BRCA1-derived peptide constructs exhibit sequence-dependent features compatible with modulation of the p53-MDM2 axis

Area of Science:

• Biochemistry
• Molecular Biology
• Drug Discovery

Background:

• The p53-MDM2 interaction regulates p53 protein stability and is a key target for restoring p53 function.
• Current peptide inhibitors often mimic the p53 transactivation domain's F-W-L hydrophobic motif.

Purpose of the Study:

• To investigate how hydrophobic motif composition and sequence context in BRCA1-derived peptides affect their binding to the MDM2 interface.
• To explore non-canonical peptide architectures for targeting the p53-MDM2 interaction.

Main Methods:

• Engineering BRCA1-derived peptides with varied hydrophobic motifs (including F-W-F).
• Evaluating peptides using molecular docking, molecular dynamics simulations, and cellular assays (HEK293T cells).
• Assessing peptide impact on p53 protein levels via EGFP-linker-peptide fusion constructs.

Main Results:

• Several BRCA1-derived peptides increased p53 protein levels, with pBR3 and pBR4 showing the highest efficacy.
• Peptides with non-canonical F-W-F motifs demonstrated greater activity than some with similar docking scores.
• Molecular dynamics confirmed sustained peptide association with the MDM2 binding cleft, despite different interaction patterns.

Conclusions:

• Hydrophobic motif composition and sequence context significantly influence the p53-MDM2 interaction.
• Alternative hydrophobic residue arrangements can be compatible with the MDM2 binding interface.
• Findings provide a basis for developing novel peptide inhibitors targeting the p53-MDM2 axis.