Searching for quantitative entropy-enthalpy compensation among protein variants.
Entropy-enthalpy (SH) compensation occurs when a small change in DeltaG is caused by large, and nearly compensatory, changes in DeltaH and DeltaS. It is considered a ubiquitous property of reactions in water. Because water is intimately involved in protein stability, SH compensation among protein variants, if it exists, could lead to important knowledge about protein-water interactions. In light of recent theoretical work on SH compensation, we gathered thermodynamic data for >200 protein variants to seek evidence for the simplest quantitative model of SH compensation (i.e., The van't Hoff denaturation enthalpy divided by the van't Hoff denaturation entropy is a constant). We conclude that either the data are insufficient to support the idea that quantitative SH compensation is a general feature of variant proteins or that such compensation does not exist. This study reinforces the idea that DeltaH-versus-DeltaS plots should not be used to provide evidence for SH compensation.
D003574:Cytochrome c Group / Q000737:chemistry / Q000235:genetics; D019277:Entropy; D006801:Humans; D008836:Micrococcal Nuclease / Q000737:chemistry / Q000235:genetics; D008962:Models, Theoretical; D009113:Muramidase / Q000737:chemistry / Q000235:genetics; D009154:Mutation; D011489:Protein Denaturation; D011506:Proteins / Q000737:chemistry*; D006163:Ribonuclease T1 / Q000737:chemistry / Q000235:genetics; D013816:Thermodynamics
D003574:Cytochrome c Group; D011506:Proteins; D006163:Ribonuclease T1; D008836:Micrococcal Nuclease; D009113:Muramidase