Disordered Motifs and Domains in Cell Control
Poster Session II
43-POS
Board 19
NMR Study of the Interaction between MDM2 and a Peptide Selected by mRNA Display
Takashi Nagata
1,2
, Kie Shirakawa
3
, Naohiro Kobayashi
4
, Hirokazu Shiheido
3
, Noriko Tabata
3
,
Yuko Sakuma-Yonemura
3
, Kenichi Horisawa
3
, Masato Katahira
1,2
, Nobuhide Doi
3
, Hiroshi
Yanagawa
3
.
1
Kyoto University, Uji, Japan,
3
Keio University, Yokohama, Japan,
2
Kyoto University, Uji,
Japan,
4
Osaka University, Suita, Japan.
OBJECTIVE: MDM2 is an oncoprotein who binds to the intrinsically disordered region (IDR) of
tumor suppressor p53 and inhibits its functions. p53 prevents tumorigenesis through cell cycle
arrest or apoptosis of cells in response to cellular stress such as DNA damage. Thus, inactivation
of p53 by MDM2 leads to the development of several human cancers. Peptides that mimic the
MDM2-binding region of p53-IDR reportedly restore the anti-cancer activity of the p53
pathway. We aimed to obtain the peptide that has a higher potency and affinity to MDM2 than
the known ones and elucidate the mechanism of the strong binding.
RESULTS: We screened for the MDM2-binding peptide from large random peptide libraries in
two stages by means of mRNA display. The obtained 12-mer peptide, which we named MIP,
exhibited higher affinity to MDM2 than the reported ones as confirmed by SPR. Experiments
using living cells showed that MIP has superior binding activity and potency to prevent tumor
cell growth. We have then determined the structure of MIP and MDM2 in the bound form by
solution NMR method.
CONCLUSIONS: Comparison between the structures of MIP:MDM2 complex and previously
reported p53 peptide:MDM2, DI:MDM2, and PMI:MDM2 complexes showed that the stronger
binding and higher anti-MDM2 activity observed for MIP can be explained as due to its enlarged
binding surface over previously reported peptides. Additionally, MIP was found to have
tendency to form some secondary structure in the hydrophobic solution environments. These
findings provide fruitful hints for drug discovery against diseases caused by abrogation of the
function of intrinsically disordered proteins.
- 95 -
