Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0519030 (Klebsiella)
 21,988 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Allitol was produced from D-fructose via a new NADH-regenerating enzymatic reaction system using D-tagatose 3-epimerase (D-TE), ribitol dehydrogenase (RDH), and formate dehydrogenase (FDH). D-fructose was epimerized to D-psicose by the D-TE of Pseudomonas cichorii ST-24 and the D-psicose was subsequently reduced to allitol by the RDH of an RDH-constitutive mutant, X-22, derived from Klebsiella pneumoniae IFO 3321. NADH regeneration for the reduction of D-psicose by the RDH was achieved by the irreversible formate dehydrogenase reaction, which allowed the D-psicose produced from d-fructose to be successively transformed to allitol with a production yield from D-fructose of almost 100%. The reactions progressed without any by-product formation. After separation of the product from the reaction mixture by a simple procedure, a crystal of allitol was obtained in a yield exceeding 90%. This crystal was characterized and determined to be allitol by HPLC analysis, its IR and NMR spectra, its melting point, and optical rotation measurement.
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PMID:Direct production of allitol from D-fructose by a coupling reaction using D-tagatose 3-epimerase, ribitol dehydrogenase and formate dehydrogenase. 1623 7

A 1.4-kbp DNA fragment, including the NADH-linked acetylacetoin reductase/2,3-butanediol dehydrogenase (AACRII/BDH) gene from the chromosomal DNA of Bacillus cereus YUF-4, was cloned in Escherichia coli DH5alpha after its insertion into pUC119, and the resulting plasmid was named pAACRII119. The AACRII/BDH gene had an open reading frame consisting of 1047 bp encoding 349 amino acids. The enzyme exhibited not only AACR activity, but also BDH activity. However, the gene was not located in a 2,3-butanediol (BD) operon, as is the case in the BDH gene of Klebsiella pneumoniae and that of K. terrigena. In addition, there was no BD-cycle-related enzyme gene in the region surrounding the AACRII/BDH gene. The AACR and BDH activities in E. coli DH5alpha/pAACRII119 were 200-fold higher than those in the original B. cereus YUF-4. The characteristics of the AACRII/BDH from E. coli DH 5alpha/pAACRII119 are similar to those of the AACRII/BDH from B. cereus YUF-4. The AACRII/BDH was considered to belong to the NAD(P)- and zinc-dependent long-chain alcohol dehydrogenase (group I ADH) family on the basis of the following distinctive characteristics: it possessed 14 strictly conserved residues of microbial group I ADH and consisted of about 350 amino acids. The enzymatic and genetic characteristics of AACRII/BDH were completely different from those of BDHs belonging to the short-chain dehydrogenase/reductase family. These findings indicated that the AACRII/BDH could be considered a new type of BDH.
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PMID:Characterization of the NADH-linked acetylacetoin reductase/2,3-butanediol dehydrogenase gene from Bacillus cereus YUF-4. 1623 36

Addition of 5 mM: fumarate to cultures of Klebsiella pneumoniae enhanced the rate of glycerol consumption and the production of 1,3-propanediol (PDO). Compared to the control, the activity of glycerol dehydrogenase increased by 35, 33 and 46%, the activity of glycerol dehydratase increased by 160, 210 and 115%, and the activity of 1,3-propanediol oxidoreductase increased by 25, 39 and 85% when, respectively, 5, 15 and 25 mM: fumarate were provided. At the same time, the ratio of NAD+ to NADH decreased by 20, 23 and 29%. Using a 5 l bioreactor with 5 mM: fumarate addition, the specific rate of glycerol consumption and the productivity of PDO was 30 mmol/l h and 17 mmol/l h, respectively, both increased by 35% over the control.
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PMID:Enhancement of 1,3-propanediol production by Klebsiella pneumoniae with fumarate addition. 1631 66

The respiratory NADH:quinone oxidoreductase (complex I) (NDH-1) is a multisubunit enzyme that translocates protons (or in some cases Na+) across energy-conserving membranes from bacteria or mitochondria. We studied the reaction of the Na+-translocating complex I from the enterobacterium Klebsiella pneumoniae with N,N'-dicyclohexylcarbodiimide (DCCD), with the aim of identifying a subunit critical for Na+ binding. At low Na+ concentrations (0.6 mM), DCCD inhibited both quinone reduction and Na+ transport by NDH-1 concurrent with the covalent modification of a 30-kDa polypeptide. In the presence of 50 mM Na+, NDH-1 was protected from inhibition by DCCD, and the modification of the 30-kDa polypeptide with [14C]DCCD was prevented, indicating that Na+ and DCCD competed for the binding to a critical carboxyl group in NDH-1. The 30-kDa polypeptide was assigned to NuoH, the homologue of the ND1 subunit from mitochondrial complex I. It is proposed that Na+ binds to the NuoH subunit during NADH-driven Na+ transport by NDH-1.
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PMID:Specific modification of a Na+ binding site in NADH:quinone oxidoreductase from Klebsiella pneumoniae with dicyclohexylcarbodiimide. 1662 19

Production of 1,3-propanediol (1,3-PD) from glycerol by Klebsiella pneumoniae is restrained by ethanol formation. The first step in the formation of ethanol from acetyl-CoA is catalyzed by aldehyde dehydrogenase (ALDH), an enzyme that competes with 1,3-PD oxidoreductase for the cofactor NADH. This study aimed to improve the production of 1,3-PD by engineering the ethanol formation pathway. An inactivation mutation of the aldA gene encoding ALDH in K. pneumoniae YMU2 was generated by insertion of a tetracycline resistance marker. Inactivation of ALDH resulted in a nearly abolished ethanol formation but a significantly improved 1,3-PD production. Metabolic flux analysis revealed that a pronounced redistribution of intracellular metabolic flux occurred. The final titer, the productivity of 1,3-PD and the yield of 1,3-PD relative to glycerol of the mutant strain reached 927.6 mmol L(-1), 14.05 mmol L(-1)h(-1) and 0.699 mol mol(-1), respectively, which were much higher than those of the parent strain. In addition, the specific 1,3-PD-producing capability (1,3-PD produced per gram of cells) of the mutant strain was 2-fold that of the parent strain due to a lower growth yield of the mutant. By increasing NADH availability, this study demonstrates an important metabolic engineering approach to improve the efficiency of oxidoreduction-coupled bioprocesses.
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PMID:Inactivation of aldehyde dehydrogenase: a key factor for engineering 1,3-propanediol production by Klebsiella pneumoniae. 1693 Oct 85

The inhibition of the cyanide (KCN)-insensitive respiration of Klebsiella oxytoca SYSU-011 by 8-hydroxyquinoline (8-HQ) was determined. Results showed that the profile of the rate of oxygen uptake of normal-grown and 8-HQ-grown K. oxytoca SYSU-011 was biphasic and similar, suggesting that 8-HQ did not inhibit the respiration of normal-grown K. oxytoca SYSU-011. A different biphasic KCN inhibition profile of respiration was observed for KCN-grown cells treated with and without 8-HQ. No decrease in respiration rate of KCN-grown cells and a 40% decrease in respiration rate of KCN-grown cells treated with 8-HQ were observed when KCN concentration was 10(-1) mM. Comparing differences of the profiles of oxygen uptake in KCN-grown cells with and without 8-HQ addition indicated that 8-HQ inhibited expression of the KCN-insensitive pathway carried out by nonheme oxidase. Greater inhibition of NADH oxidase activity by 2-n-heptyl-4-hydroxyquinoline-N-oxide from the cell membrane of the KCN-grown cells treated with 8-HQ, and more H2O2 production from these cells with than without 8-HQ, suggest that the function of the cyanide-insensitive pathway can stabilize the respiration of the cyanide-grown cells to prevent the production of H2O2.
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PMID:Inhibition of cyanide-insensitive respiration in Klebsiella oxytoca SYSU-011 by 8-hydroxyquinolone. 1727 8

Glycerol can be converted to 1,3-propanediol by the anaerobic fermentation of Klebsiella pneumoniae, during which reducing equivalent NADH was consumed. Therefore, the availability of NADH would be critical for the yield of 1, 3-propanediol. In this paper, formate/formate dehydrogenase system was used for the regeneration of in vivo NADH and the improvement of 1, 3-propanediol production. Formate Dehydrogenase gene (fdh) was amplified from Candida boidinii genome by PCR and the purified PCR product was inserted into the vector pMD18-T Simple to construct plasmid pMD18-T Simple-fdh, which was transformed into Escherichia coli DH5alpha and recombinants were selected by blue-white selection. From the transformant the fdh gene was separated and inserted into pMALTM-p2X to construct expression vector pMAL-p2X-fdh, which was transformed into Klebsiella pneumoniae YMU2 and a recombinant strain Klebsiella pneumoniae F-l was obtained. The plasmid stability of strain F-l and the conditions of fdh expression induced by IPTG were studied. It was demonstrated that the plasmid had good stability, and 0.5mmol/L IPTG would induce the expression of protein encoded by fdh gene with the molecular weight of 40.2kDa. The enzyme activity reached 5.47U/mg crude protein when K. pneumoniae F-I was induced for 4h by 0.5mmol/L IPTG. Compared with that of the parent strain K. pneumoniae YMU2, the yield of 1,3-propanediol of recombinant strain F-1 increased by 12.5% in the anaeribic bioreactor.
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PMID:[Expression and characterization of formate dehydrogenase gene in Klebisella pneumoniae]. 1743 26

The expression of genes encoding sodium-translocating NADH:quinone oxidoreductase (Na(+)-NQR) was studied in the marine bacterium Vibrio harveyi and in the enterobacterium Klebsiella pneumoniae. It has been shown that such parameters as NaCl concentration, pH value, and presence of an uncoupler in the growth media do not influence significantly the level of nqr expression. However, nqr expression depends on the growth substrates used by these bacteria. Na(+)-NQR is highly repressed in V. harveyi during anaerobic growth, and nqr expression is modulated by electron acceptors and values of their redox potentials. The latter effect was shown to be independent of the ArcAB regulatory system.
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PMID:Regulation of expression of Na+ -translocating NADH:quinone oxidoreductase genes in Vibrio harveyi and Klebsiella pneumoniae. 1755 13

A soil bacterium capable of metabolizing organophosphorus compounds by reducing the P S group in the molecules was taxonomically identified as Klebsiella sp. strain F51-1-2. The gene involved in the reduction of organophosphorus compounds was cloned from this strain by the shotgun technique, and the deduced protein (named AKR5F1) showed homology to members of the aldo-keto reductase (AKR) superfamily. The intact coding region for AKR5F1 was subcloned into vector pET28a and overexpressed in Escherichia coli BL21(DE3). Recombinant His(6)-tagged AKR5F1 was purified in one step using Ni-nitrilotriacetic acid affinity chromatography. Assays for cofactor specificity indicated that reductive transformation of organophosphorus compounds by the recombinant AKR5F1 specifically required NADH. The kinetic constants of the purified recombinant AKR5F1 toward six thion organophosphorus compounds were determined. For example, the K(m) and k(cat) values of reductive transformation of malathion by the purified recombinant AKR5F1 are 269.5 +/- 47.0 microM and 25.7 +/- 1.7 min(-1), respectively. Furthermore, the reductive transformation of organophosphorus compounds can be largely explained by structural modeling.
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PMID:Cloning of a novel aldo-keto reductase gene from Klebsiella sp. strain F51-1-2 and its functional expression in Escherichia coli. 1757 4

The knowledge of the mechanism of flux distribution will benefit understanding cell physiology and regulation of metabolism. In this study, the measured fluxes obtained under steady-state conditions were used to estimate intracellular fluxes and identify the robustness of branch points of the anaerobic glycerol metabolism in Klebsiella pneumoniae for the production of 1,3-propanediol by metabolic flux analysis. The biomass concentration increased as NADH(2)/NAD(+) decreased at low initial concentration and inversed at high initial glycerol concentration. The flux distribution revealed that the branch points of glycerol and dihydroxyacetonephosphate were rigid to the environmental conditions. However, the pyruvate and acetyl coenzyme A metabolisms gave cells the flexibility to regulate the energy and intermediate fluxes under various environmental conditions. Additionly, it was found that the formation rate of ethanol and the ratio of pyruvate dehydrogenase to pyruvate formate lyase appeared visible fluctuations at high glycerol uptake rate.
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PMID:Metabolic flux and robustness analysis of glycerol metabolism in Klebsiella pneumoniae. 1771 93


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