Long-Range Water Ordering between Intrinsically Disordered Proteins and Its Impact on Protein Diffusion.

Area of Science:

• Biophysics
• Molecular Biology
• Soft Matter Physics

Background:

• Intrinsically disordered proteins (IDPs) are crucial for forming membraneless organelles.
• IDP diffusion dynamics influence condensate stability, phase separation, and molecular recognition.

Purpose of the Study:

• To investigate the diffusion dynamics of LAF-1 RGG domains.
• To explore the interplay between IDPs and their solvent environment.

Main Methods:

• Molecular dynamics simulations were used.
• Diffusion dynamics of IDPs and water molecules were analyzed.

Main Results:

• IDPs significantly enhance structural ordering of water molecules between them.
• This ordering slows down water diffusion, creating an effect similar to an 18 K solvent cooling.
• Increased effective viscosity around IDPs hinders their diffusion, even without interchain contacts.

Conclusions:

• IDPs profoundly influence the surrounding water structure and dynamics.
• The observed water ordering and diffusion slowdown contribute to increased effective viscosity, impacting IDP behavior.
• These findings offer insights into the physical mechanisms governing membraneless organelle formation and function.