Screening of a library of phage-displayed peptides identifies human bcl-2 as a taxol-binding protein

• Published in: Journal of molecular biology Vol. 285; no. 1; pp. 197 - 203
• Main Authors: Rodi, D J, Janes, R W, Sanganee, H J, Holton, R A, Wallace, B A, Makowski, L
• Format: Journal Article
• Language: English
• Published: England 08.01.1999
• Subjects: Amino Acid Sequence; Antineoplastic Agents, Phytogenic - metabolism; Bacteriophages; Circular Dichroism; Consensus Sequence; Enzyme-Linked Immunosorbent Assay; Humans; Molecular Sequence Data; Paclitaxel - metabolism; Peptide Library; Proto-Oncogene Proteins c-bcl-2 - metabolism
• ISSN: 0022-2836
• DOI: 10.1006/jmbi.1998.2303

A random library of phage displayed peptides was screened for binding to a biotinylated derivative of paclitaxel (Taxol). Affinity-selected peptides were analyzed for similarity to human proteins. There was no significant similarity between the paclitaxel-selected peptides and tubulin. However, a subset of the peptides was identified that exhibits significant similarity to a non-conserved region of the anti-apoptotic human protein Bcl-2: ELISA assays confirmed binding of paclitaxel to Bcl-2, and circular dichroism spectroscopy demonstrated that a substantial conformational change accompanies this binding. In vivo, treatment with paclitaxel has been shown to lead to Bcl-2 inactivation with concomitant phosphorylation of residues in a disordered, regulatory loop region of the protein. Similarity between paclitaxel-selected peptides and this loop region implicate these residues in drug binding, and suggest that the apoptotic action of paclitaxel may involve the binding of paclitaxel to Bcl-2. These results demonstrate that peptides displayed on the surface of bacteriophage particles can mimic the ligand-binding properties of disordered regions of proteins.