Structural Characterization of the Aurora Kinase B "DFG-flip" Using Metadynamics

Area of Science:

• Biochemistry
• Structural Biology
• Computational Chemistry

Background:

• Aurora kinase B (AKB) is a key mitotic regulator overexpressed in cancers.
• Current AKB inhibitors target the active DFG "in" conformation.
• Type II inhibitors offer improved selectivity and potency but require the inactive DFG "out" conformation, which is uncharacterized for AKB.

Purpose of the Study:

• To computationally determine the inactive DFG "out" conformation of Aurora kinase B (AKB).
• To identify key interactions stabilizing active and inactive AKB states.
• To explore novel inhibitor design strategies targeting AKB conformations.

Main Methods:

• Atomistic molecular dynamics (MD) simulations, specifically using the metadynamics (MTD) approach.
• Simulation of the DFG "out" conformation from the experimentally determined DFG "in" state.
• Analysis of structural changes and stabilizing interactions during the DFG-flip.

Main Results:

• Successfully simulated the DFG "out" conformation of AKB, providing structural insights into its inactive state.
• Identified critical interactions responsible for stabilizing both active (DFG "in") and inactive (DFG "out") conformations.
• Discovered a unique "DFG up" transition state, a potential target for novel inhibitors.

Conclusions:

• Metadynamics simulations are effective for predicting macromolecular conformational changes at lower computational cost.
• Structural understanding of AKB's inactive and transition states is crucial for next-generation inhibitor design.
• This study provides a foundation for developing more selective and potent AKB-targeted cancer therapies.