Research Projects

Purine nucleotides are essential building blocks of DNA and RNA and serve as critical regulators of cellular energy and signaling. Their synthesis via the de novo purine biosynthetic pathway is tightly regulated, particularly in rapidly proliferating cells such as those found in cancer. One of the key enzymes in this pathway, FGAM synthetase (PurL), catalyzes a pivotal step in purine biosynthesis and has recently emerged as a metabolic vulnerability in hepatocellular carcinoma, making it a promising therapeutic target. This project focuses on unraveling the allosteric regulation and conformational dynamics in PurL, a large multidomain enzyme that facilitates ammonia transfer via a transient, substrate-induced tunnel. Our earlier unnatural fluorescent probe-based analysis, supported by insights from prior molecular simulation studies, highlight the role of a critical catalytic loop and suggest a finely orchestrated interdomain communication network driving this process. To investigate this, we propose a multidisciplinary approach integrating cryo-electron microscopy (cryo-EM) to resolve conformational states and capture the transient tunnel, single-molecule FRET to track interdomain dynamics, and ¹⁹F NMR to probe substrate-induced changes in tunnel interactions. Together, these insights will guide the development of allosteric inhibitors targeting dynamic interdomain interfaces, offering superior specificity and novel therapeutic strategies against liver cancer.