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BP: Fachverband Biologische Physik

BP 20: Protein Structure and Dynamics

BP 20.4: Hauptvortrag

Mittwoch, 11. März 2026, 15:45–16:15, BAR/0106

Solution scattering and MD simulation as quantitative probes of protein-specific and temperature-dependent hydration — •Jochen S Hub — Saarland University, Saarbrücken, Germany

The hydration shell is an integral part of proteins since it plays key roles for confor- mational transitions, molecular recognition, and enzymatic activity. While the dynam- ics of the hydration shell have been described in detail by spectroscopic techniques, the structure of the hydration shell remain less understood due to the lack of hydration shell-sensitive structural probes with high spatial resolution. Whether MD simulations correctly reproduce the hydration shell structure is not known. Small-angle scattering (SAS) with X-rays or neutrons (SAXS/SANS) is sensitive to the hydration shell; however, the hydration shell effects on SAS data has traditionally been considered as a problem, which had to be absorbed into free fitting parameters, rather than a chance to learn the hydration shell structure. We combine SAS data with MD simulations and explicit-solvent SAS predictions to reveal how factors such as surface properties, temperature, and force fields influence protein hydration. We find that (i) MD simulations with certain (but not all) force fields yield excellent agreement with the SAS data; (ii) chemical characteristics of surface-exposed moieties strongly modulate the hydration shell contrast and structure; (iii) temprature-ramp SAXS and MD show consistently that the protein hydration shell is remarkably temperature-sensitive. Our studies demonstrate the combination of SAS and explicit-solvent MD simulations as quantitative structural probes of protein hydation.

Keywords: Protein hydration shell; Small-angle scattering; MD simulations; Explicit-solvent SAXS/SANS predictions