title: ATP-dependent fructose uptake system in Deinococcus radiodurans.
abstract: The bacterial phosphoenolpyruvate (PEP)-dependent group translocation system (PTS) requires the presence of both membrane-bound and cytoplasmic components to phosphorylate and translocate sugar. Deinococcus radiodurans has a functional fruA gene coding for the membrane-bound components of the fructose-specific PTS. However, fruB gene coding for the fructose-specific cytosolic components of PTS is a pseudogene. Yet, this bacterium metabolized fructose readily. In vitro studies showed that both cell membranes and cytoplasmic fractions of the cells were needed for fructose phosphorylation. Further studies showed that fructose phosphorylation required ATP, not PEP, as the phosphate donor. Unlike most PEP-dependent PTS systems, fructose phosphorylation is sensitive to sodium fluoride, a kinase inhibitor. Fructose phosphorylation was also inhibited in the presence of antiserum against a kinase phosphorylation site. Rhodobacter capsulatus has a functional fruA-fruB system. Complementation assays by reconstituting the membrane fraction of D. radiodurans to the cytoplasmic fraction of R. capsulatus resulted in a PEP-dependent fructose phosphorylation, whereas mixing the membranes of R. capsulatus and the deinococcal cytosol in vitro resulted in an ATP-dependent fructose phosphorylation.
authors.affiliation: Department of Biological Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan, Republic of China.
authors.forename: Hui-Yu
authors.initials: HY
authors.lastname: Lee
authors.forename: Minoti
authors.initials: M
authors.lastname: Magotra
authors.forename: Tit-Yee
authors.initials: TY
authors.lastname: Wong
authors.forename: Chiranjib
authors.initials: C
authors.lastname: Chakraborty
authors.forename: Jong-Kang
authors.initials: JK
authors.lastname: Liu
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism*; D034301:Deinococcus / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D005632:Fructose / Q000378:metabolism*; D017353:Gene Deletion; D005798:Genes, Bacterial; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System / Q000235:genetics / Q000378:metabolism*; D016354:Rhodobacter capsulatus / Q000235:genetics / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D005632:Fructose; D000255:Adenosine Triphosphate; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System