Dimethylsulfoniopropionate Biosynthesis in<i>Spartina alterniflora</i>1

Kocsis, Michael G.; Nolte, Kurt D.; Rhodes, David; Shen, T. L.; Gage, Douglas A.; Hanson, Andrew D.

doi:10.1104/pp.117.1.273

Cited by 81 publications

(48 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…AtHMT-1 has K m values for SMM and AdoMet of 29 and 1950 M, respectively and the V max value with SMM is 2.8-fold higher. SMM levels are reported to range from about 5 to Ͼ300 nmol g Ϫ1 fresh weight in various tissues, and SMM/ AdoMet ratios are reported to range from Ϸ1 to Ͼ30 (1,8,(33)(34)(35)(36). Some SMM may be sequestered in the vacuole; however, radiotracer kinetic studies indicate that the metabolically active (presumably cytosolic) SMM pool is a large fraction of the total (36).…”

Section: Discussionmentioning

confidence: 99%

“…SMM levels are reported to range from about 5 to Ͼ300 nmol g Ϫ1 fresh weight in various tissues, and SMM/ AdoMet ratios are reported to range from Ϸ1 to Ͼ30 (1,8,(33)(34)(35)(36). Some SMM may be sequestered in the vacuole; however, radiotracer kinetic studies indicate that the metabolically active (presumably cytosolic) SMM pool is a large fraction of the total (36). Assuming the cytosol to be Ϸ5% of tissue water volume (37), it follows from these data that typical cytosolic SMM concentrations are likely to be Ն100 M, and AdoMet concentrations are likely to be similar or lower.…”

Section: Discussionmentioning

confidence: 99%

“…Isotope tracer studies of SMM synthesis and metabolism in leaves of these plants showed that the methyl flux from Met to SMM was high, but there was little or none from SMM to Hcy, i.e. the SMM cycle turned slowly if at all (36,42). The approach used to make these measurements depends on the metabolism of SMM to DMSP and so unfortunately cannot be applied to the great majority of plants that do not synthesize DMSP.…”

Section: Figmentioning

confidence: 99%

See 2 more Smart Citations

Characterization and Functional Expression of cDNAs Encoding Methionine-sensitive and -insensitive Homocysteine S-Methyltransferases from Arabidopsis

Ranocha¹,

Bourgis²,

Ziemak³

et al. 2000

Journal of Biological Chemistry

Self Cite

View full text Add to dashboard Cite

Plants synthesize S-methylmethionine (SMM) from Sadenosylmethionine (AdoMet), and methionine (Met) by a unique reaction and, like other organisms, use SMM as a methyl donor for Met synthesis from homocysteine (Hcy). These reactions comprise the SMM cycle. Two Arabidopsis cDNAs specifying enzymes that mediate the SMM 3 Met reaction (SMM:Hcy S-methyltransferase, HMT) were identified by homology and authenticated by complementing an Escherichia coli yagD mutant and by detecting HMT activity in complemented cells. Gel blot analyses indicate that these enzymes, AtHMT-1 and -2, are encoded by single copy genes. The deduced polypeptides are similar in size (36 kDa), share a zincbinding motif, lack obvious targeting sequences, and are 55% identical to each other. The recombinant enzymes exist as monomers. AtHMT-1 and -2 both utilize L-SMM or (S,S)-AdoMet as a methyl donor in vitro and have higher affinities for SMM. Both enzymes also use either methyl donor in vivo because both restore the ability to utilize AdoMet or SMM to a yeast HMT mutant. However, AtHMT-1 is strongly inhibited by Met, whereas AtHMT-2 is not, a difference that could be crucial to the control of flux through the HMT reaction and the SMM cycle. Plant HMT is known to transfer the pro-R methyl group of SMM. This enabled us to use recombinant AtHMT-1 to establish that the other enzyme of the SMM cycle, AdoMet:Met S-methyltransferase, introduces the pro-S methyl group. These opposing stereoselectivities suggest a way to measure in vivo flux through the SMM cycle.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Figmentioning

confidence: 99%

See 1 more Smart Citation

Characterization and Functional Expression of cDNAs Encoding Methionine-sensitive and -insensitive Homocysteine S-Methyltransferases from Arabidopsis

Ranocha¹,

Bourgis²,

Ziemak³

et al. 2000

Journal of Biological Chemistry

Self Cite

View full text Add to dashboard Cite

show abstract

“…The computer model used was similar to the metabolic flux analysis model described by Kocsis et al (1998). Programs were written in Microsoft Visual Basic.…”

Section: Measurement Of Ptd-base Pool Sizesmentioning

confidence: 99%

Radiotracer and Computer Modeling Evidence that Phospho-Base Methylation Is the Main Route of Choline Synthesis in Tobacco

et al. 2000

Self Cite

View full text Add to dashboard Cite

Among flowering plants, the synthesis of choline (Cho) from ethanolamine (EA) can potentially occur via three parallel, interconnected pathways involving methylation of free bases, phospho-bases, or phosphatidyl-bases. We investigated which pathways operate in tobacco (Nicotiana tabacum L.) because previous work has shown that the endogenous Cho supply limits accumulation of glycine betaine in transgenic tobacco plants engineered to convert Cho to glycine betaine. 14 C]formate metabolism required consideration of the labeling of the EA and methyl moieties of Cho. Results supported the following conclusions: (a) The first methylation step occurs solely at the phospho-base level; (b) the second and third methylations occur mainly (83%-92% and 65%-85%, respectively) at the phospho-base level, with the remainder occurring at the phosphatidyl-base level; and (c) free Cho originates predominantly from phosphatidylcholine rather than from phospho-Cho. This study illustrates how computer modeling of radiotracer data, in conjunction with information on chemical pool sizes, can provide a coherent, quantitative picture of fluxes within a complex metabolic network.All plants synthesize modest amounts of choline (Cho) for incorporation into the membrane phospholipid phosphatidylcholine (Ptd-Cho); the Cho requirement for Ptd-Cho synthesis is approximately 1 to 2 mol g Ϫ1 fresh weight (Rhodes and Hanson, 1993). In certain plants, Cho has an additional fateoxidation to the osmoprotectant glycine betaine (GlyBet) (Gorham, 1995). Such plants may accumulate GlyBet to levels exceeding 20 mol g Ϫ1 fresh weight, and so must produce far more Cho than those that lack GlyBet (Rhodes and Hanson, 1993). This difference between GlyBet accumulators and nonaccumulators is highlighted by the results of expressing bacterial or plant genes for GlyBet synthesis in non-accumulators such as tobacco (Nicotiana tabacum L.) and Arabidopsis. The engineered plants produce relatively little GlyBet (Ͻ0.2-2 mol g Ϫ1 fresh weight) unless they are given exogenous Cho, whereupon GlyBet levels increase by Ͼ20-fold (Hayashi et al., 1997;Nuccio et al., 1998; Huang et al., 2000, and refs. therein). The evidence that the endogenous Cho supply in tobacco cannot support high levels of GlyBet synthesis focused our attention on how Cho is made in this species, and on how metabolic flux to Cho is regulated. Cho biogenesis has not been investigated in tobacco or other Solanaceae, but radiotracer and enzymatic evidence for diverse plants (both GlyBet accumulators and nonaccumulators) indicates that it can proceed via three parallel, interconnected paths involving sequential methylations of an ethanolamine (EA) moiety at the free base, phospho-base (P-base), or phosphatidyl-base (Ptd-base) levels (for review, see Rhodes and Hanson, 1993). Figure 1 shows the full network of these reactions. The situation may be simpler in leaves, where there is evidence only for P-base and Ptd-base pathways, the free base route having been found only in endosperm Moore, 1992a, 1992b). ...

show abstract

“…This sulfonium compound is accumulated by many marine algae and by the angiosperms Wollastonia biflora and Spartina alterniflora (see Ref. 7 and references therein). Dimethylsulfoniopropionate has been shown to function as an osmoprotectant for bacteria (8,9), and the accumulation of dimethylsulfoniopropionate to high levels in the cytoplasm of algal cells and in W. biflora chloroplasts supports the idea that it functions also in plants as an osmoprotectant (10)(11)(12).…”

mentioning

confidence: 99%

Transport of Sulfonium Compounds

Rouillon¹,

Surdin-Kerjan

Thomas

1999

Journal of Biological Chemistry

View full text Add to dashboard Cite

We report here the characterization and the molecular analysis of the two high affinity permeases that mediate the transport of S-adenosylmethionine (AdoMet) and S-methylmethionine (SMM) across the plasma membrane of yeast cells. Mutant cells unable to use AdoMet as a sulfur source were first isolated and demonstrated to lack high affinity AdoMet transport capacities. Functional complementation cloning allowed us to identify the corresponding gene (SAM3), which encodes an integral membrane protein comprising 12 putative membrane spanning regions and belonging to the amino acid permease family. Among amino acid permease members, the closest relative of Sam3p is encoded by the YLL061w open reading frame. Disruption of YLL061w was shown to specifically lead to cells unable to use SMM as a sulfur source. Accordingly, transport assays demonstrated that YLL061w disruption mutation impaired the high affinity SMM permease, and YLL061w was therefore renamed MMP1. Further study of sam3⌬ and mmp1⌬ mutant cells showed that in addition to high affinity permeases, both sulfonium compounds are transported into yeast cells by low affinity transport systems that appear to be carrier-facilitated diffusion.

show abstract

Dimethylsulfoniopropionate Biosynthesis inSpartina alterniflora1

Abstract: The osmoprotectant 3-dimethylsulfoniopropionate (DMSP) occurs in Gramineae and Compositae, but its synthesis has been studied only in the latter. The DMSP synthesis pathway was therefore investigated in the salt marsh grass Spartina alterniflora Loisel.

Cited by 81 publications

References 34 publications

Characterization and Functional Expression of cDNAs Encoding Methionine-sensitive and -insensitive Homocysteine S-Methyltransferases from Arabidopsis

Characterization and Functional Expression of cDNAs Encoding Methionine-sensitive and -insensitive Homocysteine S-Methyltransferases from Arabidopsis

Radiotracer and Computer Modeling Evidence that Phospho-Base Methylation Is the Main Route of Choline Synthesis in Tobacco

Transport of Sulfonium Compounds

Contact Info

Product

Resources

About