Fatty acyl-coA and fatty acyl-acyl carrier protein as acyl donors in the synthesis of lysophosphatidate and phosphatidate in escherichia coli

Bosch, H. Van Den; Vagelos, P. Roy

doi:10.1016/0005-2760(70)90142-6

Cited by 135 publications

(53 citation statements)

References 45 publications

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“…Although some acid phosphatases are active at pHs as high as 8.0, their optimal activity ranges are reported to be around pH 5.0 and are generally characterized as being magnesium independent (9,29). The pH optimum for the periplasmic alkaline phosand lysoPA-tase activities described by Van den Bosch and Vagelos (37), which show no inhibition by fluoride and no dependence on magnesium.…”

Section: Resultsmentioning

confidence: 99%

The pgpA and pgpB genes of Escherichia coli are not essential: evidence for a third phosphatidylglycerophosphate phosphatase

Funk¹,

Zimniak²,

Dowhan³

1992

J Bacteriol

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To further define the genes and gene products responsible for the in vivo conversion of phosphatidylglycerophosphate to phosphatidylglycerol in Escherichia coli, we disrupted two genes (pgpA and pgpB) which had previously been shown to encode gene products which carried out this reaction in vitro (T. Icho and C. R. H. Raetz, J. Bacteriol. 153:722-730, 1983). Strains with either gene or both genes disrupted had the same properties as the original mutants isolated with mutations in these genes, i.e., reduced in vitro phospholipid phosphatase activities, normal growth properties, and an increase in the level of phosphatidylglycerophosphate (1.6% versus <0.1% in wild-type strains). These results demonstrate that these genes are not required for either normal cell growth or the biosynthesis of phosphatidylglycerol in vivo. In addition, the total phosphatidylglycerophosphate phosphatase activity in the doubly disrupted mutant was reduced by only 50%, which indicates that there is at least one other gene that encodes such an activity and thus accounts for the lack of a dramatic effect on the biosynthesis of anionic phospholipids in these mutant strains. The phosphatidic acid and lysophosphatidic acid phosphatase activities of the pgpB gene product were also significantly reduced in gene-interrupted mutants, but the detection of residual phosphatase activities in these mutants indicated that additional genes encoding such phosphatases exist. The lack of a significant phenotype resulting from disruption of the pgpA and pgpB genes indicates that these genes may be required only for nonessential cell function and leaves the biosynthesis of phosphatidylglycerophosphate as the only step in E. coli phospholipid biosynthesis for which a gene locus has not been identified.Phosphatidylglycerol (PG) is a multifunctional phospholipid in Escherichia coli (30). As the major anionic membrane phospholipid, PG makes up roughly 20% of the total phospholipid in actively growing cells and is turned over to a significant extent in vivo. PG serves as a precursor for a variety of cellular metabolites, including cardiolipin (14), several outer membrane lipoproteins (see reference 11 for a list of references) including the major murein lipoprotein (5), and membrane-derived oligosaccharides (36). It is also a critical component in the SecA-dependent translocation of proteins across the cytoplasmic membrane (21,22). PG is synthesized from CDP-diacylglycerol in two steps. Phosphatidylglycerophosphate (PGP) is first synthesized by transfer of the phosphatidyl backbone from CDP-diacylglycerol to sn-glycerol-3-phosphate (19). PGP is then rapidly dephosphorylated by PGP phosphatase (PGP-tase) to produce PG. Under normal circumstances PGP does not accumulate, which suggests that the regulation of acidic phospholipid biosynthesis occurs before the phosphatase step (18). Our laboratory has previously shown that the gene (pgsA) encoding PGP synthase is essential, thus establishing that acidic phospholipids are necessary for cell growth (12). As a consequ...

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Section: Resultsmentioning

confidence: 99%

The pgpA and pgpB genes of Escherichia coli are not essential: evidence for a third phosphatidylglycerophosphate phosphatase

Funk¹,

Zimniak²,

Dowhan³

1992

J Bacteriol

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“…In an attempt to define the biochemical function(s) of OlsA and PlsC316, combined GPAT-AGPAT activities were assayed in vitro by using radiolabeled G3P as the acyl acceptor and acyl-ACP as the acyl donor, as described in Materials and Methods. Unlike the E. coli GPAT and AGPAT enzymes, which can use either acyl-CoA or acyl-ACP as acyl donors (47), Rhodobacter sphaeroides enzymes exhibit high specificity for acyl-ACP compared to acyl-CoA (34). No significant enzyme activity was observed with the acyl-CoA substrate in R. capsulatus (data not shown) as in R. sphaeroides.…”

Section: Plsc316mentioning

confidence: 99%

Rhodobacter capsulatus OlsA Is a Bifunctional Enyzme Active in both Ornithine Lipid and Phosphatidic Acid Biosynthesis

et al. 2007

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The Rhodobacter capsulatus genome contains three genes (olsA [plsC138], plsC316, and plsC3498) that are annotated as lysophosphatidic acid (1-acyl-sn-glycerol-3-phosphate) acyltransferase (AGPAT). Of these genes, olsA was previously shown to be an O-acyltransferase in the second step of ornithine lipid biosynthesis, which is important for optimal steady-state levels of c-type cytochromes (S. Aygun-Sunar, S. Mandaci, H.-G. Koch, I. V. J. Murray, H. Goldfine, and F. Daldal. Mol. Microbiol. 61:418-435, 2006). The roles of the remaining plsC316 and plsC3498 genes remained unknown. In this work, these genes were cloned, and chromosomal insertion-deletion mutations inactivating them were obtained to define their function. Characterization of these mutants indicated that, unlike the Escherichia coli plsC, neither plsC316 nor plsC3498 was essential in R. capsulatus. In contrast, no plsC316 olsA double mutant could be isolated, indicating that an intact copy of either olsA or plsC316 was required for R. capsulatus growth under the conditions tested. Compared to OlsA null mutants, PlsC316 null mutants contained ornithine lipid and had no c-type cytochrome-related phenotype. However, they exhibited slight growth impairment and highly altered total fatty acid and phospholipid profiles. Heterologous expression in an E. coli plsC(Ts) mutant of either R. capsulatus plsC316 or olsA gene products supported growth at a nonpermissive temperature, exhibited AGPAT activity in vitro, and restored phosphatidic acid biosynthesis. The more vigorous AGPAT activity displayed by PlsC316 suggested that plsC316 encodes the main AGPAT required for glycerophospholipid synthesis in R. capsulatus, while olsA acts as an alternative AGPAT that is specific for ornithine lipid synthesis. This study therefore revealed for the first time that some OlsA enzymes, like the enzyme of R. capsulatus, are bifunctional and involved in both membrane ornithine lipid and glycerophospholipid biosynthesis.

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“…A PA phosphatase activity has been identified from the membrane fraction of Escherichia coli (22), and mutants defective in this activity have been isolated that are defined by the pgpB gene (23)(24)(25). The PA phosphatase activity in pgpB mutants has been measured using the assay conditions described for the conventional Mg 2ϩ -dependent PA phosphatase enzyme (23)(24)(25).…”

Section: It Is Not Yet Clear What Role Dgpp Plays In Lipid Metabolismmentioning

confidence: 99%

The Escherichia coli pgpB Gene Encodes for a Diacylglycerol Pyrophosphate Phosphatase Activity

Dillon

Riedel

et al. 1996

Journal of Biological Chemistry

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We provided genetic and biochemical evidence that supported the conclusion that the product of pgpB gene of Escherichia coli exhibited diacylglycerol pyrophosphate (DGPP) phosphatase activity. DGPP phosphatase activity was absent in pgpB mutant cells and was expressed at high levels in cells carrying the wild-type pgpB gene on a runaway replication plasmid. The pgpB mutant has been primarily characterized by a defect in phosphatidate (PA) phosphatase activity and also exhibits defects in lyso-PA phosphatase and phosphatidylglycerophosphate phosphatase activities. The defective PA phosphatase in the pgpB mutant was shown to be a Mg 2؉ -independent PA phosphatase activity of the DGPP phosphatase enzyme. We characterized DGPP phosphatase activity in membranes from cells overproducing the pgpB gene product. DGPP phosphatase catalyzed the dephosphorylation of the ␤ phosphate of DGPP to form PA followed by the dephosphorylation of PA to form diacylglycerol. The specificity constant (V max /K m ) for DGPP was 9.3-fold greater than that for PA. The pH optimum for the DGPP phosphatase reaction was 6.5. Activity was independent of a divalent cation requirement, was potently inhibited by Mn 2؉ ions, and was insensitive to inhibition by N-ethylmaleimide. Pure DGPP phosphatase from Saccharomyces cerevisiae was shown to be similar to the E. coli DGPP phosphatase in its ability to utilize lyso-PA and phosphatidylglycerophosphate as substrates in vitro.

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Fatty acyl-coA and fatty acyl-acyl carrier protein as acyl donors in the synthesis of lysophosphatidate and phosphatidate in escherichia coli

Cited by 135 publications

References 45 publications

The pgpA and pgpB genes of Escherichia coli are not essential: evidence for a third phosphatidylglycerophosphate phosphatase

The pgpA and pgpB genes of Escherichia coli are not essential: evidence for a third phosphatidylglycerophosphate phosphatase

Rhodobacter capsulatus OlsA Is a Bifunctional Enyzme Active in both Ornithine Lipid and Phosphatidic Acid Biosynthesis

The Escherichia coli pgpB Gene Encodes for a Diacylglycerol Pyrophosphate Phosphatase Activity

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