Δ" #$%& = " )* -(" ) + " * ) [1] Were P and L stand for protein and ligand, respectively (in their complex-structure geometry). It should be pointed out that the relationship between such calculated energetics and realistic PL systems is quite unclear (as said, PL binding is a continuous, dynamic process; representing it using such "binary" means -i.e., bound complex vs. free structuresclearly ignores this fact); still, quite a few authors have employed such quantities as bits and pieces of information in more-general predictive theoretical/computational schemes -where additional such pieces, obtained using different techniques (e.g., classical MD trajectories), are also used. Needless to say, such multi-method efforts require an appropriate multimethod-expertise from the researcher, and entail lots of (perhaps undetectable) sources of error and technical difficulties -as demonstrated in Figure .