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Published on: June 20, 2014
Modeling the microhydration of protonated alanine
Catherine Michaux1, Johan Wouters, Eric A Perpète
1Laboratoire de Chimie Biologique Structurale, Facultés Universitaires Notre-Dame de la Paix, rue de Bruxelles, 61, B-5000 Namur, Belgium.
The Journal of Physical Chemistry. B
|July 24, 2008
Summary
Protonated l-alanine microsolvation with water was studied. The research systematically mapped hydration stages, revealing key structural and energetic insights for protonated amino acid solvation.
Area of Science:
- Computational chemistry
- Physical chemistry
- Biochemistry
Background:
- Understanding amino acid solvation is crucial for biological processes.
- Protonated amino acids play significant roles in biological systems.
- Microsolvation studies provide insights into the initial hydration shells.
Purpose of the Study:
- To investigate the microsolvation of protonated l-alanine with 1-3 water molecules.
- To analyze the conformational landscape of hydrated protonated l-alanine.
- To establish a systematic approach for understanding stepwise hydration.
Main Methods:
- Ab initio calculations using MP2/6-311++G(d,p) level of theory.
- Full accounting for basis set superposition errors (BSSE).
- Conformational analysis and characterization of energy minima.
Main Results:
- Identified three stable conformers for unhydrated protonated l-alanine.
- Developed a logical tree illustrating successive hydration stages.
- Observed opposite effects on hydrogen-bond stretching with water addition to different solvation shells.
Conclusions:
- The computational approach accurately reproduces experimental thermodynamic data.
- Stepwise hydration of protonated l-alanine follows a systematic and related pattern.
- Multiple di- and trihydrated complexes likely coexist under experimental conditions.
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