  The correct prediction of protein secondary structures is one of the key
issues in predicting the correct protein folded shape, which is used for
determining gene function. Existing methods make use of amino acids properties
as indices to classify protein secondary structures, but are faced with a
significant number of misclassifications. The paper presents a technique for
the classification of protein secondary structures based on protein
"signal-plotting" and the use of the Fourier technique for digital signal
processing. New indices are proposed to classify protein secondary structures
by analyzing hydrophobicity profiles. The approach is simple and
straightforward. Results show that the more types of protein secondary
structures can be classified by means of these newly-proposed indices.
