Calculates the physicochemical properties and amino acid composition. HELIQUEST uses the results to screen any databank in order to identify protein segments possessing similar features. It allows users to determine online the features of known helices and using the results as a starting point to extract equivalent helices in unexpected proteins. This tool can analyzed a sequence submitted by the user. The analyze is done by a sliding window. It uses an algorithm which detects the existence of an uninterrupted hydrophobic face of at least five residues adjacent on a helical wheel.