From mutational inactivation to aberrant gain-of-function: Unraveling the structural basis of mutant p53 oncogenic

Fisayo A Olotu1, Mahmoud E S Soliman1,2,3

  • 1Molecular Modeling and Drug Design Research Group, School of Health Sciences, University of KwaZulu-Natal, Westville Campus, Durban, South Africa.

Insights

Mutant p53 gain-of-function (GOF) involves structural changes beyond inactivation. This study reveals how mutations alter p53 structure, exposing binding sites crucial for cancer, offering new therapeutic targets.

Area of Science:

  • Molecular Biology
  • Structural Biology
  • Oncology

Background:

  • Mutations in the p53 gene can lead to a gain-of-function (GOF), promoting cancer beyond simple inactivation of its tumor-suppressive role.
  • Understanding the structural dynamics of mutant p53 (mutp53) is crucial for developing targeted therapies.

Purpose of the Study:

  • To investigate the dynamic structural transitions of wildtype (WT) p53 and common mutp53 variants (R273C, R175H) into a GOF state.
  • To elucidate the conformational changes underlying mutp53 GOF activities and identify potential therapeutic targets.

Main Methods:

  • Utilized molecular dynamics simulations to study the structural dynamics of WT p53, R273C mutp53, and R175H mutp53.
  • Analyzed structural distortion, flexibility, accessible surface area, and binding cavities in both WT and mutant p53 forms.

Main Results:

  • Mutant p53 forms exhibited structural distortion, reduced flexibility, increased rigidity, and enhanced kinetic stability compared to WT p53.
  • Increased accessible surface area in mutants suggests protein unfolding, exposing hydrophobic surfaces for interactions with HSF-1, p63, and p73.
  • Identified distinct binding cavities in mutants compared to WT p53, correlating with GOF interactions.

Conclusions:

  • Mutation-induced structural changes, including unfolding and exposure of binding surfaces, are key to mutp53 GOF activities.
  • These findings provide a structural basis for targeting mutp53's oncogenic functions, distinct from WT p53 inactivation.
  • The identified exposed binding sites offer opportunities for structure-based drug design to disrupt mutp53 GOF interactions.

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