Least-squares analysis of circular dichroic spectra of proteins.

It is shown that the method proposed by Baker and Isenberg [Biochemistry, 15, 629 (1976)] for estimating secondary structure composition of proteins from circular dichroic spectra is a least-squares fitting technique. Estimates obtained by this method for myoglobin, lysozyme, lactate dehydrogenase, papain, and ribonuclease are not substantively different from those obtained using unconstrained linear least squares.