Lysine120 interactions with p53 response elements can allosterically direct p53 organization.

Area of Science:

• Molecular Biology
• Genetics
• Biochemistry

Background:

• Transcription factors (TFs) like p53 bind to DNA response elements (REs) to regulate gene expression.
• p53-REs are diverse DNA sequences that can be located far from transcription start sites.
• Understanding how p53 distinguishes between similar p53-REs is crucial for comprehending selective gene regulation.

Purpose of the Study:

• To investigate how subtle DNA sequence variations in p53-REs influence p53 binding and selectivity.
• To elucidate the allosteric mechanisms by which DNA sequence dictates co-factor recruitment by p53.
• To explain how p53 achieves selective gene transactivation and diverse functional outcomes.

Main Methods:

• Molecular dynamics simulations of representative p53-REs in explicit solvent.
• Analysis of key residue interactions between p53 (Lys120, Arg280, Arg248) and DNA.
• Characterization of sequence-specific allosteric effects propagating through p53 and DNA.

Main Results:

• p53 exhibits unique interaction patterns with Lys120 specific to each p53-RE quarter site.
• DNA sequence-induced allosteric changes in Lys120 interactions are amplified by other p53-DNA interactions.
• These amplified allosteric effects alter p53 organization, surface topology, and residue fluctuations.

Conclusions:

• Subtle p53-RE sequence variations induce allosteric effects that dictate selective co-factor binding.
• This mechanism underlies p53's ability to discriminate between similar DNA sequences for specific gene transactivation.
• The findings provide insight into how p53 achieves diverse functional outcomes, including cell cycle arrest, DNA repair, and apoptosis.