Publications

• Removal of phosphoglycolate in hyperthermophilic archaea.

  Michimori Y., Izaki R., Su Y., Fukuyama Y., Shimamura S., Nishimura K., Miwa Y., Hamakita S., Shimosaka T., Makino Y., Takeno R., Sato T., Beppu H., Cann I., Kanai T., Nunoura T., Atomi H.

  Many organisms that utilize the Calvin-Benson-Bassham (CBB) cycle for autotrophic growth harbor metabolic pathways to remove and/or salvage 2-phosphoglycolate, the product of the oxygenase activity of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco). It has been presumed that the occurren ... >> More

  Many organisms that utilize the Calvin-Benson-Bassham (CBB) cycle for autotrophic growth harbor metabolic pathways to remove and/or salvage 2-phosphoglycolate, the product of the oxygenase activity of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco). It has been presumed that the occurrence of 2-phosphoglycolate salvage is linked to the CBB cycle, and in particular, the C2 pathway to the CBB cycle and oxygenic photosynthesis. Here, we examined 2-phosphoglycolate salvage in the hyperthermophilic archaeon <i>Thermococcus kodakarensis</i>, an obligate anaerobe that harbors a Rubisco that functions in the pentose bisphosphate pathway. <i>T. kodakarensis</i> harbors enzymes that have the potential to convert 2-phosphoglycolate to glycine and serine, and their genes were identified by biochemical and/or genetic analyses. 2-phosphoglycolate phosphatase activity increased 1.6-fold when cells were grown under microaerobic conditions compared to anaerobic conditions. Among two candidates, TK1734 encoded a phosphatase specific for 2-phosphoglycolate, and the enzyme was responsible for 80% of the 2-phosphoglycolate phosphatase activity in <i>T. kodakarensis</i> cells. The TK1734 disruption strain displayed growth impairment under microaerobic conditions, which was relieved upon addition of sodium sulfide. In addition, glycolate was detected in the medium when <i>T. kodakarensis</i> was grown under microaerobic conditions. The results suggest that <i>T. kodakarensis</i> removes 2-phosphoglycolate via a phosphatase reaction followed by secretion of glycolate to the medium. As the Rubisco in <i>T. kodakarensis</i> functions in the pentose bisphosphate pathway and not in the CBB cycle, mechanisms to remove 2-phosphoglycolate in this archaeon emerged independent of the CBB cycle. << Less

  Proc Natl Acad Sci U S A 121:e2311390121-e2311390121(2024) [PubMed] [EuropePMC]

  This publication is cited by 21 other entries.

• Oxidation and reduction of glycolic and glyoxylic acids in plants. II. Glyoxylic acid reductase.

  ZELITCH I.

  J Biol Chem 201:719-726(1953) [PubMed] [EuropePMC]

• The isolation and action of crystalline glyoxylic acid reductase from tobacco leaves.

  ZELITCH I.

  J Biol Chem 216:553-575(1955) [PubMed] [EuropePMC]

• An aldo-keto reductase with 2-keto-l-gulonate reductase activity functions in l-tartaric acid biosynthesis from vitamin C in Vitis vinifera.

  Jia Y., Burbidge C.A., Sweetman C., Schutz E., Soole K., Jenkins C., Hancock R.D., Bruning J.B., Ford C.M.

  Tartaric acid has high economic value as an antioxidant and flavorant in food and wine industries. l-Tartaric acid biosynthesis in wine grape (<i>Vitis vinifera</i>) uses ascorbic acid (vitamin C) as precursor, representing an unusual metabolic fate for ascorbic acid degradation. Reduction of the ... >> More

  Tartaric acid has high economic value as an antioxidant and flavorant in food and wine industries. l-Tartaric acid biosynthesis in wine grape (<i>Vitis vinifera</i>) uses ascorbic acid (vitamin C) as precursor, representing an unusual metabolic fate for ascorbic acid degradation. Reduction of the ascorbate breakdown product 2-keto-l-gulonic acid to l-idonic acid constitutes a critical step in this l-tartaric acid biosynthetic pathway. However, the underlying enzymatic mechanisms remain obscure. Here, we identified a <i>V. vinifera</i> aldo-keto reductase, Vv2KGR, with 2-keto-l-gulonic acid reductase activity. Vv2KGR belongs to the d-isomer-specific 2-hydroxyacid dehydrogenase superfamily and displayed the highest similarity to the hydroxyl pyruvate reductase isoform 2 in <i>Arabidopsis thaliana</i> Enzymatic analyses revealed that Vv2KGR efficiently reduces 2-keto-l-gulonic acid to l-idonic acid and uses NADPH as preferred coenzyme. Moreover, Vv2KGR exhibited broad substrate specificity toward glyoxylate, pyruvate, and hydroxypyruvate, having the highest catalytic efficiency for glyoxylate. We further determined the X-ray crystal structure of Vv2KGR at 1.58 Å resolution. Comparison of the Vv2KGR structure with those of d-isomer-specific 2-hydroxyacid dehydrogenases from animals and microorganisms revealed several unique structural features of this plant hydroxyl pyruvate reductase. Substrate structural analysis indicated that Vv2KGR uses two modes (A and B) to bind different substrates. 2-Keto-l-gulonic acid displayed the lowest predicted free-energy binding to Vv2KGR among all docked substrates. Hence, we propose that Vv2KGR functions in l-tartaric acid biosynthesis. To the best of our knowledge, this is the first report of a d-isomer-specific 2-hydroxyacid dehydrogenase that reduces 2-keto-l-gulonic acid to l-idonic acid in plants. << Less

  J. Biol. Chem. 294:15932-15946(2019) [PubMed] [EuropePMC]

  This publication is cited by 6 other entries.