Complementarity of structure ensembles in protein-protein binding

Area of Science:

• Structural Biology
• Computational Biology
• Biophysics

Background:

• Protein-protein interactions are crucial for cellular functions.
• Predicting protein complex structures is challenging due to protein flexibility.
• Existing models do not fully explain the dynamics of protein binding.

Purpose of the Study:

• To investigate the role of protein flexibility in protein-protein recognition.
• To develop a more accurate model for predicting protein complex formation.
• To understand the mechanism underlying protein-protein association.

Main Methods:

• Performed molecular dynamics simulations on unbound receptor and ligand structures for 17 protein complexes.
• Applied shape-driven rigid body docking to representative snapshots from simulations.
• Utilized crossdocking of structure ensembles to enhance prediction accuracy.

Main Results:

• Crossdocking structure ensembles significantly improved the identification of near-native protein complex solutions.
• Unbound protein ensembles exhibited diverse conformations not present in bound states.
• These complementary conformations are key to successful protein recognition.

Conclusions:

• Protein-protein binding likely follows a three-step mechanism: diffusion, free conformer selection, and refolding.
• This proposed model integrates existing theories and aligns with experimental data on interaction kinetics and forces.
• The findings offer a new perspective on the dynamic nature of protein complex formation.