Deciphering the Mystery in p300 Taz2-p53 TAD2 Recognition.

Area of Science:

• Biochemistry
• Structural Biology
• Computational Biology

Background:

• Intrinsically disordered proteins (IDPs) are vital for cellular signaling, exhibiting low-affinity, high-specificity binding.
• The transcription factor p53, a tumor suppressor, utilizes disordered regions like p53 TAD2 for its functions.
• Understanding IDP binding mechanisms is challenging due to their dynamic nature.

Purpose of the Study:

• To investigate the binding mechanism between p300 Taz2 and p53 TAD2 using computational simulations.
• To elucidate the role of specific structural features and intermediate states in the binding process.

Main Methods:

• Extensive molecular dynamics (MD) simulations employing the UNRES force field with Go̅-like potentials.
• Utilized NMR-derived distance restraints to guide and accelerate binding simulations.
• Applied machine learning (PathDetect-SOM) to identify binding pathways and intermediate states.

Main Results:

• Identified a metastable intermediate state where the p53 TAD2 helix anchors in the p300 Taz2 binding pocket.
• Characterized a multi-stage binding process: encounter complex formation, partial attachment, and final binding.
• Discovered two distinct binding pathways involving encounter and intermediate states.

Conclusions:

• The helical segment of p53 TAD2 plays a critical role in directing specific binding to p300 Taz2.
• MD simulations provide valuable insights into the complex binding dynamics of IDPs.
• This study enhances understanding of p53's role in cancer suppression through its interaction with p300.