An ethanol‐inducible MDR ethanol dehydrogenase/acetaldehyde reductase in <i>Escherichia coli</i>

Shafqat, Jawed; Höög, Jan‐Olov; Hjelmqvist, Lars; Oppermann, U.; Ibáñez, Carlos F.; Jörnvall, Hans

doi:10.1046/j.1432-1327.1999.00323.x

Cited by 47 publications

(29 citation statements)

References 34 publications

(59 reference statements)

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“…Therefore, we measured the enzymatic activity of pAdhP and found 108 and 126 U* min −1 * mg −1 for ethanol and propanol substrates, respectively. These values are in the range of reported activities for alcohol dehydrogenase enzymes from various species [unit: U* min −1 * mg −1 ]: 43 for E. coli, 40-184 for Drosophila melanogaster and 210-7300 for Saccharomyces cerevisiae (Shafqat et al 1999, Blandino et al 1997, Bozcuk et al 2004. Therefore, we concluded that the recombinant protein was active and that its spatial conformation corresponded to that of the native protein.…”

Section: Adhp Effect On Senpssupporting

confidence: 57%

Role of proteins in controlling selenium nanoparticle size

2011

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This work investigates the potential for harnessing the association of bacterial proteins to biogenic selenium nanoparticles (SeNPs) to control the size distribution and the morphology of the resultant SeNPs. We conducted a proteomic study and compared proteins associated with biogenic SeNPs produced by E. coli to chemically synthesized SeNPs as well as magnetite nanoparticles. We identified four proteins (AdhP, Idh, OmpC, AceA) that bound specifically to SeNPs and observed a narrower size distribution as well as more spherical morphology when the particles were synthesized chemically in the presence of proteins. A more detailed study of AdhP (alcohol dehydrogenase propanol-preferring) confirmed the strong affinity of this protein for the SeNP surface and revealed that this protein controlled the size distribution of the SeNPs and yielded a narrow size distribution with a three-fold decrease in the median size. These results support the assertion that protein may become an important tool in the industrial-scale synthesis of SeNPs of uniform size and properties.

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Section: Adhp Effect On Senpssupporting

confidence: 57%

Role of proteins in controlling selenium nanoparticle size

2011

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“…The responsible enzyme turned out to be AdhP, a little-known alcohol dehydrogenase, present in both S. enterica and E. coli, that is known to be induced by ethanol (42). Mutations in this gene were tested because they had previously been seen to contribute to ethanolamine metabolism in certain mutant strains (T. Fazzio, unpublished results).…”

Section: Resultsmentioning

confidence: 99%

Evidence that a Metabolic Microcompartment Contains and Recycles Private Cofactor Pools

2013

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Microcompartments are loose protein cages that encapsulate enzymes for particular bacterial metabolic pathways. These structures are thought to retain and perhaps concentrate pools of small, uncharged intermediates that would otherwise diffuse from the cell. In Salmonella enterica, a microcompartment encloses enzymes for ethanolamine catabolism. The cage has been thought to retain the volatile intermediate acetaldehyde but allow diffusion of the much larger cofactors NAD and coenzyme A (CoA). Genetic tests support an alternative idea that the microcompartment contains and recycles private pools of the large cofactors NAD and CoA. Two central enzymes convert ethanolamine to acetaldehyde (EutBC) and then to acetyl-CoA (EutE). Two seemingly peripheral redundant enzymes encoded by the eut operon proved to be essential for ethanolamine utilization, when subjected to sufficiently stringent tests. These are EutD (acetyl-CoA to acetyl phosphate) and EutG (acetaldehyde to ethanol). Obligatory recycling of cofactors couples the three reactions and drives acetaldehyde consumption. Loss and toxic effects of acetaldehyde are minimized by accelerating its consumption. In a eutD mutant, acetyl-CoA cannot escape the compartment but is released by mutations that disrupt the structure. The model predicts that EutBC (ethanolamine-ammonia lyase) lies outside the compartment, using external coenzyme B 12 and injecting its product, acetaldehyde, into the lumen, where it is degraded by the EutE, EutD, and EutG enzymes using private pools of CoA and NAD. The compartment appears to allow free diffusion of the intermediates ethanol and acetyl-PO 4 but (to our great surprise) restricts diffusion of acetaldehyde.

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“…Further selection using up to 500 mM allyl alcohol failed to yield additional mutants. We also tested a strain with a deletion of the adhP alcohol dehydrogenase (31), but this deletion did not affect ethanol production significantly during glucose fermentation by E. coli ZH88. Effect of yeast extract and pH on coproduction of acetaldehyde and hydrogen.…”

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Coproduction of Acetaldehyde and Hydrogen during Glucose Fermentation by Escherichia coli

Zhu

González

Bobik

2011

Appl Environ Microbiol

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Escherichia coli K-12 strain MG1655 was engineered to coproduce acetaldehyde and hydrogen during glucose fermentation by the use of exogenous acetyl-coenzyme A (acetyl-CoA) reductase (for the conversion of acetylCoA to acetaldehyde) and the native formate hydrogen lyase. A putative acetaldehyde dehydrogenase/acetylCoA reductase from Salmonella enterica (SeEutE) was cloned, produced at high levels, and purified by nickel affinity chromatography. In vitro assays showed that this enzyme had both acetaldehyde dehydrogenase activity (68.07 ؎ 1.63 mol min ؊1 mg ؊1 ) and the desired acetyl-CoA reductase activity (49.23 ؎ 2.88 mol min ؊1 mg ؊1 ). The eutE gene was engineered into an E. coli mutant lacking native glucose fermentation pathways (⌬adhE, ⌬ackA-pta, ⌬ldhA, and ⌬frdC). The engineered strain (ZH88) produced 4.91 ؎ 0.29 mM acetaldehyde while consuming 11.05 mM glucose but also produced 6.44 ؎ 0.26 mM ethanol. Studies showed that ethanol was produced by an unknown alcohol dehydrogenase(s) that converted the acetaldehyde produced by SeEutE to ethanol. Allyl alcohol was used to select for mutants with reduced alcohol dehydrogenase activity. Three allyl alcohol-resistant mutants were isolated; all produced more acetaldehyde and less ethanol than ZH88. It was also found that modifying the growth medium by adding 1 g of yeast extract/liter and lowering the pH to 6.0 further increased the coproduction of acetaldehyde and hydrogen. Under optimal conditions, strain ZH136 converted glucose to acetaldehyde and hydrogen in a 1:1 ratio with a specific acetaldehyde production rate of 0.68 ؎ 0.20 g h ؊1 g ؊1 dry cell weight and at 86% of the maximum theoretical yield. This specific production rate is the highest reported thus far and is promising for industrial application. The possibility of a more efficient "no-distill" ethanol fermentation procedure based on the coproduction of acetaldehyde and hydrogen is discussed.

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An ethanol‐inducible MDR ethanol dehydrogenase/acetaldehyde reductase in Escherichia coli

Cited by 47 publications

References 34 publications

Role of proteins in controlling selenium nanoparticle size

Role of proteins in controlling selenium nanoparticle size

Evidence that a Metabolic Microcompartment Contains and Recycles Private Cofactor Pools

Coproduction of Acetaldehyde and Hydrogen during Glucose Fermentation by Escherichia coli

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