Molecular dynamics study of interactions between polymorphic actin filaments and gelsolin segment-1

Area of Science:

• Biochemistry
• Molecular Biology
• Biophysics

Background:

• Actin filaments are crucial for eukaryotic cellular processes.
• Actin-binding proteins (ABPs) regulate actin dynamics.
• Actin filaments exhibit structural polymorphism, potentially affecting ABP interactions.

Purpose of the Study:

• To investigate how actin filament structural polymorphism influences the interaction of gelsolin segment 1 (S1) with the filament barbed-end.
• To understand the molecular basis of gelsolin-actin interactions in polymorphic states.

Main Methods:

• All-atom molecular dynamics simulations were employed.
• Analysis focused on the interface between gelsolin S1 and the actin filament barbed-end.

Main Results:

• Different tilted states of actin subunits modulate gelsolin S1 interactions.
• Hydrogen bonding and interaction energy revealed distinct barbed-end conformations.
• These conformational differences lead to varied gelsolin S1 interactions.

Conclusions:

• Actin filament structural multiplicity plays a significant role in interactions with actin-binding proteins like gelsolin.
• Understanding these polymorphic interactions is key to comprehending actin-based cellular regulation.