5-FAM-PMDM6

Product Name: 5-FAM-PMDM6

Sequence One Letter Code: 5-FAM-(ß-A)-(ß-A)-FM-Aib-pY-(6-Cl-DL-Trp)-E-Ac3c-LN-NH2

Sequence Three Letter Code: 5-FAM-ß-Ala-ß-Ala-Phe-Met-*Aib-pTyr-(*6-Cl-DL-Trp)-Glu-*Ac3c-Leu-Asn-NH2 (*Aib: a-aminoisobutyric acid; *6-CI-DL-Trp: 6-chloro-DL-tryptoptophan; *Ac3c: 1-amino-cyclopropanecarboxylic acid)

Molecular Weight: 1784.3

Purity: 95%

Form: Lyophilized

Storage Conditions: - 20 °C Protected from light

Research Area: Cancer Disease Research

Conjugation: Conjugated

Conjugation Type: Fluorescent dyes

Code Nacres: NA.26

Application: 5-FAM-PMDM6 is a fluorescently labeled peptide probe designed to measure binding to MDM2, a negative regulator of the tumor suppressor p53. The FAM fluorophore enables sensitive fluorescence-based detection in competitive binding and inhibitor screening assays. This probe is widely used to evaluate compounds that disrupt the p53–MDM2 interaction, a key therapeutic target in oncology. It supports cancer research, drug discovery efforts, and studies focused on restoring p53-mediated tumor suppressor activity.

Current Research: The p53 tumor suppressor is a central regulator of cell cycle arrest, DNA repair, senescence, and apoptosis in response to cellular stress. In many cancers retaining wild-type p53, its activity is suppressed by overexpression of murine double minute 2 (MDM2), an E3 ubiquitin ligase that binds the N-terminal transactivation domain of p53 and targets it for proteasomal degradation. Disruption of the p53–MDM2 interaction has therefore emerged as a validated therapeutic strategy for restoring tumor suppressor function. 5-FAM-PMDM6 is a fluorescently labeled peptide probe designed to bind MDM2 and enable quantitative measurement of this critical protein–protein interaction. The PMDM6 peptide sequence is derived from the p53 transactivation domain and contains the key hydrophobic residues that mediate high-affinity binding to the MDM2 binding pocket. Structural studies have established that p53 engages MDM2 through an α-helical motif in which residues Phe19, Trp23, and Leu26 insert into a hydrophobic cleft on MDM2. PMDM6 recapitulates this interaction interface in a synthetic peptide format. Conjugation of a 5-carboxyfluorescein (5-FAM) fluorophore allows sensitive fluorescence-based detection of binding events without altering the essential interaction motif. 5-FAM-PMDM6 is widely used in fluorescence polarization (FP) assays to quantify MDM2 binding affinity. In this format, the fluorescent peptide exhibits increased polarization upon binding to recombinant MDM2 due to reduced rotational mobility. Competitive displacement by small-molecule inhibitors decreases polarization signal, providing a direct and quantitative readout of compound potency. This assay design is particularly suited for high-throughput screening of libraries targeting the p53–MDM2 interaction. The probe supports determination of equilibrium binding constants (Kd) between PMDM6 and MDM2, enabling comparative analysis of wild-type and mutant proteins. It also facilitates evaluation of structure–activity relationships (SAR) for candidate inhibitors. By measuring dose-dependent displacement of the fluorescent peptide, researchers can calculate IC50 and Ki values, guiding medicinal chemistry optimization. Because the assay directly interrogates the binding interface, it provides mechanistic clarity regarding competitive versus noncompetitive inhibition. In addition to screening applications, 5-FAM-PMDM6 contributes to mechanistic studies of p53 regulation. For example, researchers can assess how post-translational modifications or alternative MDM2 splice variants influence peptide binding. The probe also enables investigation of related interactions involving MDMX (MDM4), another negative regulator of p53 with structural similarity to MDM2. Comparative binding analyses help clarify selectivity profiles of therapeutic candidates. The fluorescent labeling strategy offers several practical advantages. The 5-FAM fluorophore provides strong excitation and emission properties compatible with standard fluorescence detection platforms, enabling robust signal generation and reproducibility. The non-radioactive format enhances safety and scalability for drug discovery workflows. Moreover, fluorescence-based assays allow real-time monitoring of binding equilibria and kinetic analysis under controlled conditions. Restoration of p53 activity through inhibition of MDM2 has yielded clinically approved agents and continues to drive oncology research. 5-FAM-PMDM6 plays a central role in these efforts by serving as a validated reference probe for assay development and compound validation. Its defined sequence ensures reproducible binding characteristics, supporting cross-study comparisons and assay standardization. In summary, 5-FAM-PMDM6 is a fluorescent peptide probe that models the p53–MDM2 interaction and enables quantitative fluorescence-based measurement of binding and competitive inhibition. Widely used in cancer research and drug discovery, it facilitates identification and characterization of compounds aimed at reactivating p53-mediated tumor suppressor pathways.