PMID(sorted ascending)
the biology of zymomonas. 197716585
distribution of the phosphoenolpyruvate:glucose phosphotransferase system in fermentative bacteria.a number of selected fermentative bacteria were surveyed for the presence of the phosphoenolpyruvate:glucose phosphotransferase system, with particular attention to those organisms which ferment glucose by pathways other than the embden-meyerhof-parnas pathway. the phosphoenolpyruvate:glusoe phosphotransferase system was found in all homofermentative lactic acid bacteria tested that ferment glucose via the embden-meyerhof-parnas pathway, but in none of a group of heterofermentative species of la ...1979457606
photoassimilation of acetate and metabolism of carbohydrate in chlorobium thiosulfatophilum.1. washed cell suspensions of chlorobium thiosulfatophilium form large amounts of a polyglucose in the light. addition of acetate to the cells increases the formation of polysaccharide considerable. during incubation in the dark, polysaccharide decreases with time, and organic acids such as succinic and propionic acid are excreted into the medium. 2. glucose isolated from cells which had photoassimilated 1-, 2-, and u-14c-acetate had a specific activity which lay between 1 and 2 times that of th ...1975808188
identification and grouping of bacteria by numerical analysis of their electrophoretic protein patterns.improved methods for the identification and grouping of bacteria by polyacrylamide gel electrophoresis of soluble proteins are described. electrophoretic protein patterns were obtained in rigorously standardized comditions. the results were much more reproducible than any described previously. some of the factors affecting reproducibility were; growth conditions, time and speed of centrifugation of extracts, and conditions of gel electrophoresis. protein patterns were compared by computing corre ...19751141858
cloning, sequencing, and expression of the zymomonas mobilis fructokinase gene and structural comparison of the enzyme with other hexose kinases.the frk gene encoding the enzyme fructokinase (fructose 6-phosphotransferase [ec]) from zymomonas mobilis has been isolated on a partial taqi digest fragment of the genome and sequenced. an open reading frame of 906 bp corresponding to 302 amino acids was identified on a 3-kbp taqi fragment. the deduced amino acid sequence corresponds to the first 20 amino acids (including an n-terminal methionine) determined by amino acid sequencing of the purified protein. the 118 bp preceding the meth ...19921317376
immunocytochemical localization of glycolytic and fermentative enzymes in zymomonas antibodies were used to examine the subcellular locations of 11 glycolytic and fermentative enzymes in zymomonas mobilis. glucose-fructose oxidoreductase was clearly localized in the periplasmic region. phosphogluconate lactonase and alcohol dehydrogenase i were concentrated in the cytoplasm near the plasma membrane. the eight remaining enzymes were more evenly distributed within the cytoplasmic matrix. selected enzyme pairs were labeled on opposite sides of the same thin section to ...19921320611
mechanism of glutamate uptake in zymomonas mobilis.the energetics of the anaerobic gram-negative bacterium zymomonas mobilis, a well-known ethanol-producing organism, is based solely on synthesis of 1 mol of atp per mol of glucose by the entner-doudoroff pathway. when grown in the presence of glucose as a carbon and energy source, z. mobilis had a cytosolic atp content of 3.5 to 4 mm. because of effective ph homeostasis, the components of the proton motive force strongly depended on the external ph. at ph 5.5, i.e., around the optimal ph for gro ...19921332937
cloning and characterization of a gene from bacillus stearothermophilus var. non-diastaticus encoding a glycerol dehydrogenase.a 4.1-kb ecori fragment which includes the gene (glda) encoding a glycerol dehydrogenase (g1dh; ec; glycerol:nad oxidoreductase) from bacillus stearothermophilus var. non-diastaticus has been cloned by virtue of its ability to restore glycerol utilisation to escherichia coli glycerol kinase (glpk) and glycerol-3-phosphate dehydrogenase (glpd) mutants. sequencing suggests that the glda gene is likely to be monocistronic and encodes a protein of 39450 da. the deduced amino acid composition ...19921339360
cloning and expression in escherichia coli of mercuric ion resistance coding genes from zymomonas mobilis.from a genomic library of zymomonas mobilis prepared in escherichia coli, two clones (carrying pzh4 and pzh5) resistant to the mercuric ion were isolated. on partial restriction analysis these two clones appeared to have the same 2.9 kb insert. mercuric reductase activity was assayed from the escherichia coli clone carrying pzh5 and it was hg(2+)-inducible, nadh dependent and also required 2-mercaptoethanol for its activity. the plasmid pzh5 encoded three polypeptides, mercuric reductase (mera; ...19911367242
effective diffusivity of galactose in calcium alginate gels containing immobilized zymomonas mobilis.the effective diffusivity of galactose was measured for calcium alginate gel membranes containing immobilized live zymomonas mobilis cells at concentrations ranging from 0 to 150 g dry wt/l of gel. since galactose is not taken up by living z. mobilis organisms, the diffusion of this representative six-carbon sugar could be studied independently of sugar consumption. various immobilized biomass loadings were achieved by two different techniques: addition of biomass at known concentrations to the ...19921368005
differential salt-promoted chromatography for protein purification.a range of hydrophobic-type adsorbents for protein chromatography has been screened for the binding, at high salt concentrations, of 10 enzymes from a bacterial extract. adsorbents were chosen for tandem chromatography, in which the first adsorbent removed much of the protein, and the second and subsequent columns bound the desired enzymes. simple schemes for isolating zymomonas mobilis and yeast alcohol dehydrogenases are described, in which the enzymes are affinity eluted by nad+.19901368158
cloning, sequencing, and characterization of the intracellular invertase gene from zymomonas mobilis.the structural gene for the intracellular invertase e1 of zymomonas mobilis strain z6c was cloned in a 2.25-kb dna fragment on push11, and expressed in escherichia coli hb101. the enzyme produced by the e. coli carrying push11 was purified about 1,122 fold to homogenicity with a yield of 4%. the molecular weight and substrate specificity of the enzyme were identical with those of the intracellular invertase e1 from z. mobilis. the nucleotides of the cloned dna were sequenced; they included an op ...19911368686
the use of multifunctional adsorbents to purify membrane-bound phosphatases from zymomonas mobilis. purification of acid phosphatase, alkaline phosphatase and atpase.the purification of detergent-solubilized membrane-bound phosphatases from zymomonas mobilis using novel adsorbents is described. the prepared adsorbents have a hydrophobic core with functional groups attached. these functional groups may either increase or decrease the hydrophobicity of the adsorbent, or participate in other forms of interactions. adsorption of acid phosphatase (acp), alkaline phosphatase (alp) and atpase to these adsorbents was salt-promoted. desorption was achieved by decreas ...19911368773
characterization of zymomonas mobilis alkaline phosphatase activity in escherichia coli.zymomonas mobilis phoa gene encoding alkaline phosphatase was expressed in escherichia coli cc118 carrying the recombinant plasmid pzap1. the ph optimum for this enzyme was 9.0 and showed a peak activity at 42 degrees c. this enzyme required zn2+ for its catalytic activity; however, mg2+ or ca2+ significantly affected the activity. this enzyme was found to be ethanolabile, and ethanol inhibition was reversed by addition of zn2+. kinetics of z. mobilis alkaline phosphatase production in e. coli c ...19921369189
cloning and expression in escherichia coli of an alkaline phosphatase (phoa) gene from zymomonas alkaline phosphatase (phoa) gene from zymomonas mobilis was isolated in escherichia coli cc118 by use of the plasmid bluescript ks+. the origin of the 6.4-kb dna fragment in pzap1 from the chromosome of z. mobilis was confirmed by southern blotting and hybridization studies. the z. mobilis phoa gene was localized at one end of the chromosomal insert on plasmid pzap1. the z. mobilis phoa gene was expressed from its own promoter in e. coli, and the enzyme was localized to the periplasmic space. ...19921369200
the entner-doudoroff pathway: history, physiology and molecular biology.the entner-doudoroff pathway is now known to be very widely distributed in nature. biochemical and physiological studies show that the entner-doudoroff pathway can operate in a linear and catabolic mode, in a 'cyclic' mode, in a modified mode involving non-phosphorylated intermediates, or in alternative modes involving c1 metabolism and anabolism. molecular and genetic analyses of the entner-doudoroff pathway in zymomonas mobilis, escherichia coli and pseudomonas aeruginosa have led to an improv ...19921389313
coordination of expression of zymomonas mobilis glycolytic and fermentative enzymes: a simple hypothesis based on mrna stability.although zymomonas mobilis is prototrophic, glycolytic and fermentative enzymes (ethanologenic enzymes) constitute over half of the cytoplasmic protein. in this study, transcript stability, functional message pools, and the abundance of cytoplasmic products were compared for genes encoding eight of these essential enzymes. the transcripts of all were very stable, with half-lives ranging from 8 to 18 min. this transcript stability is proposed as an important feature in z. mobilis that may disting ...19921400196
molecular characterization of the zymomonas mobilis enolase (eno) gene.the zymomonas mobilis gene encoding enolase was cloned by genetic complementation of an escherichia coli eno mutant. an enzyme assay and sodium dodecyl sulfate-polyacrylamide gel electrophoresis confirmed the overexpression of enolase in e. coli clones carrying the z. mobilis eno gene. the eno gene is present in a single copy of the z. mobilis genome. nucleotide sequence analysis of the eno region revealed an open reading frame of 1,293 bp that encodes a protein of 428 amino acids with a predict ...19921400207
use of the tac promoter and laciq for the controlled expression of zymomonas mobilis fermentative genes in escherichia coli and zymomonas mobilis.the zymomonas mobilis genes encoding alcohol dehydrogenase i (adha), alcohol dehydrogenase ii (adhb), and pyruvate decarboxylase (pdc) were overexpressed in escherichia coli and z. mobilis by using a broad-host-range vector containing the tac promoter and the laciq repressor gene. maximal iptg (isopropyl-beta-d-thiogalactopyranoside) induction of these plasmid-borne genes in z. mobilis resulted in a 35-fold increase in alcohol dehydrogenase i activity, a 16.7-fold increase in alcohol dehydrogena ...19921429459
cloning and expression in escherichia coli of a phoa gene encoding a phosphate-irrepressible alkaline phosphatase of zymomonas mobilis.the zymomonas mobilis phoa gene, encoding a phosphate-irrepressible alkaline phosphatase (zapase), was cloned and its expression was studied in phoa mutants of escherichia coli. the zapase was recovered in the soluble fraction of e. coli. the enzyme was synthesized constitutively and its synthesis not repressed by phosphate, unlike the phoa gene of e. coli. the phoa gene of z. mobilis was mutagenized by mini mu pr13 and the mutated gene crossed into z. mobilis in order to obtain phoa mutants by ...19921459397
isolation and characterization of the gene encoding gluconolactonase from zymomonas mobilis.the gene encoding the enzyme gluconolactonase (d-glucono-delta-lactone lactonohydrolase, ec has been isolated from a recombinant library of genomic zymomonas mobilis dna, by detection of enzyme activity in recombinant clones. the gene encoded a protein of 320 amino acids, which is processed to the mature enzyme of 285 amino acids (31079 da) by cleavage at an ala-ala bond, as determined from n-terminal sequencing of the purified enzyme. a minor sequence commencing at amino acid 6 is sug ...19921482681
broad host range plasmids carrying the escherichia coli lactose and galactose operons.we have developed a number of broad-host-range plasmids that allow the expression of the escherichia coli lac operon from any cloned promoter, and the creation of 'in phase' fusions between lacz and other cloned genes. in a second series of constructions, the e. coli gal operon has been cloned into the broad-host-range vector and a plasmid carrying both the e. coli gal and lac genes is described. these plasmids have been transferred into pseudomonas aeruginosa and zymomonas mobilis and their eff ...19921526459
cloning and molecular characterization of the dna ligase gene (lig) from zymomonas mobilis.the zymomonas mobilis lig gene that encodes dna ligase was cloned from a cosmid library and identified by genetic complementation of a conditional-lethal escherichia coli dna ligase mutant. nucleotide sequence analysis of the z. mobilis lig region indicated that the gene is 2196 bp long, encoding a protein with a deduced molecular mass of 82,089. the primary amino acid sequence of the z. mobilis ligase is 48% identical to the e. coli enzyme. two genes located upstream of lig were identified as t ...19921526462
cloning, sequence analysis, and expression of the structural gene encoding glucose-fructose oxidoreductase from zymomonas mobilis.the gene encoding glucose-fructose oxidoreductase (gfo) from zymomonas mobilis was cloned in escherichia coli and sequenced. an open reading frame of 439 amino acids encoded a protein of 49 kda. a leader sequence of 52 amino acids preceded the n-terminal sequence of the enzyme, indicating cleavage of the precursor protein at an ala-ala site to give rise to an active form of the enzyme of 43 kda. processing of the glucose-fructose oxidoreductase leader sequence, although not complete, was demonst ...19921537789
the zymomonas mobilis glf, zwf, edd, and glk genes form an operon: localization of the promoter and identification of a conserved sequence in the regulatory region.the zymomonas mobilis genes that encode the glucose-facilitated diffusion transporter (glf), glucose-6-phosphate dehydrogenase (zwf), 6-phosphogluconate dehydratase (edd), and glucokinase (glk) are clustered on the genome. the data presented here firmly establish that the glf, zwf, edd, and glk genes form an operon, in that order. the four genes of the operon are cotranscribed on a 6.14-kb mrna. the site of transcriptional initiation for the polycistronic message was mapped by primer extension a ...19921569013
the polycistronic mrna of the zymomonas mobilis glf-zwf-edd-glk operon is subject to complex transcript processing.the full-length 6.14-kb polycistronic glf-zwf-edd-glk mrna from zymomonas mobilis appears to be processed by endonucleolytic cleavage, resulting in the formation of several discrete transcripts. northern analysis and transcript mapping revealed that the processed transcripts correspond to functional mono-, di-, or tricistronic messages. the relative abundance of the gene-specific, functional messages was measured. expression of zwf and edd correlated well with functional message levels. dispropo ...19921569014
changes in the fluorescence of bound nucleotide during the reaction catalysed by glucose-fructose oxidoreductase from zymomonas mobilis.the reduction of gluconolactone by glucose-fructose oxidoreductase containing tightly bound nadph (enzyme-nadph) is biphasic in nucleotide fluorescence. the initial rapid decrease, which represents quenching of the fluorescence by bound lactone, is followed by a slower decrease which corresponds to the change in absorbance. at low glucose concentrations, the oxidation of glucose by enzyme-nadp+ involves a single first-order process with similar rate constants in fluorescence and absorbance. at h ...19921572370
purification and primary structure of pyruvate decarboxylase from zymomonas mobilis.pyruvate decarboxylase (e.c., the key enzyme in the glycolytic pathway to ethanol, was isolated in gram amounts from zymomonas mobilis for structural studies. the primary structure was determined by automated edman degradation and compared with that deduced from the dna sequence of the structural gene, previously published by two groups (a. d. neale, r. k. scopes, r. e. h. wettenhall, and n. j. hoogenraad, 1987, nucleic acids res. 15, 1753-1761; m. reynen, and h. sahm, 1988, j. bacterio ...19921586459
purification and characterization of pyruvate decarboxylase from sarcina ventriculi.pyruvate decarboxylase from the obligate anaerobe sarcina ventriculi was purified eightfold. the subunit mr was 57,000 +/- 3000 as estimated from sds-page, and the native mr estimated by gel filtration on a superose 6 column was 240,000, indicating that the enzyme is a tetramer. the mr values are comparable to those for pyruvate decarboxylase from zymomonas mobilis and saccharomyces cerevisiae, which are also tetrameric enzymes. the enzyme was oxygen stable, and had a ph optimum within the range ...19921588311
effect of acetic acid on xylose conversion to ethanol by genetically engineered e. coli.efficient utilization of the pentosan fraction of hemicellulose from lignocellulosic feedstocks offers an opportunity to increase the yield and to reduce the cost of producing fuel ethanol. during prehydrolysis (acid hydrolysis or autohydrolysis of hemicellulose), acetic acid is formed as a consequence of the deacetylation of the acetylated moiety of hemicellulose. recombinant escherichia coli b (atcc 11303), carrying the plasmid plo1297 with pyruvate decarboxylase and alcohol dehydrogenase ii g ...19921622203
molecular characterization of the entner-doudoroff pathway in escherichia coli: sequence analysis and localization of promoters for the edd-eda operon.the nucleotide sequence of the entire escherichia coli edd-eda region that encodes the enzymes of the entner-doudoroff pathway was determined. the edd structural gene begins 236 bases downstream of zwf. the eda structural gene begins 34 bases downstream of edd. the edd reading frame is 1,809 bases long and encodes the 602-amino-acid, 64,446-da protein 6-phosphogluconate dehydratase. the deduced primary amino acid sequences of the e. coli and zymomonas mobilis dehydratase enzymes are highly conse ...19921624451
inhibition of transketolase and pyruvate decarboxylase by omeprazole.omeprazole inhibited two thiamin diphosphate-dependent enzymes, pyruvate decarboxylase (ec, pdc) from zymomonas mobilis and transketolase (ec, tk) from human erythrocytes. inhibition of pdc was competitive with the coenzyme with a ki value of 42 +/- 3 microm, whereas inhibition of tk was complex.19921632833
artificial neural networks in bioprocess state estimation.the application of artificial neural networks to the estimation and prediction of bioprocess variables is presented in this paper. a neural network methodology is discussed, which uses environmental and physiological information available from on-line sensors, to estimate concentration of species in the bioreactor. two case studies are presented, both based on the ethanol production by zymomonas mobilis. an efficient optimization algorithm which reduces the number of iterations required for conv ...19921636477
ethanol production from cellobiose, amorphous cellulose, and crystalline cellulose by recombinant klebsiella oxytoca containing chromosomally integrated zymomonas mobilis genes for ethanol production and plasmids expressing thermostable cellulase genes from clostridium thermocellum.the zymomonas mobilis genes for ethanol production have been integrated into the chromosome of klebsiella oxytoca m5a1. the best of these constructs, strain p2, produced ethanol efficiently from cellobiose in addition to monomeric sugars. utilization of cellobiose and cellotriose by this strain eliminated the requirement for external beta-glucosidase and reduced the amount of commercial cellulase needed to ferment solka floc sw40 (primarily crystalline cellulose). the addition of plasmids encodi ...19921637151
segmental message stabilization as a mechanism for differential expression from the zymomonas mobilis gap zymomonas mobilis, three- to fourfold more glyceraldehyde-3-phosphate dehydrogenase protein than phosphoglycerate kinase is needed for glycolysis because of differences in catalytic efficiency. consistent with this requirement, higher levels of glyceraldehyde-3-phosphate dehydrogenase were observed with two-dimensional polyacrylamide gel electrophoresis. the genes encoding these enzymes (gap and pgk, respectively) form a bicistronic operon, and some form of regulation is required to provide t ...19911702780
cloning, characterization, and nucleotide sequence analysis of a zymomonas mobilis phosphoglucose isomerase gene that is subject to carbon source-dependent regulation.the zymomonas mobilis gene encoding phosphoglucose isomerase (pgi) was cloned by genetic complementation of an escherichia coli pgi mutant. an enzyme assay and sodium dodecyl sulfate-polyacrylamide gel electrophoresis confirmed the presence of excess amounts of phosphoglucose isomerase in e. coli clones carrying the z. mobilis pgi gene. the pgi gene is present in only one copy on the z. mobilis genome. nucleotide sequence analysis of the pgi region revealed an open reading frame of 1,524 bp prec ...19911708765
effects of substitution of aspartate-440 and tryptophan-487 in the thiamin diphosphate binding region of pyruvate decarboxylase from zymomonas mobilis.a tryptophan residue at position 487 in zymomonas mobilis pyruvate decarboxylase was altered to leucine by site-directed mutagenesis. this modified z. mobilis pyruvate decarboxylase was active when expressed in escherichia coli and had unchanged kinetics towards pyruvate. the enzyme showed a decreased affinity for the cofactors with the half-saturating concentrations increasing from 0.64 to 9.0 microm for thiamin diphosphate and from 4.21 to 45 microm for mg2+. unlike the wild-type enzyme, there ...19921730299
metabolic engineering of klebsiella oxytoca m5a1 for ethanol production from xylose and glucose.the efficient diversion of pyruvate from normal fermentative pathways to ethanol production in klebsiella oxytoca m5a1 requires the expression of zymomonas mobilis genes encoding both pyruvate decarboxylase and alcohol dehydrogenase. final ethanol concentrations obtained with the best recombinant, strain m5a1 (ploi555), were in excess of 40 g/liter with an efficiency of 0.48 g of ethanol (xylose) and 0.50 g of ethanol (glucose) per g of sugar, as compared with a theoretical maximum of 0.51 g of ...19911746941
cloning, characterization and expression of the zymononas mobilis eda gene that encodes 2-keto-3-deoxy-6-phosphogluconate aldolase of the entner-doudoroff pathway.the eda gene that encodes 2-keto-3-deoxy-6-phosphogluconate aldolase of the entner-doudoroff pathway was cloned from zymomonas mobilis by genetic complementation of an escherichia coli mutant. the gene is present in a single copy on the z. mobilis genome and is not tightly linked to the edd gene. nucleotide sequence analysis of the eda region revealed that the structural gene is 627 bp long and capable of encoding a protein of 208 amino acids with a deduced molecular weight of 21,505. the eda ge ...19911809834
membrane-associated atpase from zymomonas mobilis; purification and characterization.the major atpase (adenosinetriphosphatase, ec activity present in the membrane of zymomonas mobilis has been isolated, using a novel combination of multifunctional hydrophobic adsorbents. on subjecting the preparation to gel filtration, activity was lost, but could be restored by reconstituting fractions from the column. subunit composition of the fractions indicated that the zymomonas mobilis atpase is of the f0f1 type, and so is probably involved in proton pumping. the contribution of ...19911832963
expression of an l-alanine dehydrogenase gene in zymomonas mobilis and excretion of approach to broaden the product range of the ethanologenic, gram-negative bacterium zymomonas mobilis by means of genetic engineering is presented. gene alad for l-alanine dehydrogenase (ec from bacillus sphaericus was cloned and introduced into z. mobilis. under the control of the strong promoter of the pyruvate decarboxylase (pdc) gene, the enzyme was expressed up to a specific activity of nearly 1 mu mol . min -1 . mg of protein -1 in recombinant cells. as a results of this high ...19911854197
production of beta-carotene in zymomonas mobilis and agrobacterium tumefaciens by introduction of the biosynthesis genes from erwinia uredovora.the erwinia uredovora crtb, crte, crti, and crty genes required for beta-carotene biosynthesis were introduced by conjugal transfer into an ethanol-producing bacterium, zymomonas mobilis, and a phytopathogenic bacterium, agrobacterium tumefaciens, in which no carotenoid is synthesized. the transconjugants of z. mobilis and a. tumefaciens carrying these genes appeared as yellow colonies and produced 220 and 350 micrograms of beta-carotene per g of dry weight, respectively, in the stationary phase ...19911872613
content and composition of hopanoids in zymomonas mobilis under various growth using a new method for quantification of the different hopanoid derivatives, a total hopanoid content of about 30 mg/g (dry cell weight) was observed in zymomonas mobilis. this value is the highest reported for bacteria so far. the major hopanoids in z. mobilis were the ether and glycosidic derivatives of tetrahydroxy-bacteriohopane, constituting about 41 and 49% of the total hopanoids. tetrahydroxybacteriohopane itself, diplopterol, and hopene made up about 6, 3, and 1%, respectively. only m ...19911885538
gel electrophoretic analysis of zymomonas mobilis glycolytic and fermentative enzymes: identification of alcohol dehydrogenase ii as a stress protein.the 13 major enzymes which compose the glycolytic and fermentative pathways in zymomonas mobilis are particularly abundant and represent one-half of the soluble protein in exponential-phase cells. one- and two-dimensional polyacrylamide gel electrophoresis maps were developed for 12 of these enzymes. assignments were made by comigration with purified proteins, comparison with overexpressed genes in recombinant strains, and western blots (immunoblots). although most glycolytic enzymes appeared re ...19911917831
ethanol production by recombinant escherichia coli carrying genes from zymomonas mobilis.efficient utilization of lignocellulosic feedstocks offers an opportunity to reduce the cost of producing fuel ethanol. the fermentation performance characteristics of recombinant escherichia coli atcc 11303 carrying the "pet plasmid" (ploi297) with the lac operon controlling the expression of pyruvate decarboxylase (pdc) and alcohol dehydrogenase ii (adhb) genes cloned from zymomonas mobilis cp4 (alterthum & ingram, 1989) were assessed in batch and continuous processes with sugar mixtures desig ...19911929364
electron microscopic analysis and biochemical characterization of a novel methanol dehydrogenase from the thermotolerant bacillus sp. c1.methanol dehydrogenase from the thermotolerant bacillus sp. c1 was studied by electron microscopy and image processing. two main projections can be distinguished: one exhibits 5-fold symmetry and has a diameter of 15 nm, the other is rectangular with sides of 15 and 9 nm. subsequent image processing showed that the 5-fold view possesses mirror symmetry. the rectangular views can be divided into two separate classes, one of which has 2-fold rotational symmetry. it is concluded that methanol dehyd ...19911995642
molecular cloning of the gene for indolepyruvate decarboxylase from enterobacter cloacae.although indole-3-acetic acid (iaa) is a well-known plant hormone, the main iaa biosynthetic pathway from l-tryptophan (trp) via indole-3-pyruvic acid (ipya) has yet to be elucidated. previous studies have suggested that iaa is produced by enterobacter cloacae isolated from the rhizosphere of cucumbers and its biosynthetic pathway may possibly be the same as that in plants. to elucidate this pathway, the iaa biosynthetic gene was isolated from a genomic library of e. cloacae by assaying for the ...19912034209
pyruvate decarboxylase from zymomonas mobilis. structure and re-activation of apoenzyme by the cofactors thiamin diphosphate and magnesium study the mechanism of re-activation of zymomonas mobilis pyruvate decarboxylase apoenzyme by its cofactors thiamin diphosphate and mg2+, cofactor-free enzyme was prepared by dialysis against 1 mm-dipicolinic acid at ph 8.2. this apoenzyme was then used in a series of experiments that included determination of: (a) the affinity towards one cofactor when the other was present at saturating concentrations; (b) cofactor-binding rates by measuring the quenching of tryptophan fluorescence on the a ...19912049073
genetic improvement of escherichia coli for ethanol production: chromosomal integration of zymomonas mobilis genes encoding pyruvate decarboxylase and alcohol dehydrogenase ii.zymomonas mobilis genes for pyruvate decarboxylase (pdc) and alcohol dehydrogenase ii (adhb) were integrated into the escherichia coli chromosome within or near the pyruvate formate-lyase gene (pfl). integration improved the stability of the z. mobilis genes in e. coli, but further selection was required to increase expression. spontaneous mutants were selected for resistance to high level of chloramphenicol that also expressed high levels of the z. mobilis genes. analogous mutants were selected ...19912059047
determination of hopanoid levels in bacteria using high-performance liquid chromatography.a reverse-phase hplc method to detect and quantify levels of hopanoids in bacteria has been developed. chromophores have been introduced by derivatization and the levels of the c35 hopanoids and their conjugates can be measured in bacterial lipid extracts down to picomole levels. some structural variations of the complex lipids were detected after derivatization and were easily purified using the same hplc system. zymomonas mobilis and rhodospirillum rubrum extracts were examined using this syst ...19902109551
activation of the lac genes of tn951 by insertion sequences from pseudomonas cepacia.we have identified three transposable gene-activating elements from pseudomonas cepacia on the basis of their abilities to increase expression of the lac genes of the broad-host-range plasmid pgc91.14 (prp1::tn951). when introduced into auxotrophic derivatives of p. cepacia 249 (atcc 17616), this plasmid failed to confer the ability to utilize lactose. the lac genes of tn951 were poorly expressed in p. cepacia and were not induced by isopropyl-beta-d-thiogalactopyranoside. lac+ variants of the p ...19902156800
cloning of the zymomonas mobilis structural gene encoding alcohol dehydrogenase i (adha): sequence comparison and expression in escherichia coli.zymomonas mobilis ferments sugars to produce ethanol with two biochemically distinct isoenzymes of alcohol dehydrogenase. the adha gene encoding alcohol dehydrogenase i has now been sequenced and compared with the adhb gene, which encodes the second isoenzyme. the deduced amino acid sequences for these gene products exhibited no apparent homology. alcohol dehydrogenase i contained 337 amino acids, with a subunit molecular weight of 36,096. based on comparisons of primary amino acid sequences, th ...19902185223
behavior of the hybrid plasmid pnsw301 in zymomonas mobilis grown in continuous culture.the stability of the plasmid pnsw301 which was formed by cointegration of the inc w r plasmid sa and the 14.5-kb pnsw1 plasmid of zymomonas mobilis zm6100 was investigated in zm6100(pnsw301) grown in continuous culture without antibiotic selection. the cointegrate plasmid, pnsw301, was found to be structurally unstable and a total reduction in the size of pnsw301 of approximately 21 kb occurred during growth in continuous culture. following a systematic study, a number of deletion derivatives of ...19902217571
construction of expression vectors for the gram-negative bacterium zymomonas mobilis.a set of vectors was constructed for the cloning and expression of heterologous genes in the gram-negative bacterium zymomonas mobilis under the control of the pdc promoter of z. mobilis. the vectors pptz1, pptz3, and pptz4 are based on the cryptic z. mobilis plasmid pzm02 and on parts of the escherichia coli plasmids pkk223-3 and pbr322 together with the multiple cloning site of phage m13mp18. dna fragments can be readily inserted immediately downstream from the pdc promoter at unique restricti ...19902250658
cloning and sequencing of the saca gene: characterization of a sucrase from zymomonas mobilis.the zymomonas mobilis gene (saca) encoding a protein with sucrase activity has been cloned in escherichia coli and its nucleotide sequence has been determined. potential ribosome-binding site and promoter sequences were identified in the region upstream of the gene which were homologous to e. coli and z. mobilis consensus sequences. extracts from e. coli cells, containing the saca gene, displayed a sucrose-hydrolyzing activity. however, no transfructosylation activity (exchange reaction or levan ...19902254250
sequence and genetic organization of a zymomonas mobilis gene cluster that encodes several enzymes of glucose metabolism.the zymomonas mobilis genes that encode glucose-6-phosphate dehydrogenase (zwf), 6-phosphogluconate dehydratase (edd), and glucokinase (glk) were cloned independently by genetic complementation of specific defects in escherichia coli metabolism. the identity of these cloned genes was confirmed by various biochemical means. nucleotide sequence analysis established that these three genes are clustered on the genome and revealed an additional open reading frame in this region that has significant a ...19902254282
nucleotide sequence of the zymomonas mobilis alcohol dehydrogenase ii gene. 19902308827
inactivation of pyruvate decarboxylase by 3-hydroxypyruvate.pyruvate decarboxylase from zymomonas mobilis is inhibited by 3-hydroxypyruvate, which can also act as a poor substrate. while catalysing the decarboxylation of this alternative substrate, the enzyme undergoes a progressive but partial inactivation over several hours. the extent of inactivation depends upon the ph and upon the concentration of 3-hydroxypyruvate. after partial inactivation and removal of unchanged 3-hydroxypyruvate, enzymic activity recovers slowly. we suggest that inactivation r ...19902310379
analysis and stability of zymomonas mobilis atcc 10988 plasmid pzmo3.plasmid pzmo3 of zymomonas mobilis strain atcc 10988 was found to be nonhomologous either to chromosomal dna or to any other plasmids of the strains atcc 10988, ncib 11163, and cp4. it contained single sites for the restriction endonucleases sphi, bgli, and hindiii, as well as at least four sites for sau3a. its origin of replication is located within the 1.54-kb sau3a fragment as it was found that only the recombinant plasmid pds3154, which contained this fragment, showed vectorial incompatibili ...19902349282
ethanol effect on the membrane protein pattern of zymomonas mobilis. 19852408556
expression of zymomonas mobilis adhb (encoding alcohol dehydrogenase ii) and adhb-lacz operon fusions in recombinant z. mobilis.the zymomonas mobilis alcohol dehydrogenase ii gene (adhb) was overexpressed 7- to 14-fold on a recombinant plasmid, accompanied by a small decrease in growth rate. a fragment containing the truncated gene with promoter reduced expression from the chromosomal gene as measured immunologically and enzymatically, consistent with the presence of a trans-active regulatory factor and positive regulatory control. both the complete gene and the promoter fragment increased pyruvate decarboxylase and gluc ...19892504692
transposable elements for efficient manipulation of a wide range of gram-negative bacteria: promoter probes and vectors for foreign genes.we describe here the construction and use of a series of modified transposons based on the insertion sequence is1. like their parent, omegon-km [fellay et al., gene 76 (1989) 215-226], these elements permit efficient insertional mutagenesis of a variety of gram-negative bacteria. the presence of a functional pbr322 origin of replication within the transposable element facilitates subsequent cloning of the mutated gene. the omegon-km system was previously shown to function in pseudomonas putida, ...19892559879
prokaryotic triterpenoids. a novel hopanoid from the ethanol-producing bacterium zymomonas mobilis.among the triterpenoids of the bacterium zymomonas mobilis a novel hopanoid, 32-oxobacteriohopane-33,34,35-triol beta-linked via its primary hydroxy group to glucosamine, has been isolated as a minor compound.19892640564
pyruvate decarboxylase is like acetolactate synthase (ilv2) and not like the pyruvate dehydrogenase e1 subunit.protein sequences of pyruvate decarboxylase (pdc) derived from cloned yeast (saccharomyces cerevisiae) and bacterial (zymomonas mobilis) genes were compared with each other and with sequence databases. extensive sequence similarities were found between them and with two others: cytochrome-linked pyruvate oxidase from escherichia coli and acetolactate synthase (ilvi in e. coli; ilv2 gene in s. cerevisiae). all catalyse decarboxylation of pyruvate using thiamine pyrophosphate (tpp) as cofactor. ge ...19892651151
similarity of escherichia coli propanediol oxidoreductase (fuco product) and an unusual alcohol dehydrogenase from zymomonas mobilis and saccharomyces cerevisiae.the gene that encodes 1,2-propanediol oxidoreductase (fuco) from escherichia coli was sequenced. the reading frame specified a protein of 383 amino acids (including the n-terminal methionine), with an aggregate molecular weight of 40,642. the induction of fuco transcription, which occurred in the presence of fucose, was confirmed by northern blot analysis. in e. coli, the primary fuco transcript was approximately 2.1 kilobases in length. the 5' end of the transcript began more than 0.7 kilobase ...19892661535
molecular analysis and nucleotide sequence of the adh1 gene encoding an nadph-dependent butanol dehydrogenase in the gram-positive anaerobe clostridium acetobutylicum.the nucleotide sequence of a 2081-bp fragment of clostridium acetobutylicum dna containing the adh1 gene was determined. the butanol dehydrogenase gene is referred to as the adh1 gene since it was shown to have activity using butanol and ethanol as substrates. the adh1 gene consisted of 1164 bp and encoded an alcohol dehydrogenase (adh) enzyme of 388 aa residues with an mr of 43,274. the adh1 gene was separated from an upstream open reading frame by an intergenic region of 354 bp. no promoter co ...19892673928
efficient ethanol production from glucose, lactose, and xylose by recombinant escherichia coli.lactose and all of the major sugars (glucose, xylose, arabinose, galactose, and mannose) present in cellulose and hemicellulose were converted to ethanol by recombinant escherichia coli containing plasmid-borne genes encoding the enzymes for the ethanol pathway from zymomonas mobilis. environmental tolerances, plasmid stability, expression of z. mobilis pyruvate decarboxylase, substrate range, and ethanol production (from glucose, lactose, and xylose) were compared among eight american type cult ...19892675762
differential expression of gap and pgk genes within the gap operon of zymomonas zymomonas mobilis, the genes encoding glyceraldehyde-3-phosphate dehydrogenase (gap) and phosphoglycerate kinase (pgk) are encoded in an operon that is transcribed from tandem promoters. the promoter-proximal gap gene is expressed at six- to ninefold higher levels than the pgk gene from chromosomal genes and from multiple copies of plasmid-borne genes. two dominant transcripts were identified. the smaller, most abundant transcript contained primarily the gap message, whereas the larger, less ...19892687242
[cloning the pyruvate decarboxylase gene of zymomonas mobilis and its expression in escherichia coli].the pyruvate decarboxylase gene of zymomonas mobilis cp4 has been cloned in escherichia coli strain tg1 cells on the puc18 vector plasmid. activity of the enzyme in the lysates of the obtained clones is about 30 units per 1 mg of protein. neither the dependence of the pyruvate decarboxylase activity on the presence of iptg or glucose in the cultivation medium nor the difference in activity of the enzyme for the clones harbouring the recombinant plasmids with the different orientation of the pyru ...19892693955
homology of saccharomyces cerevisiae adh4 to an iron-activated alcohol dehydrogenase from zymomonas mobilis.insertion of the transposable element ty at the adh4 locus results in increased levels of a new alcohol dehydrogenase (adh) activity in saccharomyces cerevisiae. the dna sequence of this locus has been determined. it contains a long open reading frame which is not homologous to the other adh isozymes that have been characterized in s. cerevisiae nor does it show obvious homology to drosophila adh. the hypothetical adh does, however, show strong homology to the sequence of an iron-activated adh f ...19872823079
phosphoglycerate kinase gene from zymomonas mobilis: cloning, sequencing, and localization within the gap operon.the zymomonas mobilis gene encoding phosphoglycerate kinase (ec, pgk, has been cloned into escherichia coli and sequenced. it consists of 336 amino acids, including the n-terminal methionine, with a molecular weight of 41,384. this promoterless gene is located 225 base pairs downstream from the gap gene and is part of the gap operon. previous studies have shown that the specific activities of glyceraldehyde-3-phosphate dehydrogenase and phosphoglycerate kinase do not change coordinately ...19882832389
localization and mapping of co2 fixation genes within two gene clusters in rhodobacter sphaeroides.two fructose 1,6-bisphosphatase structural genes (fbpa and fbpb) have been identified within two unlinked gene clusters that were previously shown to contain the rhodobacter sphaeroides sequences that code for form i and form ii ribulose 1,5-bisphosphate carboxylase-oxygenase and phosphoribulokinase. the fbpa and fbpb genes were localized to a region immediately upstream from the corresponding prka and prkb sequences and were found to be transcribed in the same direction as the phosphoribulokina ...19882834328
cosmid cloning of five zymomonas trp genes by complementation of escherichia coli and pseudomonas putida trp mutants.a library of zymomonas mobilis genomic dna was constructed in the broad-host-range cosmid plafr1. the library was mobilized into a variety of escherichia coli and pseudomonas putida trp mutants by using the helper plasmid prk2013. five z. mobilis trp genes were identified by the ability to complement the trp mutants. the trpf, trpb, and trpa genes were on one cosmid, while the trpd and trpc genes were on two separate cosmids. the organization of the z. mobilis trp genes seems to be similar to th ...19882838460
comparison of the structural genes for pyruvate decarboxylase in different zymomonas mobilis strains.the nucleotide sequence of the pyruvate decarboxylase gene from zymomonas mobilis atcc 29191 was determined and compared with the sequence of the corresponding gene in z. mobilis atcc 31821. differences were found, leading to variations on the amino acid level and to different sites for restriction endonucleases.19882838467
modulation of alcohol dehydrogenase isoenzyme levels in zymomonas mobilis by iron and zinc.zymomonas mobilis is an unusual microorganism which utilizes both iron-containing alcohol dehydrogenase (adhii) and zinc-containing alcohol dehydrogenase (adhi) isoenzymes during fermentative growth. this organism is obligately ethanologenic, and alcohol dehydrogenase activity is essential. the activities of adhi and adhii were altered by supplementing growth medium with iron or zinc salts and by iron starvation. growth under iron-limiting conditions (chelators, minimal medium) reduced adhii act ...19892914864
cloning, sequencing, and characterization of the principal acid phosphatase, the phoc+ product, from zymomonas mobilis.the zymomonas mobilis gene encoding acid phosphatase, phoc, has been cloned and sequenced. the gene spans 792 base pairs and encodes an mr 28,988 polypeptide. this protein was identified as the principal acid phosphatase activity in z. mobilis by using zymograms and was more active with magnesium ions than with zinc ions. its promoter region was similar to the -35 "pho box" region of the escherichia coli pho genes as well as the regulatory sequences for saccharomyces cerevisiae acid phosphatase ...19892914872
the stereospecificity of the ferrous-ion-dependent alcohol dehydrogenase from zymomonas mobilis.alcohol dehydrogenase from zymomonas mobilis has been found to transfer the pro-r hydrogen of nadh to acetaldehyde. this is the first report of the stereospecificity of a dehydrogenase in the mechanistic and structural class of fe2+-dependent alcohol dehydrogenases and offers an opportunity to expand mechanistic hypotheses relating stereospecificity, reaction mechanism and reaction thermodynamics in dehydrogenases.19892924772
the two alcohol dehydrogenases of zymomonas mobilis. purification by differential dye ligand chromatography, molecular characterisation and physiological roles.the two alcohol dehydrogenases found in zymomonas mobilis have each been purified using dye-ligand chromatography and affinity elution with nucleotides. the isoenzyme with lower electrophoretic mobility (zadh-1) is a zinc enzyme with properties essentially similar to preparations described elsewhere. the faster isoenzyme (zadh-2) accounted for some 90% of the ethanol-oxidizing activity in freshly prepared extracts and corresponded to the iron-activated enzyme previously described. this enzyme wa ...19862935393
nmr studies of [1-2h]glucose metabolism in zymomonas complementary experiments the metabolism of [1-2h]glucose in h2o and of unlabelled glucose in 2h2o by zymomonas mobilis was examined. the utilization of [1-2h]glucose by z. mobilis was monitored by high-resolution 2h nmr. the deuterium-labelling pattern and stereochemistry of the ethanols produced from the metabolism of [1-2h]glucose and unlabelled glucose in 2h2o were determined by a combination of 13c and 1h nmr and selective enzyme action. the labelling patterns were explained in terms of ...19862940086
behavior of the incw plasmid sa in zymomonas mobilis.the stability of the broad-host-range incw r plasmid sa in zymomonas mobilis zm6100(sa) was monitored using three antibiotic resistance markers carried by sa. when grown in batch culture without selection, zm6100(sa) rapidly lost the sa plasmid. when grown with selection for either kanamycin or spectinomycin resistance, the three sa markers were retained in at least 90% of the population, with spontaneous loss of chloramphenicol resistance being observed in the rest of the population. when zm610 ...19872962214
gluconate kinase from zymomonas mobilis: isolation and characteristics.the enzyme gluconate kinase ec has been found at high levels in glucose-grown zymomonas mobilis cells. a simple procedure, based on differential dye-ligand chromatography, has been used to isolate the enzyme, purifying it some 600-fold. the purified enzyme is a monomer of molecular weight 18,000 da, which is much smaller than other gluconate kinases reported. it has a relatively low affinity for atp. (km = 1.5 mm), but high for gluconate (km = 0.33 mm), and has little activity with any ...19852990475
simultaneous purification and characterization of glucokinase, fructokinase and glucose-6-phosphate dehydrogenase from zymomonas mobilis.the three enzymes glucokinase (ec, fructokinase (ec and glucose-6-phosphate dehydrogenase (ec were isolated in high yield from extracts of zymomonas mobilis. the principal steps in the isolation procedures involved the use of selected dye-ligand adsorbent columns, with affinity elution of two of the three enzymes. glucokinase and fructokinase are dimeric proteins (2 x 33000 da and 2 x 28000 da respectively) and glucose-6-phosphate dehydrogenase is a tetramer (4 x 5200 ...19852992451
isolation and properties of the glycolytic enzymes from zymomonas mobilis. the five enzymes from glyceraldehyde-3-phosphate dehydrogenase through to pyruvate kinase.the five glycolytic enzymes glyceraldehyde-3-phosphate dehydrogenase, phosphoglycerate kinase, phosphoglycerate mutase, enolase and pyruvate kinase were each purified from extracts of zymomonas mobilis cells, by using dye-ligand chromatography as the principal step. two procedures, producing three and two of the enzymes respectively, are described in detail. z. mobilis glyceraldehyde-phosphate dehydrogenase was found to be similar in most respects to the enzyme from other sources, except for hav ...19863026343
promoter and nucleotide sequences of the zymomonas mobilis pyruvate decarboxylase.dna sequence analysis showed that pyruvate decarboxylase (one of the most abundant proteins in zymomonas mobilis) contains 559 amino acids. the promoter for the gene encoding pyruvate decarboxylase was not recognized by escherichia coli, although the cloned gene was expressed at relatively high levels under the control of alternative promoters. the promoter region did not contain sequences which could be identified as being homologous to the generalized promoter structure for e. coli. hydropathy ...19873029037
nucleotide sequence of the pyruvate decarboxylase gene from zymomonas mobilis.pyruvate decarboxylase (ec, the penultimate enzyme in the alcoholic fermentation pathway of zymomonas mobilis, converts pyruvate to acetaldehyde and carbon dioxide. the complete nucleotide sequence of the structural gene encoding pyruvate decarboxylase from zymomonas mobilis has been determined. the coding region is 1704 nucleotides long and encodes a polypeptide of 567 amino acids with a calculated subunit mass of 60,790 daltons. the amino acid sequence was confirmed by comparison with ...19873029726
construction of a transposon containing a gene for polygalacturonate trans-eliminase from klebsiella oxytoca.a dna fragment containing a klebsiella oxytoca gene for polygalacturonate trans-eliminase was cloned into the kanamycin resistance transposon tn5. this new transposon, designated tn5-pga+, had a transposition frequency of 1 x 10(-6). the broad host range plasmid pr751::tn5-pga+ was conjugally transferred to a variety of genetic backgrounds. the ability to degrade polygalacturonate was expressed in aeromonas hydrophila, alcaligenes eutrophus, azotomonas insolita, escherichia coli, pseudomonas put ...19873034186
gene expression in zymomonas mobilis: promoter structure and identification of membrane anchor sequences forming functional lacz' fusion proteins.we have described a procedure for the isolation of lacz' fusion genes which contain anchor sequences conferring membrane association. this method was used to isolate fragments of dna from zymomonas mobilis which contain promoter activity and amino-terminal sequences. the sequences and transcriptional initiation sites of three of these were compared. both escherichia coli and z. mobilis recognized similar regions of dna for transcriptional initiation. five to eight consecutive hydrophobic amino a ...19873034853
overexpression, purification and properties of alcohol dehydrogenase iv from saccharomyces cerevisiae.we have purified adhiv, a novel alcohol dehydrogenase (adh) isozyme in the yeast saccharomyces cerevisiae, after increasing the normally low amount of adhiv protein in laboratory strains. this was done by overexpression of the structural gene (adh4) on a 2micro-based multicopy vector. characterization of the purified enzyme revealed a dimeric structure as well as a different substrate specificity and ph profile as compared to other alcohol dehydrogenase isozymes. on the other hand, we could demo ...19883282541
expression and stability of a recombinant plasmid in zymomonas mobilis and escherichia coli.a recombinant plasmid was constructed by ligating ecori digests of the plasmid cloning vector pbr325 and pzmo2, one of the natural plasmids of zymomonas mobilis atcc 10988. this vector, named pds212 (total size 7.9 kb), which was able to transform escherichia coli efficiently, was also transferred to z. mobilis hosts by mobilization during conjugation using the helper plasmid prk2013. pds212 was inherited stably in both e. coli and z. mobilis hosts and could be recovered intact from them. marker ...19873309139
genetic engineering of ethanol production in escherichia coli.the genes encoding essential enzymes of the fermentative pathway for ethanol production in zymomonas mobilis, an obligately ethanologenic bacterium, were inserted into escherichia coli under the control of a common promoter. alcohol dehydrogenase ii and pyruvate decarboxylase from z. mobilis were expressed at high levels in e. coli, resulting in increased cell growth and the production of ethanol as the principal fermentation product from glucose. these results demonstrate that it is possible to ...19873322191
the kinetics of glucose-fructose oxidoreductase from zymomonas mobilis.glucose-fructose oxidoreductase operates by a classic ping-pong mechanism with a single site for all substrates: glucose, fructose, gluconolactone and sorbitol. the km values for these substrates were determined. the values of kcat are 200 s-1 and 0.8 s-1 for the forward and reverse directions respectively. the overall catalytic process consists of two half-reactions with alternate reduction of nadp+ and oxidation of nadph tightly bound to the enzyme. reduction of enzyme-nadp+ by glucose and oxi ...19883356190
pyruvate decarboxylase of zymomonas mobilis: isolation, properties, and genetic expression in escherichia coli.pyruvate decarboxylase (ec from zymomonas mobilis purified to homogeneity by using dye-ligand and ion-exchange chromatography. antibodies produced against the enzyme and the amino-terminal sequence obtained for the pure enzyme were used to select and confirm the identity of a genomic clone encoding the enzyme selected from a genomic library of z. mobilis dna cloned into puc9. the genomic fragment encoding the enzyme expressed high levels of pyruvate decarboxylase in escherichia coli. po ...19873546263
cloning and sequencing of the alcohol dehydrogenase ii gene from zymomonas mobilis.the gene which encodes alcohol dehydrogenase ii (adhb) from zymomonas mobilis was cloned in escherichia coli as a 1.4-kilobase dna fragment by using a novel indicator plate which directly detects the expression of this activity by recombinant colonies. the dna sequence for this clone contained an open reading frame encoding a polypeptide of 383 amino acids, with a molecular weight of 40,141. although this protein exhibited very little homology with other known alcohol dehydrogenases, the predict ...19873584063
glycolytic flux in zymomonas mobilis: enzyme and metabolite levels during batch fermentation.the rate at which z. mobilis (entner-doudoroff pathway) converts high concentrations of glucose (20%) into ethanol plus co2 changes as ethanol accumulates in the surrounding broth. this decline in glycolytic activity (per milligram of cell protein) does not result from inhibitory effects of ethanol, which can be reversed immediately by ethanol removal. the peak of fermentative activity (58 mumol of co2 evolved per mg of cell protein per h) occurred after the accumulation of 1.1% ethanol (18 h) a ...19873611027
glyceraldehyde-3-phosphate dehydrogenase gene from zymomonas mobilis: cloning, sequencing, and identification of promoter region.the gene encoding glyceraldehyde-3-phosphate dehydrogenase was isolated from a library of zymomonas mobilis dna fragments by complementing a deficient strain of escherichia coli. it contained tandem promoters which were recognized by e. coli but appeared to function less efficiently than the enteric lac promoter in e. coli. the open reading frame for this gene encoded 337 amino acids with an aggregate molecular weight of 36,099 (including the n-terminal methionine). the primary amino acid sequen ...19873680173
glucose-fructose oxidoreductase, a new enzyme isolated from zymomonas mobilis that is responsible for sorbitol production.the enzymes responsible for sorbitol formation in zymomonas mobilis were investigated. a previously undescribed enzyme catalyzes the intermolecular oxidation-reduction of glucose and fructose to form gluconolactone and sorbitol. this enzyme has been purified; it had a subunit size of 40,000 daltons and is probably tetrameric at low ph. it contained tightly bound nadp as the hydrogen carrier and did not require any added cofactor for activity. in addition, a gluconolactonase has been isolated, al ...19863745122
effect of ethanol and heat stresses on the protein pattern of zymomonas mobilis.heat or ethanol shock of zymomonas mobilis enhanced the labeling by [35s]methionine of several polypeptides and induced the synthesis of a new polypeptide (molecular weight, 18,500) associated with the envelope fraction. these results indicate the existence of a typical heat-shock response in z. mobilis. this response could be involved in the induction of increased ethanol tolerance in z. mobilis cells.19863949711
mechanism of ethanol inhibition of fermentation in zymomonas mobilis cp4.accumulation of alcohol during fermentation is accompanied by a progressive decrease in the rate of sugar conversion to ethanol. in this study, we provided evidence that inhibition of fermentation by ethanol can be attributed to an indirect effect of ethanol on the enzymes of glycolysis involving the plasma membrane. ethanol decreased the effectiveness of the plasma membrane as a semipermeable barrier, allowing leakage of essential cofactors and coenzymes. this leakage of cofactors and coenzymes ...19854044518
glucose and fructose metabolism in zymomonas anaerobia.isotopic and enzymic evidence indicates that zymomonas anaerobia ferments glucose via the entner-doudoroff pathway. the molar growth yields with glucose (5.89) and fructose (5.0) are lower than those for the related organism zymomonas mobilis and the observed linear growth suggests that energetically uncoupled growth occurs. a survey of enzymes of carbohydrate metabolism revealed the presence of weak phosphofructokinase and fructose 1,6-diphosphate aldolase activities but phosphoketolase, transk ...19714259336
the route of ethanol formation in zymomonas mobilis.1. enzymic evidence supporting the operation of the entner-doudoroff pathway in the anaerobic conversion of glucose into ethanol and carbon dioxide by zymomonas mobilis is presented. 2. cell extracts catalysed the formation of equimolar amounts of pyruvate and glyceraldehyde 3-phosphate from 6-phosphogluconate. evidence that 3-deoxy-2-oxo-6-phosphogluconate is an intermediate in this conversion was obtained. 3. cell extracts of the organism contained the following enzymes: glucose 6-phosphate de ...19664287842
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