ISPRED4 (Interaction Site PREDictor version 4) is a web-server for predicting protein-protein interaction sites starting from protein structure. ISPRED4 adopts machine-learning methods (SVM+CRF) to predict interaction state of each residue in the protein surface by extracting several features from protein sequence and structure.

To start using ISPRED4 you simply need to upload a protein 3D structure in PDB format and specify the protein chain you want to analyze. You can also specificy a RSA threshold to select surface residues (all residues with RSA above the threshold are considered surface residues. Default value is: 0.20). Therefore, press the "Start prediciton" button to submit your job. The server accepts in input a single protein structure.