meta-PPISP predicts amino acids that form protein-protein interfaces, with the unbound structure of a protein as input.
The input is a protein structure in PDB format. An input example can be seen here. The user can either upload a structure file or paste it directly on the submission page. A third option is to enter a PDB ID, by clicking "Load Structure From PDB". The server will then retrieve the structure file from the Protein Data Bank (http://www.rcsb.org/pdb/).
The output is either P or N for each residue, indicating it being predicted either as an interface residue or a non-interface residue. An output example, with interactive graphic display, is found here.