Screening of a library of phage-displayed peptides identifies human bcl-2 as a taxol-binding protein.
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.
Rodi
D J
DJ
Institute of Molecular Biophysics, Florida State University, Tallahassee, FL, 32306, USA.
Janes
R W
RW
Sanganee
H J
HJ
Holton
R A
RA
Wallace
B A
BA
Makowski
L
L
D000595:Amino Acid Sequence; D000972:Antineoplastic Agents, Phytogenic / Q000378:metabolism*; D001435:Bacteriophages; D002942:Circular Dichroism; D016384:Consensus Sequence; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D008969:Molecular Sequence Data; D017239:Paclitaxel / Q000378:metabolism*; D019151:Peptide Library; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism*
D000972:Antineoplastic Agents, Phytogenic; D019151:Peptide Library; D019253:Proto-Oncogene Proteins c-bcl-2; D017239:Paclitaxel