The role of 2‐methyl‐6‐phytylbenzoquinone methyltransferase in determining tocopherol composition in <i>Synechocystis</i> sp. PCC6803

Shintani, David K.; Cheng, Zigang; DellaPenna, Dean

doi:10.1016/s0014-5793(01)03223-9

Cited by 75 publications

(68 citation statements)

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“…Previous studies have demonstrated that tocopherol biosynthetic enzymes are remarkably conserved in both primary sequence and activity in cyanobacteria and plants (Norris et al, 1998;Shintani and DellaPenna, 1998;Collakova and DellaPenna, 2001;Porfirova et al, 2002;Shintani et al, 2002;Sattler et al, 2003). In this regard, the low sequence identity of MPBQ/ MSBQ MT in Arabidopsis and Synechocystis sp PCC6803 stands in stark contrast to other pathway enzymes and suggests that although similar, fundamental differences exist in tocopherol and PQ synthesis in cyanobacteria and plants.…”

Section: New Insights Into the Synthesis And Regulation Of Tocopherolmentioning

confidence: 99%

“…Growth, induction, cell harvesting, and extraction of engineered proteins in E. coli were performed as described by Shintani et al (2002). Cells carrying an empty pET30A vector also were induced as a negative control.…”

Section: Escherichia Colimentioning

confidence: 99%

“…Most tocopherol pathway enzymes have been isolated only recently by combining genetic and genomic approaches in Synechocystis sp PCC6803 and Arabidopsis, in which the isolation of an enzyme from one organism has facilitated the isolation of the respective ortholog from the other. Sequencing of the Synechocystis sp PCC6803 and Arabidopsis genomes has greatly facilitated this process, so that now, HPPD, HPT, TC, and ␥ -TMT have been cloned and characterized from both organisms (Norris et al, 1998;Shintani and DellaPenna, 1998;Collakova and DellaPenna, 2001;Shintani et al, 2002;Porfirova et al, 2002;Sattler et al, 2003). Although these studies have shown that these four pathway steps and enzymes are conserved between cyanobacteria and plants, other studies have provided evidence that portions of the tocopherol and PQ pathways are not identical in the two organisms.…”

Section: Introductionmentioning

confidence: 99%

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Highly Divergent Methyltransferases Catalyze a Conserved Reaction in Tocopherol and Plastoquinone Synthesis in Cyanobacteria and Photosynthetic Eukaryotes

Cheng

Sattler

Maéda

et al. 2003

THE PLANT CELL ONLINE

197

176

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Tocopherols are lipid-soluble compounds synthesized only by photosynthetic eukaryotes and oxygenic cyanobacteria. The pathway and enzymes for tocopherol synthesis are homologous in cyanobacteria and plants except for 2-methyl-6-phytyl-1,4-benzoquinone/2-methyl-6-solanyl-1,4-benzoquinone methyltransferase (MPBQ/MSBQ MT), which catalyzes a key methylation step in both tocopherol and plastoquinone (PQ) synthesis. Using a combined genomic, genetic, and biochemical approach, we isolated and characterized the VTE3 (vitamin E defective) locus, which encodes MPBQ/MSBQ MT in Arabidopsis. The phenotypes of vte3 mutants are consistent with the disruption of MPBQ/MSBQ MT activity to varying extents. The ethyl methanesulfonate-derived vte3-1 allele alters tocopherol composition but has little impact on PQ levels, whereas the null vte3-2 allele is deficient in PQ and ␣ -and ␥ -tocopherols. In vitro enzyme assays confirmed that VTE3 is the plant functional equivalent of the previously characterized MPBQ/MSBQ MT (Sll0418) from Synechocystis sp PCC6803, although the two proteins are highly divergent in primary sequence. Sll0418 orthologs are present in all fully sequenced cyanobacterial genomes, Chlamydomonas reinhardtii , and the diatom Thalassiosira pseudonana but absent from vascular and nonvascular plant databases. VTE3 orthologs are present in all vascular and nonvascular plant databases and in C. reinhardtii but absent from cyanobacterial genomes. Intriguingly, the only prokaryotic genomes that contain VTE3-like sequences are those of two species of archea, suggesting that, in contrast to all other enzymes of the plant tocopherol pathway, the evolutionary origin of VTE3 may have been archeal rather than cyanobacterial. In vivo analyses of vte3 mutants and the corresponding homozygous Synechocystis sp PCC6803 sll0418 :: aphII mutant revealed important differences in enzyme redundancy, the regulation of tocopherol synthesis, and the integration of tocopherol and PQ biosynthesis in cyanobacteria and plants.

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Section: New Insights Into the Synthesis And Regulation Of Tocopherolmentioning

confidence: 99%

Section: Escherichia Colimentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Highly Divergent Methyltransferases Catalyze a Conserved Reaction in Tocopherol and Plastoquinone Synthesis in Cyanobacteria and Photosynthetic Eukaryotes

Cheng

Sattler

Maéda

et al. 2003

THE PLANT CELL ONLINE

197

176

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“…Insertional inactivation of the genes encoding each enzyme of the pathway has resulted in a series of mutants in which the content and composition of tocopherol species vary. For example, the slr0089 mutant accumulates only g-tocopherol (Shintani and DellaPenna, 1998), the sll0418 mutant accumulates 30% of the wild-type level of a-tocopherol and a small amount of b-tocopherol (Shintani et al, 2002;Cheng et al, 2003), whereas the slr1736 mutant lacks all tocopherols (Collakova and DellaPenna, 2001). In light of the established antioxidant activity of a-tocopherol, one would expect that a loss or reduction of a-tocopherol would lead to an obvious phenotypic difference between the wild-type and mutant strains.…”

mentioning

confidence: 99%

α-Tocopherol Plays a Role in Photosynthesis and Macronutrient Homeostasis of the Cyanobacterium Synechocystis sp. PCC 6803 That Is Independent of Its Antioxidant Function

et al. 2006

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a-Tocopherol is synthesized exclusively in oxygenic phototrophs and is known to function as a lipid-soluble antioxidant. Here, we report that a-tocopherol also has a novel function independent of its antioxidant properties in the cyanobacterium Synechocystis sp. PCC 6803. The photoautotrophic growth rates of wild type and mutants impaired in a-tocopherol biosynthesis are identical, but the mutants exhibit elevated photosynthetic activities and glycogen levels. When grown photomixotrophically with glucose (Glc), however, these mutants cease growth within 24 h and exhibit a global macronutrient starvation response associated with nitrogen, sulfur, and carbon, as shown by decreased phycobiliprotein content (35% of the wild-type level) and accumulation of the nblA1-nblA2, sbpA, sigB, sigE, and sigH transcripts. Photosystem II activity and carboxysome synthesis are lost in the tocopherol mutants within 24 h of photomixotrophic growth, and the abundance of carboxysome gene (rbcL, ccmK1, ccmL) and ndhF4 transcripts decreases to undetectable levels. These results suggest that a-tocopherol plays an important role in optimizing photosynthetic activity and macronutrient homeostasis in Synechocystis sp. PCC 6803. Several lines of evidence indicate that increased oxidative stress in the tocopherol mutants is unlikely to be the underlying cause of photosystem II inactivation and Glcinduced lethality. Interestingly, insertional inactivation of the pmgA gene, which encodes a putative serine-threonine kinase similar to RsbW and RsbT in Bacillus subtilis, results in a similar increase in glycogen and Glc-induced lethality. Based on these results, we propose that a-tocopherol plays a nonantioxidant regulatory role in photosynthesis and macronutrient homeostasis through a signal transduction pathway that also involves PmgA.

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“…As one of the critical enzymes involved in plant vitamin E biosynthesis, 2-methyl-6-phytyl-1,4-benzoquinol methyltransferase (MPBQ MT) can catalyze MPBQ to generate 2,3-dimethyl-6-phytyl-1,4-benzoquinone (DMPBQ). MPBQ and DMPBQ, however, are cyclized by tocopherol cyclase to yield δ-and γ-tocopherol, respectively, which are subsequently further converted to β-and α-tocopherol by γ-tocopherol methyltransferase (γ-TMT) (Shintani and DellaPenna, 1998;Porfirova et al, 2002;Shintani et al, 2002).…”

Section: Introductionmentioning

confidence: 99%

Cloning and polymorphism analysis of the 2-methyl-6-phytyl-1,4-benzoquinol methyltransferase gene (VTE3) in Arachis hypogaea, A. duranensis, and A. ipaënsis

Liu

Guo²,

Wan³

2013

Genet. Mol. Res.

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ABSTRACT. One of the critical enzymes involved in vitamin E biosynthesis in plants is 2-methyl-6-phytyl-1,4-benzoquinol methyltransferase (MPBQ MT). The full-length VTE3 cDNA (designated rVTE3-1 and -2) encoding MPBQ MT and the full-length DNA of VTE3 (designated gVTE3-1 and -2) were isolated from cultivated peanuts (Arachis hypogaea). The full-length DNA of VTE3 (designated gVTE3-A and -B) was isolated from the wild groundnut species A. duranensis (A-genome) and A. ipaënsis (B-genome), and polymorphism analysis of VTE3 was performed. The results demonstrated that rVTE3-1 and -2 both have a DNA sequence that is 1059 bp long and encodes 351 amino acids; the homology of the 2 amino acid sequences was 98.6%. The gVTE3-1 of cultivated Fenghua 2 peanut samples was 2710 bp long, with 3 introns located at 44-163, 772-1295, and 1603-2437 bp, and the Fenghua 2 gVTE3-2 was 2706 bp long, with 3 introns located at (2013) 44-169, 778-1291, and 1599-2433 bp. The homology for gVTE3-1 and -2 across 13 cultivated peanut samples was 99.9 and 100%, respectively. gVTE3-1 and -2 were from A-and B-genome, respectively, with 96.6% homology between the 2 sequences. The present study demonstrated that abundant polymorphisms were present in the VTE3 genes from different genomes. Additionally, polymorphisms were observed in the gVTE3-1 alleles of the 13 cultivars and wild A. duranensis species but not in the gVTE3-2 alleles of the 13 cultivars and wild A. ipaënsis species.

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The role of 2‐methyl‐6‐phytylbenzoquinone methyltransferase in determining tocopherol composition in Synechocystis sp. PCC6803

Cited by 75 publications

References 14 publications

Highly Divergent Methyltransferases Catalyze a Conserved Reaction in Tocopherol and Plastoquinone Synthesis in Cyanobacteria and Photosynthetic Eukaryotes

Highly Divergent Methyltransferases Catalyze a Conserved Reaction in Tocopherol and Plastoquinone Synthesis in Cyanobacteria and Photosynthetic Eukaryotes

α-Tocopherol Plays a Role in Photosynthesis and Macronutrient Homeostasis of the Cyanobacterium Synechocystis sp. PCC 6803 That Is Independent of Its Antioxidant Function

Cloning and polymorphism analysis of the 2-methyl-6-phytyl-1,4-benzoquinol methyltransferase gene (VTE3) in Arachis hypogaea, A. duranensis, and A. ipaënsis

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