3eqy

Publication Abstract from PubMed

The oncoproteins MDM2 and MDMX negatively regulate the activity and stability of the tumor suppressor protein p53-a cellular process initiated by MDM2 and/or MDMX binding to the N-terminal transactivation domain of p53. MDM2 and MDMX in many tumors confer p53 inactivation and tumor survival, and are important molecular targets for anticancer therapy. We screened a duodecimal peptide phage library against site-specifically biotinylated p53-binding domains of human MDM2 and MDMX chemically synthesized via native chemical ligation, and identified several peptide inhibitors of the p53-MDM2/MDMX interactions. The most potent inhibitor (TSFAEYWNLLSP), termed PMI, bound to MDM2 and MDMX at low nanomolar affinities-approximately 2 orders of magnitude stronger than the wild-type p53 peptide of the same length (ETFSDLWKLLPE). We solved the crystal structures of synthetic MDM2 and MDMX, both in complex with PMI, at 1.6 A resolution. Comparative structural analysis identified an extensive, tightened intramolecular H-bonding network in bound PMI that contributed to its conformational stability, thus enhanced binding to the 2 oncogenic proteins. Importantly, the C-terminal residue Pro of PMI induced formation of a hydrophobic cleft in MDMX previously unseen in the structures of p53-bound MDM2 or MDMX. Our findings deciphered the structural basis for high-affinity peptide inhibition of p53 interactions with MDM2 and MDMX, shedding new light on structure-based rational design of different classes of p53 activators for potential therapeutic use.

Structural basis for high-affinity peptide inhibition of p53 interactions with MDM2 and MDMX.,Pazgier M, Liu M, Zou G, Yuan W, Li C, Li C, Li J, Monbo J, Zella D, Tarasov SG, Lu W Proc Natl Acad Sci U S A. 2009 Mar 2. PMID:19255450^[3]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.