Variation in structure of a protein (H2AX) with knowledge-based interactions

Area of Science:

• Structural Biology
• Computational Biophysics
• Protein Dynamics

Background:

• Understanding protein structure-temperature relationships is crucial for predicting protein behavior in various biological environments.
• Knowledge-based potentials offer a framework for modeling protein interactions and conformational changes.

Purpose of the Study:

• To investigate the temperature-dependent structural changes of the H2AX protein using three distinct knowledge-based interaction models.
• To identify similarities and differences in protein structural responses across different interaction potentials (MJ, BT, BFKV).

Main Methods:

• Utilized three knowledge-based phenomenological interactions: Miyazawa and Jernigan (MJ), Betancourt and Thirumalai (BT), and Bastolla et al. (BFKV).
• Analyzed the radius of gyration (Rg) as a function of temperature for the H2AX protein.
• Examined the scaling of the structure factor with the wave vector to characterize conformational states.

Main Results:

• The radius of gyration (Rg) of H2AX exhibits a non-monotonic dependence on temperature, increasing and then decreasing.
• A characteristic temperature (Tc) for this non-monotonic behavior varies with the interaction matrix: TcBFKV ≤ TcMJ ≤ TcBT.
• The temperature range (ΔT) and decay pattern of the non-monotonic response are sensitive to the specific interaction used, with significant variations observed between MJ, BT, and BFKV interactions.

Conclusions:

• The study confirms that protein structure, specifically H2AX, undergoes significant conformational changes with temperature, transitioning from a random coil at high temperatures to a globular state at low temperatures.
• The choice of knowledge-based interaction model significantly influences the quantitative details of the temperature-dependent structural response, including the characteristic temperature and the range of non-monotonic behavior.