structure. [Display omitted] •Temperature-induced structural change of poly-l-lysine was monitored by FT-IR spectroscopy.•MCR-ALS was performed to distinguish and characterize the involved structural conformations.•Beside the initial α-helical and final β-sheet structure, two intermediate conformations have been identified.