An empirical relationship between rotational correlation time and solvent accessible surface area.

Area of Science:

• Biophysics
• Structural Biology
• Computational Biology

Background:

• Protein structure and dynamics are crucial for biological function.
• Understanding the interplay between a protein's physical structure and its dynamic behavior is key.
• Empirical relationships can provide insights into these complex interrelationships.

Purpose of the Study:

• To investigate the empirical relationship between rotational correlation times (tau(c)) and solvent accessible surface areas (SASA).
• To evaluate the theoretical correlation between SASA and tau(c) using the equation SASA = K(r)tau(c)((2/3)).
• To compare calculated and experimental tau(c) values with SASA.

Main Methods:

• Determined Solvent Accessible Surface Area (SASA) from known protein structures.
• Calculated rotational correlation times (tau(c) calc) using diffusion tensor calculations.
• Measured experimental rotational correlation times (tau(c) expt) via NMR backbone (13)C or (15)N relaxation rate measurements.

Main Results:

• A strong correlation was observed between theoretical tau(c) and SASA (regression coefficient K(r) = 1696 m(2)s(-(2/3)), correlation coefficient = 0.92).
• Experimental tau(c) also correlated with SASA (regression coefficient K(r) = 1896 m(2)s(-(2/3)), correlation coefficient = 0.70).
• Both theoretical and experimental data support the relationship between protein size/dynamics and SASA.

Conclusions:

• The study empirically validates the relationship between protein dynamics (tau(c)) and solvent accessible surface area (SASA).
• These findings contribute to a better understanding of structure-dynamics-function relationships in proteins.
• The established correlation provides a valuable tool for predicting protein dynamics from structural data.