Hydrogen Bonds: Stickiness of the Hydrogen Bond (Ann. Phys. 9/2018)

Abstract

The dielectric response of bulk water follows laws of continuum electrostatics,a scheme often extrapolated without justification to treat confined interfacialwater, where the Debye polarization ansatz breaks down and discrete effectsmatter. Reconciling the discrete behavior with the continuum equationsrequires a conceptual leap, all the more so when assessing the electrostaticimpact of exclusion of individual water molecules. This work takes up thechallenge and identifies the nanoscale stickiness of a preformedwater-embedded hydrogen bond as phenomena not encompassed bycontinuum laws but quantitatively predictable when adopting a nanoscaletheory of dielectric response holding down to molecular dimensions.Nanoscale stickiness is known to drive basic cellular events and has beenmeasured using a molecular force probe but its physical underpinnings andcomputation have been lacking so far. The findings reported may impactmolecular design in bio-nanotechnology and shed light on standingchallenges in biophysics, especially on the protein folding problem, whereorganized compaction of the protein chain following nucleatingintramolecular hydrogen bonding demands explanation.