This webserver allows you to estimate protein secondary structure from circular dichroism (CD) spectra using the method of:
Raussens V, Ruysschaert JM, Goormaghtigh E., (2003) "Protein concentration is not an absolute prerequisite for the determination of secondary structure from circular dichroism spectra: a new scaling method.", Anal Biochem., p114-21
The method is concentration independent, so it is particularily useful for getting a rough estimate in situations where determining an accurate protein concentration is hard (eg in the prescence of A
Note that there was an erratum issued by the authors in Anal Biochem. 2006 Dec 1;359(1):150. This server uses the corrected equations, which change the estimates for alpha-helix and beta-strand compared with the originally published and erroneous method.