Solvation of Biomolecules

Water as the ubiquitous solvent of biomolecular systems plays important roles for biological function, as biomolecules have evolved and optimized their specific functions under aqueous solvation conditions. However, beyond structure formation, as e.g. in protein folding or the self-assembly of amphiphilic molecules into higher-order structures such as bilayers or micelles, the precise role of water molecules for biomolecular function often remain enigmatic at the atomic level.

Recently, we investigated a prototypical peripheral membrane protein, annexin B12, and analyzed how exactly solvent properties are affected due to the presence of i) the lipid membrane, and ii) the protein itself (see Figure). Our molecular dynamics simulations enable one to relate changes in the dynamics of these water molecules, as experimentally derived from Overhauser dynamic nuclear polarization (ODNP)-enhanced NMR relaxometry, to thermodynamic properties that are not directly accessible to experiment, such as solvent entropy. The altered properties of the solvent could have implications for molecular recognition close to membrane interfaces, e.g., the formation of protein-protein complexes.