Green tea is already considered one of the world’s healthiest beverages, so much so that its components are frequently standardized and used in supplements and research.
One compound in particular, epigallocatechin gallate (EGCG), is often the focus of studies for its effect on cancer cell formation and tumor suppression. But even with that attention, the exact mechanics – the why – of its actions remained a mystery. Now, some of that mystery appears to be solved.
Researchers have found that EGCG from green tea promotes levels of one of the body’s natural anti-cancer proteins called “p53.” When it functions properly, p53 repairs DNA and stops tumors from progressing. But when this protein is damaged in some way, or levels are low, the improper cellular replication that allows tumors goes unchecked. Because p53 proteins are constantly in demand, they sustain a lot of wear and tear, which attracts further damage. Fortunately, EGCG essentially “repairs the repairer” by binding to the exact location of p53 that would otherwise suffer from further erosion by another protein called MDM2. By running interference like this, EGCG preserves valuable levels of p53, so there’s more available to stop tumor formation.
Zhao J, Blayney A, Liu X. et al. EGCG binds intrinsically disordered N-terminal domain of p53 and disrupts p53-MDM2 interaction. Nat Commun. 12, 986 (2021).
Epigallocatechin gallate (EGCG) from green tea can induce apoptosis in cancerous cells, but the underlying molecular mechanisms remain poorly understood. Using SPR and NMR, here we report a direct, μM interaction between EGCG and the tumor suppressor p53 (KD = 1.6 ± 1.4 μM), with the disordered N-terminal domain (NTD) identified as the major binding site (KD = 4 ± 2 μM). Large scale atomistic simulations (>100 μs), SAXS and AUC demonstrate that EGCG-NTD interaction is dynamic and EGCG causes the emergence of a subpopulation of compact bound conformations. The EGCG-p53 interaction disrupts p53 interaction with its regulatory E3 ligase MDM2 and inhibits ubiquitination of p53 by MDM2 in an in vitro ubiquitination assay, likely stabilizing p53 for anti-tumor activity. Our work provides insights into the mechanisms for EGCG’s anticancer activity and identifies p53 NTD as a target for cancer drug discovery through dynamic interactions with small molecules.
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