Solvent interactions and protein dynamics in spin-labeled T4 lysozyme

Area of Science:

• Biophysics
• Protein Dynamics
• Computational Biology

Background:

• T4 lysozyme dynamics and solvent interactions are crucial for its function.
• Previous electronic paramagnetic resonance (EPR) experiments showed differing mobilities in spin-labeled mutants (T4L-N40C and T4L-K48C).

Purpose of the Study:

• Investigate T4 lysozyme dynamics and solvent interactions using detailed simulations.
• Analyze spin label-solvent interactions and their effect on EPR lineshapes.
• Understand the impact of backbone motions on water density profiles.

Main Methods:

• Atomically detailed Molecular Dynamics (MD) simulations.
• Analysis of two spin-labeled T4 lysozyme mutants (T4L-N40C and T4L-K48C).
• Essential Dynamics (ED) analysis for hinge-bending motion.

Main Results:

• Differences in solvent distribution and diffusion around spin labels and protein residues were observed.
• The N-terminus of helix B acts as a hinge, exhibiting significant flexibility.
• Backbone motions influence water density profiles around the protein.

Conclusions:

• MD simulations provide insights into T4 lysozyme's dynamic behavior and solvent interactions.
• The hinge region's flexibility is key to the protein's domain closure motion.
• Spin label-solvent interactions can influence EPR spectral data.