I am using STRING database to check for interactions between two interacting proteins for my study. However, I have been unable to fish out the individual amino acids which are taking part in interacting proteins.
you may try PyDOCK (https://life.bsc.es/pid/pydockweb/) for protein-protein docking and find out the interface residues responsible for forming interactions.
If structure of the two proteins in complex is known then one can get find the interface of the interaction and the amino acids involved. If not then, prediction based strategies using insilico approach can be used which needs to be validated by other invitro techniques.
According to CARd of analysis, I can suggest amino acid involved in interaction between two proteins, but the point is carbon profile needs to be studied both at structural or sequence level. For that you may contact me further on or check my papers online. All the best.