The Glycine Decarboxylase Complex from Plant Mitochondria

Oliver, David J.

doi:10.1146/annurev.pp.45.060194.001543

Cited by 135 publications

(57 citation statements)

References 40 publications

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“…Aspartic acid can be converted into oxalo-acetate (Mazelis 1980) while glycine can be transformed into pyruvate via serine respiring the carboxylic-C in the process (Oliver 1994). To avoid losing the 13 C via respiration after it entered the plant we used 15 N, 13 C-2 glycine, which is labelled on the non-carboxylic C atom.…”

Section: Methodological Issuesmentioning

confidence: 99%

Amino acid uptake among wide-ranging moss species may contribute to their strong position in higher-latitude ecosystems

Krab¹,

Cornelissen²,

Lang³

et al. 2008

Plant Soil

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Plants that can take up amino acids directly from the soil solution may have a competitive advantage in ecosystems where inorganic nitrogen sources are scarce. We hypothesized that diverse mosses in cold, N-stressed ecosystems share this ability. We experimentally tested 11 sub-arctic Swedish moss species of wide-ranging taxa and growth form for their ability to take up double labelled ( 15 N and 13 C) glycine and aspartic acid in a laboratory setup as well as in a realistic field setting. All species were able to take up amino acids injected into the soil solution to some extent, although field uptake was marginal to absent for the endohydric Polytrichum commune. The 11 moss species on average took up 36±5% of the injected glycine and 18±2% of the aspartic acid in the lab experiment. Field uptake of both glycine (24± 5%) and aspartic acid (10±2%) was lower than in the lab. Overall differences in uptake amongst species appeared to be positively associated with habitat wetness and/or turf density among different Sphagnum species and among non-Sphagnum species, respectively. Species from habitats of lower inorganic N availability, as indicated tentatively by lower tissue N concentrations, showed relatively strong amino acid uptake, but this was only significant for the field uptake among non-Sphagnum mosses. Further experiments are needed to test for consistent differences in amino acid uptake capacity among species and functional groups as determined by their functional traits, and to test how the affinity of cold-biome mosses for amino acids compares to that for ammonium or nitrate. Still, our results support the view that widespread moss species in cold, N-stressed ecosystems may derive a significant proportion of their nitrogen demand from free amino acids. This might give them a competitive advantage over plants that depend strongly on inorganic N sources.

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Section: Methodological Issuesmentioning

confidence: 99%

Amino acid uptake among wide-ranging moss species may contribute to their strong position in higher-latitude ecosystems

Krab¹,

Cornelissen²,

Lang³

et al. 2008

Plant Soil

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“…To confirm the localization of lipoic acid synthase in mitochondria, the same fractionated samples were analyzed by western analysis with an antibody against pea H-protein, which is a subunit of the Gly-decarboxylase complex and is present in the matrix of mitochondria (Oliver, 1994). As shown in Figure 7, bottom, the H-protein was detected in the mitochondrial and chloroplast fractions, although the intensity of the H-protein band in the mitochondrial fraction was much stronger than that of the band in the chloroplast fraction.…”

Section: Intracellular Localization Of Lipoic Acid Synthase In Arabidmentioning

confidence: 99%

Biosynthesis of Lipoic Acid in Arabidopsis: Cloning and Characterization of the cDNA for Lipoic Acid Synthase

Yasuno

Wada

1998

Plant Physiology

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Lipoic acid is a coenzyme that is essential for the activity of enzyme complexes such as those of pyruvate dehydrogenase and glycine decarboxylase. We report here the isolation and characterization of LIP1 cDNA for lipoic acid synthase of Arabidopsis. The Arabidopsis LIP1 cDNA was isolated using an expressed sequence tag homologous to the lipoic acid synthase of Escherichia coli. This cDNA was shown to code for Arabidopsis lipoic acid synthase by its ability to complement a lipA mutant of E. coli defective in lipoic acid synthase. DNA-sequence analysis of the LIP1 cDNA revealed an open reading frame predicting a protein of 374 amino acids. Comparisons of the deduced amino acid sequence with those of E. coli and yeast lipoic acid synthase homologs showed a high degree of sequence similarity and the presence of a leader sequence presumably required for import into the mitochondria. Southernhybridization analysis suggested that LIP1 is a single-copy gene in Arabidopsis. Western analysis with an antibody against lipoic acid synthase demonstrated that this enzyme is located in the mitochondrial compartment in Arabidopsis cells as a 43-kD polypeptide.Lipoic acid (6,8-thioctic acid) is a sulfur-containing coenzyme that is required for the activity of enzyme complexes involved in the oxidative decarboxylation of ␣-ketoacids (Reed and Hackert, 1990;Perham, 1991;Mattevi et al., 1992) and in the Gly-cleavage system (Fujiwara et al., 1990;Kim and Oliver, 1990;Macherel et al., 1990). There are five lipoyl proteins: the dihydrolipoamide acyltransferase subunits of pyruvate, ␣-ketoglutarate, branched-chain ␣-ketoacid dehydrogenase complexes, protein X of the pyruvate dehydrogenase complex, and the H-protein of the Gly-cleavage system. Lipoic acid is covalently bound to these proteins via an amide linkage to the ⑀-amino group of specific Lys residues (Reed and Hackert, 1966). The lipoylLys arm functions as a carrier of reaction intermediates, and reducing equivalents interact with the active sites of the components of the complexes (Yeaman, 1989; Douce et al., 1994).Despite the importance of the lipoyl-prosthetic group in the functioning of several enzyme complexes, the biosynthesis of lipoic acid is not well understood in any organism. Molecular genetic studies (Vanden Boom et al., 1991;Reed and Cronan, 1993;Morris et al., 1994Morris et al., , 1995 of Escherichia coli have identified three genes, lipA, lipB, and lplA that are involved in the biosynthesis and transfer of lipoic acid. lipA encodes a lipoic acid synthase that is required for an insertion of the first sulfur atom into the octanoate backbone (Reed and Cronan, 1993). lplA and lipB encode lipoate ligases that are involved in the transfer of lipoic acid to cognate proteins (Morris et al., 1994(Morris et al., , 1995. LplA and LipB proteins primarily function in the utilization of lipoic acid exogenously added to the growth medium and endogenously synthesized lipoic acid in E. coli cells, respectively (Morris et al., 1994(Morris et al., , 1995. LplA protein is involved...

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“…NADH competitively inhibits GDC, and the increase in ionic strength and pH leads to dissociation of the complex [17]. The conditions of rapid binding or outflow of the reaction products change the relative contributions of steps 1 and 2.…”

Section: Discussionmentioning

confidence: 99%

Fractionation of carbon (¹³C/¹²C) isotopes in glycine decarboxylase reaction

1996

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Fractionation of carbon isotopes (13C/12C) by glycine decarboxylase (GDC) was investigated in mitochondrial preparations isolated from photosynthetic tissues of different plants (Pisum, Medicago, Triticum, Hordeum, Spinacia, Brassica, Wolffia). 20 mM glycine was supplied to mitochondria, and the CO2 formed was absorbed and analyzed for isotopic content.CO2 evolved by mitochondria of Pisum was enriched up to 8 %o in 12C compared to the carboxylic atom of glycine. CO2 evolved by mitochondria of the other plants investigated was enriched by 5-16 %o in 13C. Carbon isotope effects were sensitive to reaction conditions (pH and the presence of GDC cofactors). Theoretical treatment of the reaction mechanism enabled us to conclude that the value and even the sign of the carbon isotope effect in glycine decarboxylation depend on the contribution of the enzymesubstrate binding step and of the decarboxylation step itself to the overall reaction rate. Therefore, the fractionation of carbon isotopes in GDC reaction was revealed which provides essential isotopic effects in plants in addition to the well-known effect of carbon isotope fractionation by the central photosynthetic enzyme, ribulose-l,5-biphosphate carboxylase.

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The Glycine Decarboxylase Complex from Plant Mitochondria

Cited by 135 publications

References 40 publications

Amino acid uptake among wide-ranging moss species may contribute to their strong position in higher-latitude ecosystems

Amino acid uptake among wide-ranging moss species may contribute to their strong position in higher-latitude ecosystems

Biosynthesis of Lipoic Acid in Arabidopsis: Cloning and Characterization of the cDNA for Lipoic Acid Synthase

Fractionation of carbon (¹³C/¹²C) isotopes in glycine decarboxylase reaction

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The Glycine Decarboxylase Complex from Plant Mitochondria

Cited by 135 publications

References 40 publications

Amino acid uptake among wide-ranging moss species may contribute to their strong position in higher-latitude ecosystems

Amino acid uptake among wide-ranging moss species may contribute to their strong position in higher-latitude ecosystems

Biosynthesis of Lipoic Acid in Arabidopsis: Cloning and Characterization of the cDNA for Lipoic Acid Synthase

Fractionation of carbon (13C/12C) isotopes in glycine decarboxylase reaction

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Fractionation of carbon (¹³C/¹²C) isotopes in glycine decarboxylase reaction