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

ALCARÁZ, MIRTA R.; SCHWAIGHOFER, ANDREAS; GOICOECHEA, HÉCTOR; LENDL, BERNHARD

SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY.

PERGAMON-ELSEVIER SCIENCE LTD

Año: 2017 vol. 185 p. 304 - 309

1386-1425

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.