Inhibiting Hexamer Disassembly of Human UDP-Glucose Dehydrogenase by Photoactivated Amino Acid Cross-Linking.

ABSTRACT: The enzyme UDP-glucose dehydrogenase (UGDH) catalyzes the reaction of UDP-glucose to UDP-glucuronate through two successive NAD(+)-dependent oxidation steps. Human UGDH apoprotein is purified as a mixture of dimeric and hexameric species. Addition of substrate and cofactor stabilizes the oligomeric state to primarily the hexameric form. To determine if the dynamic conformations of hUGDH are required for catalytic activity, we used site-specific unnatural amino acid incorporation to facilitate cross-linking of monomeric subunits into predominantly obligate oligomeric species. Optimal cross-linking was achieved by encoding p-benzoyl-l-phenylalanine at position 458, normally a glutamine located within the dimer-dimer interface, and exposing the enzyme to long wavelength ultraviolet (UV) radia

SUBMITTER: Grady G 

PROVIDER: S-EPMC4955856 | biostudies-literature | 2016 Jun

REPOSITORIES: biostudies-literature