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Updated: Jul 12, 2026
08:48
High-Resolution Neutron Spectroscopy to Study Picosecond-Nanosecond Dynamics of Proteins and Hydration Water
Published on: April 28, 2022
Multi-Force-Field Molecular Dynamics Reveals How Cation Hydration Kinetics Dictate Polypeptide Assembly Pathways and
Lei Bao1, Ben-Chao Zhu1, Chenjie Feng2
1School of Public Health, Hubei University of Medicine, Shiyan 442000, China.
Journal of Chemical Theory and Computation
|July 9, 2026
Summary
Magnesium (Mg2+) and calcium (Ca2+) ions assemble biomolecules differently due to their distinct water-exchange rates. Mg2+ acts as a slow reorganizer, while Ca2+ rapidly triggers assembly, establishing a "hydration clock" model.
Area of Science:
- Biomolecular assembly
- Biophysical chemistry
- Computational biophysics
Background:
- Cation hydration dynamics influence biomolecular assembly.
- A quantitative link between cation water-exchange kinetics and assembly pathways is missing.
Purpose of the Study:
- Establish a quantitative, causal link between cation hydration kinetics and biomolecular assembly pathways.
- Investigate the distinct roles of Mg2+ and Ca2+ in assembly.
Main Methods:
- Multi-force-field all-atom molecular dynamics simulations.
- Enhanced sampling and Markov state model analysis.
- Comparison of force fields with varying hydration exchange rates, validated by NMR data.
Main Results:
- Mg2+ (microsecond water exchange) is a slow structural reorganizer, requiring stepwise dehydration for coordination and gradually disrupting salt bridges.
- Ca2+ (picosecond-to-nanosecond water exchange) is a fast microphase separation trigger, directly bridging aspartate residues.
- Established a causal chain from hydration kinetics to coordination to assembly timescales.
Conclusions:
- Proposed the "hydration clock" model where cation water-exchange kinetics dictate biomolecular assembly timescales.
- Provided a kinetic framework for understanding cation-specific effects in self-assembly.
- Enabled rational design of time-programmable self-assembling systems.
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