Microbial Polythioesters

Lütke‐Eversloh, Tina; Steinbüchel, Alexander

doi:10.1002/mabi.200300084

Cited by 38 publications

(41 citation statements)

References 44 publications

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“…This clearly demonstrated that WS/ DGAT is capable of catalyzing not only oxo ester bond formation but also thio ester bond formation. In analogy, bacterial PHA synthases catalyzing the biosynthesis of PHA are also capable of utilizing the sulfur analogues of their natural substrates, which are short-and medium-chain-length 3-hydroxyacyl-CoAs, resulting in polythioester biosynthesis (15). Furthermore, it was recently shown that lipases are able to biosynthesize thio wax esters (28) and polythioesters, respectively (8).…”

Section: Discussionmentioning

confidence: 99%

Thio Wax Ester Biosynthesis Utilizing the Unspecific Bifunctional Wax Ester Synthase/Acyl Coenzyme A:Diacylglycerol Acyltransferase of Acinetobacter sp. Strain ADP1

Uthoff

Stöveken

Weber

et al. 2005

Appl Environ Microbiol

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The bifunctional wax ester synthase/acyl coenzyme A (acyl-CoA):diacylglycerol acyltransferase (WS/DGAT) from Acinetobacter sp. strain ADP1 (formerly Acinetobacter calcoaceticus ADP1) mediating the biosyntheses of wax esters and triacylglycerols was used for the in vivo and in vitro biosynthesis of thio wax esters and dithio wax esters. For in vitro biosynthesis, 5His 6 WS/DGAT comprising an N-terminal His 6 tag was purified from the soluble protein fraction of Escherichia coli Rosetta(DE3)pLysS (pET23a::5His 6 atf). By employing SP-Sepharose high-pressure and Ni-nitrilotriacetic acid fast-protein liquid chromatographies, a 19-fold enrichment with a final specific activity of 165.2 nmol mg of protein ؊1 min ؊1 was achieved by using 1-hexadecanol and palmitoyl-CoA as substrates. Incubation of purified 5His 6 WS/DGAT with 1-hexadecanethiol and palmitoylCoA as substrates resulted in the formation of palmitic acid hexadecyl thio ester (10.4% relative specific activity of a 1-hexadecanol control). Utilization of 1,8-octanedithiol and palmitoyl-CoA as substrates led to the formation of 1-S-monopalmitoyloctanedithiol and minor amounts of 1,8-S-dipalmitoyloctanedithiol (59.3% relative specific activity of a 1-hexadecanol control). The latter dithio wax ester was efficiently produced when 1-S-monopalmitoyloctanedithiol and palmitoyl-CoA were used as substrates (13.4% specific activity relative to that of a 1-hexadecanol control). For the in vivo biosynthesis of thio wax esters, the knockout mutant Acinetobacter sp. strain ADP1acr1⍀Km, which is unable to produce fatty alcohols, was used. Cultivation of Acinetobacter sp. strain ADP1acr1⍀Km in the presence of gluconate, 1-hexadecanethiol, and oleic acid in nitrogen-limited mineral salts medium resulted in the accumulation of unusual thio wax esters that accounted for around 1.19% (wt/wt) of the cellular dry weight and consisted mainly of oleic acid hexadecyl thioester as revealed by gas chromatography-mass spectrometry.Polyhydroxyalkanoic acids (PHA) in bacteria represent the most abundant group of neutral storage lipids, which serve as intracellular carbon and energy storage compounds (23). In addition, triacylglycerols (TAGs) and wax esters also occur as bacterial storage lipids, though at a much lower frequency than in eukaryotic microorganisms (22). Significant TAG accumulation was found, particularly in species belonging to the class Actinomycetes (1), as was reported for the genera Mycobacterium (3), Nocardia, and Streptomyces (2). TAGs are synthesized by the acyl coenzyme A (acyl-CoA):diacylglycerol acyltransferase (DGAT) (13), which catalyzes the esterification of diacylglycerol with long-chain acyl-CoA. Wax esters are oxoesters of primary long-chain fatty alcohols and long-chain fatty acids. Occurrence of wax esters has been frequently reported for various Acinetobacter species (6). Under growthlimiting conditions, Acinetobacter calcoaceticus accumulates wax esters intracellularly as insoluble inclusions. The chemical structure of the wax esters synthesized by A. ca...

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Section: Discussionmentioning

confidence: 99%

Thio Wax Ester Biosynthesis Utilizing the Unspecific Bifunctional Wax Ester Synthase/Acyl Coenzyme A:Diacylglycerol Acyltransferase of Acinetobacter sp. Strain ADP1

Uthoff

Stöveken

Weber

et al. 2005

Appl Environ Microbiol

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“…The molecular masses of PHA polymers can range from 50 to 1,000 kDa or even above, and they may exhibit variable physical properties according to their monomer composition (244,245). The lack of specificity of PHA synthases is further underlined by their ability to synthesize polythioesters (PTE) by generating thioester bonds between 3-mercaptopropionic acid or other thiolic compounds (246,247).…”

Section: Pha Synthasesmentioning

confidence: 99%

Acyltransferases in Bacteria

Röttig

Steinbüchel

2013

Microbiol Mol Biol Rev

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151

141

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SUMMARY Long-chain-length hydrophobic acyl residues play a vital role in a multitude of essential biological structures and processes. They build the inner hydrophobic layers of biological membranes, are converted to intracellular storage compounds, and are used to modify protein properties or function as membrane anchors, to name only a few functions. Acyl thioesters are transferred by acyltransferases or transacylases to a variety of different substrates or are polymerized to lipophilic storage compounds. Lipases represent another important enzyme class dealing with fatty acyl chains; however, they cannot be regarded as acyltransferases in the strict sense. This review provides a detailed survey of the wide spectrum of bacterial acyltransferases and compares different enzyme families in regard to their catalytic mechanisms. On the basis of their studied or assumed mechanisms, most of the acyl-transferring enzymes can be divided into two groups. The majority of enzymes discussed in this review employ a conserved acyltransferase motif with an invariant histidine residue, followed by an acidic amino acid residue, and their catalytic mechanism is characterized by a noncovalent transition state. In contrast to that, lipases rely on completely different mechanism which employs a catalytic triad and functions via the formation of covalent intermediates. This is, for example, similar to the mechanism which has been suggested for polyester synthases. Consequently, although the presented enzyme types neither share homology nor have a common three-dimensional structure, and although they deal with greatly varying molecule structures, this variety is not reflected in their mechanisms, all of which rely on a catalytically active histidine residue.

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“…PTE homopolymers are synthesized by applying the artificial BPEC pathway in the recombinant Escherichia coli strain JM109(pBPP1) (7). Therefore, 3MP, 3-mercaptobutyrate (3MB), or 3-mercaptovalerate (3MV) is applied as a precursor substrate (7,8). Only recently, the production of PTE homopolymers in Advenella mimigardefordensis DPN7…”

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confidence: 99%