For the calculations of the protein-ligand interactions using our new MFCC-MBE(2) scheme, Figure illustrates the convergence with respect to the chosen cutoff λ. In all cases, it is obvious that the successive inclusion of three-body contributions with increasing cutoff systematically reduces the error of the conventional MFCC scheme. While in most cases, this error reduction in rather monotonic, in some cases (in particular for 1STP, 1TOW and 2IFB) there is some oscillating behavior. Nevertheless, in general the calculated MFCC-MBE(2) interaction energy starts to stabilize at approximately λ = 4 Å. As this value represents a good compromise between convergence of the three-body contributions and the required computational effort, we included the MFCC-MBE(2) calculated for λ = 4 Å in Table .