β-Hairpins as peptidomimetics of human phosphoprotein-binding domains

Area of Science:

• Biochemistry and Molecular Biology
• Structural Biology
• Cancer Research

Background:

• Phosphoprotein-binding domains are crucial for biological processes, and their dysfunction is linked to diseases like cancer.
• The BRCA1 C-terminal (BRCT) domain plays a key role in DNA damage response signaling networks.
• Identifying BRCT-binding proteins can aid in developing diagnostics for abnormal phosphorylation-related diseases.

Purpose of the Study:

• To design and validate cyclic β-hairpin peptidomimetics that selectively bind to phosphorylated targets, specifically mimicking the BRCT domain.
• To explore the potential of these peptidomimetics as novel affinity reagents for molecular capture and identification.

Main Methods:

• In silico design of cyclic β-hairpin structures based on identified BRCT-phosphopeptide interaction residues and constraints.
• Virtual screening of designed cyclic peptide models for binding affinity and selectivity against target phosphopeptides.
• Synthesis, purification, and characterization of selected lead cyclic peptides.
• Experimental validation of high-affinity and selective binding to the target phosphopeptide and demonstration of capture via affinity chromatography.

Main Results:

• Designed cyclic β-hairpin structures effectively act as peptidomimetics of the BRCT domain.
• High selectivity and affinity were achieved for binding to a specific phosphorylated peptide (GK14-P).
• The lead cyclic peptide demonstrated successful capture of the target phosphopeptide using affinity chromatography.

Conclusions:

• Cyclic β-hairpin peptidomimetics represent a promising new class of affinity reagents.
• These reagents offer highly selective identification and capture of target molecules, with potential applications in diagnostics for phosphorylation-related diseases.