Epitope and paratope region analysis

A conformational epitope (CE) in an antigenic protein is composed of amino acid residues that are spatially near each other on the antigen's surface but discontinuously appeared in sequence. CEs bind their complementary Para topes which are located on the surface areas of B-cell receptors and/or antibodies. CE predication is a challenging research topic, which plays an important and fundamental role for vaccine design and immuno-biological experiments. The aim of this study is to primarily analyze CE epitopes of 163 non-redundant antigen structures based on physical and chemical properties of surface residues. In terms of physical properties, distinguishable geometric features of solid angle and surface rate of amino acids are observed, while for chemical properties, higher energy, hydrophilicity and polarity from verified epitope regions are discovered as well. All these recognized features from verified CEs were thoroughly analyzed and compared for supporting a CE prediction system.