“…The functions of proteins correlate with their threedimensional (3D) structures. Based on the information of the 3D structure of proteins, González-Díaz and colleagues developed some models and web servers to discriminate between enzymes and nonenzymes [14,15,39], predict enzyme classes [13], and recognize protein kinases [26,27]. They also developed some quantitative structureactivity relationship (QSAR)-based methods [16,24,25] to classify polygalacturonases and nonpolygalacturonases [1], discriminate dyneins from nondyneins [17], and predict RNase scores [23], achieving encouraging results.…”