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Calculation of volume fluctuation for globular protein models.
Summary
Protein volume fluctuations are influenced by water, with surface tension playing a key role. This study quanties the impact of water on protein dynamics.
Area of Science:
- Biophysics
- Physical Chemistry
Background:
- Globular proteins exhibit volume fluctuations due to thermal motion.
- Surface tension is a critical factor influencing these fluctuations.
Purpose of the Study:
- To calculate the volume fluctuation extent for protein models.
- To compare calculated values with experimental compressibility measurements.
- To investigate the role of solvent water in protein volume fluctuations.
Main Methods:
- Utilized two geometrical models for globular proteins.
- Applied a potential proportional to the surface area generated by thermal motion.
- Compared calculated values with experimental compressibility data, including hydration correction.
Main Results:
- Calculated volume fluctuation values were obtained using surface tension (gamma) values between 25 and 46 cal/mol/A2.
- Experimental values, after hydration correction, fell within this calculated range.
- The results align with independent estimates of interfacial tension between nonpolar molecules and water.
Conclusions:
- Solvent water significantly impacts the volume fluctuation extent of globular proteins.
- Interfacial tension concepts are relevant for understanding protein behavior in aqueous environments.
- The estimated interfacial tension values may have practical applications.