Understanding the Bridge H2O Concept in Protein Hydration

Bridge H₂O refers to a water molecule that forms a hydrogen-bonded bridge between two neighboring hydrogen bonds in a protein's hydration shell.

Effect on Protein Hydration

This bridging water molecule increases local proton (H⁺) and hydroxide (OH⁻) density, which can:

• Stabilize specific protein conformations
• Influence proton-transfer reactions
• Modulate the dielectric environment around charged residues

It is a concept used in computational biophysics and structural biology to describe fine details of protein–water interactions.