Multivalent site-specific phage modification enhances the binding affinity of receptor ligands

Area of Science:

• Biotechnology
• Chemical Biology
• Drug Discovery

Background:

• Combinatorial chemical libraries are crucial for identifying targeted molecules.
• Phage display technology enables rapid screening of vast peptide libraries for specific binding properties.
• Site-specific incorporation of non-canonical amino acids like selenocysteine (Sec) into phage-displayed peptides offers novel derivatization strategies.

Purpose of the Study:

• To demonstrate the utility of selectively derivatizing Sec residues on phage-displayed peptides with small molecules.
• To investigate the therapeutic potential of modified phage particles in targeting specific cellular receptors and pathways.
• To establish a proof-of-concept for hybrid small molecule-peptide libraries for phage-drug therapies.

Main Methods:

• Engineered M13 phage to display peptides with site-specifically inserted selenocysteine (Sec) residues.
• Developed a method for selective chemical modification of Sec residues with small molecule agonists targeting the adenosine A1 receptor.
• Assessed the binding affinity and downstream signaling potency of modified phage particles on cells expressing the target receptor.

Main Results:

• Successfully achieved site-specific derivatization of Sec residues on phage-displayed peptides with small molecule agonists.
• Demonstrated that modified Sec-phage particles exhibit significantly enhanced potency in binding to target cells and eliciting downstream signaling compared to unconjugated agonists.
• Showcased that other phage coat proteins, including pVIII, remained unmodified during the derivatization process.

Conclusions:

• The developed system enables the creation of hybrid small molecule-containing peptide libraries displayed on phage.
• This approach offers a powerful platform for developing novel phage-drug therapies with enhanced potency and specificity.
• The findings open new possibilities for targeted drug delivery and therapeutic applications using engineered bacteriophages.