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Peptide Isomerization is Suppressed at the Air-Water Interface
Aditya N Singh1,2, David T Limmer1,2,3,4
1Department of Chemistry, University of California, Berkeley, California 94720, United States.
The Journal of Physical Chemistry Letters
|January 11, 2022
Summary
Alanine dipeptide prefers the air-water interface due to stabilizing interactions. Isomerization rates between its conformations are slower at the interface than in bulk water.
Area of Science:
- Physical Chemistry
- Computational Chemistry
- Biophysics
Background:
- The air-water interface influences molecular behavior.
- Understanding molecular conformational changes at interfaces is crucial.
Purpose of the Study:
- Investigate thermodynamics and kinetics of alanine dipeptide isomerization at the air-water interface.
- Determine the role of the interface in molecular dynamics.
Main Methods:
- Molecular dynamics simulations.
- Transition Path Sampling with an extended potential (TPS+U).
Main Results:
- Alanine dipeptide exhibits affinity for the air-water interface.
- Intramolecular interactions stabilize the dipeptide at the interface.
- Isomerization rate is suppressed by a factor of 3 at the interface compared to bulk.
- Solvent effects on intramolecular interactions differ at the interface.
Conclusions:
- The air-water interface thermodynamically favors alanine dipeptide.
- Kinetics of isomerization are significantly altered by the interface.
- Water's reduced effectiveness in mediating interactions near the interface impacts isomerization pathways.
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