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Site Directed Spin Labeling and EPR Spectroscopic Studies of Pentameric Ligand-Gated Ion Channels
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Site Correlations, Capacitance, and Polarizability From Protein Protonation Fluctuations
Anže Božič1, Rudolf Podgornik2,3,4,5,6
1Department of Theoretical Physics, Jožef Stefan Institute, Ljubljana SI-1000, Slovenia.
The Journal of Physical Chemistry. B
|November 16, 2021
Summary
Protonation fluctuations in globular proteins are generalized using Kirkwood-Shumaker theory. Charge and dipole moment fluctuations depend on pH, impacting protein interactions in solution.
Area of Science:
- Biophysics
- Physical Chemistry
- Protein Science
Background:
- The Kirkwood-Shumaker theory describes interactions in solutions.
- Understanding protein charge fluctuations is crucial for biophysical studies.
- Anisotropic charge distributions on proteins present unique challenges.
Purpose of the Study:
- To generalize the Kirkwood-Shumaker theory for anisotropic charge distributions on globular proteins.
- To investigate the dependence of protein charge and dipole moment fluctuations on solution pH.
- To analyze the implications for Kirkwood-Shumaker interactions under varying solution conditions.
Main Methods:
- Generalization of the Kirkwood-Shumaker theory.
- Analysis of proton occupancy correlators for anisotropic charge distributions.
- Theoretical modeling of charge and dipole moment fluctuations.
Main Results:
- Fluctuations in total charge and dipole moment are linked to the same proton occupancy correlator.
- Both charge and dipole moment fluctuations exhibit a similar dependence on solution pH.
- This pH dependence contrasts with the behavior of average values.
Conclusions:
- The generalized theory provides new insights into protein electrostatics.
- Protonation fluctuations significantly influence protein interactions.
- Solution pH is a critical factor affecting protein behavior and interactions.
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