mRNA display selection of a high-affinity, Bcl-X(L)-specific binding peptide.
Bcl-X(L), an antiapoptotic member of the Bcl-2 family, is a mitochondrial protein that inhibits activation of Bax and Bak, which commit the cell to apoptosis, and it therefore represents a potential target for drug discovery. Peptides have potential as therapeutic molecules because they can be designed to engage a larger portion of the target protein with higher specificity. In the present study, we selected 16-mer peptides that interact with Bcl-X(L) from random and degenerate peptide libraries using mRNA display. The selected peptides have sequence similarity with the Bcl-2 family BH3 domains, and one of them has higher affinity (IC(50)=0.9 microM) than Bak BH3 (IC(50)=11.8 microM) for Bcl-X(L) in vitro. We also found that GFP fusions of the selected peptides specifically interact with Bcl-X(L), localize in mitochondria, and induce cell death. Further, a chimeric molecule, in which the BH3 domain of Bak protein was replaced with a selected peptide, retained the ability to bind specifically to Bcl-X(L). These results demonstrate that this selected peptide specifically antagonizes the function of Bcl-X(L) and overcomes the effects of Bcl-X(L) in intact cells. We suggest that mRNA display is a powerful technique to identify peptide inhibitors with high affinity and specificity for disease-related proteins.
Matsumura
Nobutaka
N
Department of Biosciences and Informatics, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan.
Tsuji
Toru
T
Sumida
Takeshi
T
Kokubo
Masahito
M
Onimaru
Michiko
M
Doi
Nobuhide
N
Takashima
Hideaki
H
Miyamoto-Sato
Etsuko
E
Yanagawa
Hiroshi
H
D016923:Cell Death / Q000187:drug effects; D015723:Gene Library; D006801:Humans; D008928:Mitochondria; D019151:Peptide Library; D010455:Peptides / Q000378:metabolism / Q000494:pharmacology*; D011485:Protein Binding; D012333:RNA, Messenger; D051020:bcl-X Protein / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism
D019151:Peptide Library; D010455:Peptides; D012333:RNA, Messenger; D051020:bcl-X Protein