AMINO-ACID SIDE-CHAIN DESCRIPTORS FOR QUANTITATIVE STRUCTURE-ACTIVITYRELATIONSHIP STUDIES OF PEPTIDE ANALOGS

This report describes a new set of amino acid side chain descriptors, the isotropic surface area (ISA), and the electronic charge index (ECI ) relevant to peptide quantitative structure-activity relationship (QS AR) studies. These features are derived from optimized three-dimension al structures of the natural and unnatural amino acids. Since the desc riptors are derived considering side chain three-dimensional structure , 3D-QSARs result. Using the method of partial least squares, 3D-QSARs of peptide sets were developed. A comparison of the results to those obtained with the principal properties or z-scales shows that the ISA and ECI are comparable for parameterizing the structural variability o f the peptide series and represent an interesting alternative.