Cryo-EM Structure of Recombinantly Expressed hUGDH Unveils a Hidden, Alternative Allosteric Inhibitor

• DOI: 10.1021/acs.biochem.4c00555
• Publication Date: 2024-12-16T21:25:02Z
• Authors: John H. O’Brien; Renuka Kadirvelraj; Po-Sen Tseng; Nolan Ross-Kemppinen; David Crich; Richard M. Walsh; Zachary A. Wood
• Keywords: Random hexamer

Human UDP-glucose dehydrogenase (hUGDH) catalyzes the oxidation of into UDP-glucuronic acid, an essential substrate in Phase II metabolism drugs. hUGDH is a hexamer that exists equilibrium between active (E) state and inactive (EΩ) state, with latter being stabilized by binding allosteric inhibitor UDP-xylose (UDP-Xyl). The transition EΩ E slow can be observed as lag progress curves. Previous analysis suggested unliganded mainly EΩ, but two unique crystal forms suggest enzyme favors state. Resolving this discrepancy necessary to fully understand mechanism hUGDH. Here, we used cryo-EM show recombinant expressed Escherichia coli copurifies UDP-4-keto-xylose (UX4O), which mimics UDP-Xyl Cryo-EM studies removing UX4O from shifts ensemble favor This shift consistent curve analysis, shows absence for Inhibition has similar affinities UX4O. discovery inhibits suggests may physiologically relevant UGDHs bacteria do not make UDP-Xyl.