Phage Display
A laboratory technique in which peptide sequences are expressed on the surface of bacteriophage (virus) particles, allowing researchers to screen vast libraries of peptide variants for binding to a target of interest. Phage display is widely used in peptide drug discovery and was recognised with the 2018 Nobel Prize in Chemistry.
Technical Context
In phage display, synthetic DNA encoding random peptide sequences is inserted into the gene for a bacteriophage coat protein (typically pIII or pVIII of M13 phage). Each phage particle displays a unique peptide on its surface while carrying the encoding DNA internally. The library (typically 10^8-10^10 variants) is screened by exposing phages to an immobilised target — those that bind are retained, amplified, and reselected over multiple rounds (biopanning). DNA sequencing identifies the winning peptide sequences. George Smith and Sir Gregory Winter shared the 2018 Nobel Prize in Chemistry for phage display technology. It has been used to discover peptide drug leads and antibody therapeutics.