Analytical characterization of the conformational transitions of polynucleotides by means of different molecular spectroscopies and multivariate curve resolution.

A general procedure for the study of conformational transitions of polynucleotides is described. The equilibria between different conformations induced by salt, ethidium bromide, and temperature of poly(dG-dC). poly(dG-dC) and induced by salt and temperature of poly(A). poly(U) are investigated using molecular absorption, circular dichroism, and fluorescence spectroscopies. Spectral data obtained from experiments are analyzed by means of a factor analysis method, namely, multivariate curve resolution, which allows possible intermediate states to be detected and the pure spectra and the concentration profiles of all species present in the system to be estimated. This work shows the application of this procedure for the analysis of data matrices obtained in individual experiments but also for the analysis of several data matrices simultaneously. Copyright 2001 Academic Press.