Wrapping Defects Are Sticky

Throughout the book, dehydrons will be referred to in different ways depending on the context. Thus, the terms packing defect, wrapping defect, dehydron, structural deficiency, structural vulnerability will be used synonymously. Far from introducing a notational chaos, this name multiplicity bespeaks of the richness of the concept. 

As indicated above, dehydrons have unique physico-chemical properties They represent structural vulnerabilities of the protein, but they also constitute sticky spots promoting the removal of surrounding water [12-14, 19, 21], This latter property could only be established by addressing the following questions How do we effectively demonstrate that a dehydron attracts nonpolar test groups Can we measure the mechanical equivalent of its dehydration propensity  

For proteins with comparable surface hydrophobicity, the adsorption uptake correlates strongly with the extent of protein under-wrapping [19]. As an adequate control, only proteins with the same extent of surface hydrophobicity or solvent-exposed nonpolar area were included in the comparative analysis. Hence, the attractive drag exerted by dehydrons on test hydrophobes became accessible. The net gain in Coulomb energy associated with wrapping a dehydron has been experimentally determined to be 4 kJ/mol [19]. The adhesive force exerted by a dehydron on a hydrophobe at 6 A distance is 7.8 pN, a magnitude comparable to the hydrophobic attraction between two nonpolar moieties that frame unfavorable interfaces with water. 

Building on this analysis, we may quantify the net hydrophobicity r] of a hydrogen bond by taking into account the surface flux of the dehydronic field generated by the hydrogen bond. This field is given by w 1 (R) ( = volume of test hydrophobe). Thus, in accord with Gauss theorem we obtain 

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