CHARACTERIZATION OF UDP AMINO-SUGARS AS MAJOR PHOSPHOCOMPOUNDS IN THEHYPERTHERMOPHILIC ARCHAEON PYROCOCCUS-FURIOSUS

The archaeon Pyrococcus furiosus is a strictly anaerobic heterotroph t hat grows optimally at 100 degrees C by the fermentation of carbohydra tes. It is known to contain high concentrations of novel intracellular solutes such as beta-mannosylglycerate and di-myo-inositol 1,1'-phosp hate (DIP) (L. O. Martins and H. Santos, Appl. Environ. Microbiol. 61: 3299-3303, 1995). Here, P-31 nuclear magnetic resonance (NMR) spectros copy was used to show that this organism also accumulates another type of phospho compound, as revealed by a major multiplet signal in the p yrophosphate region. The compounds were purified from cell extracts of P. furiosus by anion-exchange and gel filtration chromatographic proc edures and were structurally analyzed by H-1, C-13, and P-31 NMR spect roscopy. They were identified as two uridylated amino sugars, UDP N-ac etylglucosamine and UDP N-acetylgalactosamine. Unambiguous characteriz ations and complete assignments of H-1 and C-13 resonances from such s ugars have not been previously reported. In vitro P-31 NMR spectroscop ic analyses showed that, in contrast to DIP, which is maintained at a constant intracellular concentration (similar to 32 mM) throughout the growth phase of P. furiosus, the UDP amino sugars accumulated (to sim ilar to 14 mM) only during the late log phase. The possible biochemica l roles of these compounds in P. furiosus are discussed.