Peptides derived from the two regulatory domains of p53 are recognized by two p53-activating antibodies

Area of Science:

• Molecular Biology
• Protein Biochemistry
• Immunology

Background:

• The transcription factor p53 is crucial for DNA damage response.
• Both the N-terminus and C-terminus of p53 regulate its DNA-binding activity.
• Specific antibodies can modulate p53's regulatory functions.

Purpose of the Study:

• To investigate the epitopes recognized by p53-activating antibodies HR231 and Pab421.
• To determine if these antibodies interact with regulatory regions of p53.
• To understand the molecular basis of antibody-mediated p53 activation.

Main Methods:

• Phage display peptide library screening.
• Multiple peptide synthesis.
• Epitope mapping using antibody binding assays.

Main Results:

• Antibodies HR231 and Pab421 recognize peptides from the C-terminus of p53.
• These antibodies also recognize peptides from the N-terminus of p53.
• The recognized peptide sequences map to known negative regulatory regions of p53, suggesting a conformational epitope.

Conclusions:

• Antibodies HR231 and Pab421 bind to a conformational epitope involving both N- and C-terminal regulatory regions of p53.
• This binding explains the observed p53-activating activity of these antibodies.
• The findings provide a deeper understanding of p53 regulation and potential therapeutic targeting.