Multiscale Model for the Assembly Kinetics of Protein Complexes

Area of Science:

• Biochemistry and Molecular Biology
• Computational Biology
• Structural Biology

Background:

• Protein complex assembly is fundamental to cellular function, with misassembly leading to disease.
• Understanding the dynamic assembly mechanisms of protein complexes remains a significant challenge.
• Current research is shifting towards dynamic aspects beyond static quaternary structures.

Purpose of the Study:

• To develop a novel multiscale modeling framework for simulating protein complex assembly.
• To investigate the kinetics and thermodynamics of protein oligomerization and dimerization.
• To explore the diversity of assembly pathways and subunit binding interactions.

Main Methods:

• Developed a multiscale modeling framework combining rigid-body and Cα-based simulations.
• Applied the model to simulate the assembly of a homotrimer and a heterotetramer.
• Analyzed simulation data to determine assembly kinetics, thermodynamics, and pathway variations.

Main Results:

• Simulations revealed slower, multi-step assembly for oligomers compared to dimers, with greater thermodynamic stability.
• Demonstrated that diverse assembly pathways exist for the same quaternary structure, influenced by subunit binding constants.
• Showed synergistic strengthening of subunit binding during assembly, independent of allosteric effects or conformational changes.

Conclusions:

• The developed multiscale model provides a computationally efficient tool for studying protein complex assembly.
• The findings offer general principles governing protein complex formation, stability, and functional regulation.
• This work advances our understanding of the dynamic processes underlying biological complex formation.