All protein structures were downloaded from the RCSB Protein Data Bank. Some of the structures required further processing. In PDB: 2OOB, Chain B (Ubiquitin) we built 4 missing residues in the C-terminal (LRGG) using the CHARMM-GUI webserver, as these residues are close to the binding interface and could be important. In PDB: 1BRS, Chain A (Barnase) we built two missing N-terminal residues (AQ) using CHARMM-GUI, and mutated A40C and A82C, restoring two cysteines from the wild-type sequence. A small loop in PDB: 1BRS, Chain B, residue 64-65 (EN) was built using the Maestro Schrodinger v2021.4 Protein Crosslink Tool. In PDB: 1QD6 a loop of residue 26-29 (HDNP) was missing and built using the Maestro Schrodinger v2021.4 Protein Crosslink Tool. In PDB: 1QD6 S114 was covalently linked to a 1-Hexadecanosulfonic Acid which was removed to restore the serine. Crystal water and ions were removed from all structures except PDB: 1OTS where four structural chloride ions were kept (two in each protein monomer at site S cen and S int ).