Publications

• Cloning of the sdsA gene encoding solanesyl diphosphate synthase from Rhodobacter capsulatus and its functional expression in Escherichia coli and Saccharomyces cerevisiae.

  Okada K., Kamiya Y., Zhu X., Suzuki K., Tanaka K., Nakagawa T., Matsuda H., Kawamukai M.

  Different organisms produce different species of isoprenoid quinones, each with its own distinctive length. These differences in length are commonly exploited in microbial classification. The side chain length of quinone is determined by the nature of the polyprenyl diphosphate synthase that catal ... >> More

  Different organisms produce different species of isoprenoid quinones, each with its own distinctive length. These differences in length are commonly exploited in microbial classification. The side chain length of quinone is determined by the nature of the polyprenyl diphosphate synthase that catalyzes the reaction. To determine if the side chain length of ubiquinone (UQ) has any distinct role to play in the metabolism of the cells in which it is found, we cloned the solanesyl diphosphate synthase gene (sdsA) from Rhodobacter capsulatus SB1003 and expressed it in Escherichia coli and Saccharomyces cerevisiae. Sequence analysis revealed that the sdsA gene encodes a 325-amino-acid protein which has similarity (27 to 40%) with other prenyl diphosphate synthases. Expression of the sdsA gene complemented a defect in the octaprenyl diphosphate synthase gene of E. coli and the nonrespiratory phenotype resulting from a defect in the hexaprenyl diphosphate synthase gene of S. cerevisiae. Both E. coli and S. cerevisiae expressing the sdsA gene mainly produced solanesyl diphosphate, which resulted in the synthesis of UQ-9 without any noticeable effect on the growth of the cells. Thus, it appears that UQ-9 can replace the function of UQ-8 in E. coli and UQ-6 in S. cerevisiae. Taken together with previous results, the results described here imply that the side chain length of UQ is not a critical factor for the survival of microorganisms. << Less

  J. Bacteriol. 179:5992-5998(1997) [PubMed] [EuropePMC]

• Farnesyl diphosphate synthase and solanesyl diphosphate synthase reactions of diphosphate-modified allylic analogs: the significance of the diphosphate linkage involved in the allylic substrates for prenyltransferase.

  Gotoh T., Koyama T., Ogura K.

  Diphosphate-modified substrates for prenyltransferase were synthesized and examined as substrates for the prenyltransferase reaction. They were dimethylallyl methylenediphosphonate, geranyl methylenediphosphonate, geranyl imidodiphosphate, geranyl phosphosulfate, farnesyl methylenediphosphonate, f ... >> More

  Diphosphate-modified substrates for prenyltransferase were synthesized and examined as substrates for the prenyltransferase reaction. They were dimethylallyl methylenediphosphonate, geranyl methylenediphosphonate, geranyl imidodiphosphate, geranyl phosphosulfate, farnesyl methylenediphosphonate, farnesyl imidodiphosphate, and farnesyl phosphosulfate. All of them except dimethylallyl methylenediphosphonate were accepted as substrates by solanesyl diphosphate synthase to give solanesyl diphosphate and the former four analogs were also accepted as substrates by farnesyl diphosphate synthase to give farnesyl diphosphate. The Km values of both enzymes for the methylenediphosphonate and imidodiphosphate analogs were comparable to those of the corresponding diphosphate substrates, but the phosphosulfate analogs showed much greater Km values than the diphosphate substrates. On the other hand, the Vmax values for these artificial substrates were all smaller than those for the corresponding natural substrates. Kinetic experiments with the analogs showed that the ionization-condensation-elimination mechanism proposed for the farnesyl diphosphate synthase reaction holds also for the solanesyl diphosphate synthase reaction and that the diphosphoryl structure, capable of chelating with divalent cations, is important topologically and kinetically rather than thermodynamically. << Less

  J Biochem 112:20-27(1992) [PubMed] [EuropePMC]

• Purification of solanesyl-diphosphate synthase from Micrococcus luteus. A new class of prenyltransferase.

  Ohnuma S., Koyama T., Ogura K.

  The activity of solanesyl-diphosphate synthase from Micrococcus luteus is stimulated by a high molecular mass fraction (HMF) which is separated from cell-free extracts of the same bacterium by DEAE-Toyopearl chromatography followed by Sephadex G-100 chromatography. By employing HMF in the assay pr ... >> More

  The activity of solanesyl-diphosphate synthase from Micrococcus luteus is stimulated by a high molecular mass fraction (HMF) which is separated from cell-free extracts of the same bacterium by DEAE-Toyopearl chromatography followed by Sephadex G-100 chromatography. By employing HMF in the assay procedure, solanesyl-diphosphate synthase was able to be purified to homogeneity and was found to be a homodimer with a monomeric molecular mass of 34 kDa. In contrast to hexaprenyl- and heptaprenyl-diphosphate synthases, which are composed of two easily dissociable components that are inactive unless combined, the homogeneously purified solanesyl-diphosphate synthase itself showed a catalytic activity, though weak, catalyzing the synthesis of both (all-E)-nonaprenyl-(solanesyl-) and (all-E)-octaprenyl diphosphate. HMF does not affect the stability of solanesyl-diphosphate synthase or Km values for isopentenyl diphosphate and farnesyl diphosphate, but it markedly increases Vmax values in a time-dependent manner. Several lines of evidence indicate that HMF contains a factor which binds to polyprenyl products and removes them out of the active site of enzyme to facilitate and maintain the turnover of catalysis. << Less

  J Biol Chem 266:23706-23713(1991) [PubMed] [EuropePMC]

• Two solanesyl diphosphate synthases with different subcellular localizations and their respective physiological roles in Oryza sativa.

  Ohara K., Sasaki K., Yazaki K.

  Long chain prenyl diphosphates are crucial biosynthetic precursors of ubiquinone (UQ) in many organisms, ranging from bacteria to humans, as well as precursors of plastoquinone in photosynthetic organisms. The cloning and characterization of two solanesyl diphosphate synthase genes, OsSPS1 and OsS ... >> More

  Long chain prenyl diphosphates are crucial biosynthetic precursors of ubiquinone (UQ) in many organisms, ranging from bacteria to humans, as well as precursors of plastoquinone in photosynthetic organisms. The cloning and characterization of two solanesyl diphosphate synthase genes, OsSPS1 and OsSPS2, in Oryza sativa is reported here. OsSPS1 was highly expressed in root tissue whereas OsSPS2 was found to be high in both leaves and roots. Enzymatic characterization using recombinant proteins showed that both OsSPS1 and OsSPS2 could produce solanesyl diphosphates as their final product, while OsSPS1 showed stronger activity than OsSPS2. However, an important biological difference was observed between the two genes: OsSPS1 complemented the yeast coq1 disruptant, which does not form UQ, whereas OsSPS2 only very weakly complemented the growth defect of the coq1 mutant. HPLC analyses showed that both OsSPS1 and OsSPS2 yeast transformants produced UQ9 instead of UQ6, which is the native yeast UQ. According to the complementation study, the UQ9 levels in OsSPS2 transformants were much lower than that of OsSPS1. Green fluorescent protein fusion analyses showed that OsSPS1 localized to mitochondria, while OsSPS2 localized to plastids. This suggests that OsSPS1 is involved in the supply of solanesyl diphosphate for ubiquinone-9 biosynthesis in mitochondria, whereas OsSPS2 is involved in providing solanesyl diphosphate for plastoquinone-9 formation. These findings indicate that O. sativa has a different mechanism for the supply of isoprenoid precursors in UQ biosynthesis from Arabidopsis thaliana, in which SPS1 provides a prenyl moiety for UQ9 at the endoplasmic reticulum. << Less

  J. Exp. Bot. 61:2683-2692(2010) [PubMed] [EuropePMC]