This entropy meter represents the transformation of the dynamical indicator of conformational entropy into a quantitative metric. The entropy meter concept has now generalized to 28 protein-ligand complexes with eight different protein receptors . Many of these examples do not have a clear spatial relationship of changes in entropy upon binding. However, it is difficult to discern if this is due to the sporadic methyl side chain probes used to determine the protein conformational entropy or the lack of spatial entropic redistribution in these systems. A spatial pattern is observed in the Catabolite activator protein (CAP), is a dimeric protein that binds DNA in a cAMP-dependent manner . After cAMP binding, CAP undergoes a large conformational change to a state compatible with DNAbinding. A series of mutants with similar overall binding affinities have entropic contributions swing by almost 30 kcal/mol. Across these mutants, the ones with entropically driven binding have increased side chain fluctuations in side chains distal from the DNA-binding site, while the residues near to DNA experience a loss of flexibility. The concept of how entropic contributions cluster in space has also been examined as a function of pressure in ubiquitin and for protein-protein interactions in barnasebarstar . These studies also demonstrate clustering of side chains that increase or decrease flexibility in a correlated manner, suggesting that the redistribution of side chain dynamics may be an evolved feature of proteins to modulate the free energy of folding and binding.