their LJ sigma parameter increased with respect to the standard bead size sigma. As a consequence, their LJ minimum is located further apart (Fig ). This impacts interactions between charged (e.g. LYS, ARG, GLU, ASP) and hydrophobic (e.g. ILE, LEU, ALA, VAL) residues (exemplified by the Q5-SC2 interaction, Fig ). The interfaces of many soluble complexes often have some of these residues in close proximity and the Barnase-Barstar complex has one such residue pair at the interface (GLU60-LEU144). Overall, the impact of these issues on protein complex stability is clear, as even in the initial steps of minimization and equilibration, the immediate repulsion between the protein monomers will contribute to the destabilization of the complex.