Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:5.4.2.8 (phosphomannomutase)
 238 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Subcloning, transposon insertion, and deletion analysis revealed that the Escherichia coli O9 rfb region is about 12 kb in size. The region encodes at least seven polypeptides of 89, 74, 55, 50, 44, 41 and 39.5 kDa. Southern hybridization analysis of rfb regions of E. coli O8 and O9, and Klebsiella O3 and O5 serotypes (all of these O polysaccharides are mannose homopolymers and the structures of the repeating unit of E. coli O9 and Klebsiella O3 are identical) showed that a central region specific for E. coli O9 and Klebsiella O3 is flanked by two regions common to all four. Complementation experiments using strains with known defects and specific tests for the enzymic activity showed that the 50 and 55 kDa polypeptides, encoded by the common region, are phosphomannomutase (PMM) and GDP-mannose pyrophosphorylase (GMP), respectively. Nucleotide sequencing of the region revealed the presence of two genes, rfbK and rfbM, analogous to the corresponding genes of Salmonella typhimurium. In E. coli O9, rfbK and rfbM encode proteins of 460 amino acids (50,809 Da) and 471 amino acids (52,789 Da). The amino acid sequence of GMP was conserved in RfbMs of E. coli O7 and Salmonella groups B, C1 and C2, CpsB of S. typhimurium, AlgA of Pseudomonas aeruginosa, and XanB of Xanthomonas campestris. The phylogenetic trees of PMM and GMP were different in topology and in the evolutionary distances from ancestors.
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PMID:Genetic analysis of Escherichia coli O9 rfb: identification and DNA sequence of phosphomannomutase and GDP-mannose pyrophosphorylase genes. 816 91

A region of pSG30 that complements the pyocin-derived gonococcal lipooligosaccharide (LOS) mutants 1291d and 1291e was characterized by DNA sequence analysis and an open reading frame of 1,380 bases was identified that is 89% similar and 56% identical over 452 amino acids to the algC gene product from Pseudomonas aeruginosa that encodes phosphomannomutase. Enzymatic analysis of gonococcal crude protein extracts demonstrated that pSG30 encodes phosphoglucomutase (PGM) and phosphomannomutase activity. This activity is absent in 1291d and 1291e but is restored upon introduction of pSG30. PGM encoded by pSG34, a subclone of pSG30, was able to complement Escherichia coli PGM1, a strain deficient in PGM, as determined by bacteriophage C21 plaque formation. A revertant of 1291d that binds monoclonal antibody 2-1-L8 (specific for a 3.6-kDa LOS component) was isolated. The construction of a site-specific deletion of this region in the chromosome of 1291 confirms the role of this open reading frame in LOS biosynthesis.
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PMID:Role of phosphoglucomutase in lipooligosaccharide biosynthesis in Neisseria gonorrhoeae. 818 95

Alginate production by the highly alginate-producing Pseudomonas aeruginosa 8821M was maximal at a dissolved oxygen tension (DOT) of 5% of air saturation. Lower DOT limited growth and alginate synthesis. At higher DOT values up to 70% of air saturation, the specific alginate production rate decreased. Nevertheless, the molecular mass of the alginate increased at higher aerations, as indicated by the viscosity of solutions of the isolated biopolymer. The specific activity of the four enzymes leading to GDP-mannuronic acid formation, phosphomannose isomerase (PMI), phosphomannomutase (PMM), GDP-mannose pyrophosphorylase (GMP) and GDP-mannose dehydrogenase (GMD), increased with DOT of up to 25%. At higher DOT, however, only GMP and GMD maintained their maximum values. Changes observed at high oxygen concentrations in the relative activities of PMI and GMP, which are activities of the same bifunctional protein, were attributed to the much higher sensitivity of PMI activity to irreversible oxidative inactivation. The less pronounced decrease of PMM activity at high DOT correlated with an intermediate sensitivity to oxidative inactivation, but could also be related to sequential induction of PMM by the product of the PMI reaction. Thus, oxygen-dependence of alginate synthesis was at least partially the effect of DOT on GDP-mannuronic acid formation. Optimal aerations for maximal alginate production (DOT = 5-10%) were below the aeration level (70%) that led to the highest viscosity. These results suggest that, like GMD, polymerization activity is not very sensitive to oxidative inactivation and they are consistent with the hypothesis that polymerization is dependent on GMD activity, or is regulated in a similar way.
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PMID:Oxygen-dependent alginate synthesis and enzymes in Pseudomonas aeruginosa. 838 19

We have cloned a lipopolysaccharide (LPS) biosynthetic gene from Pseudomonas aeruginosa PAO1 that complements the defect in the production and incorporation of LPS O side chains in the LPS-rough strain AK1012. This gene was characterized by pulsed-field gel electrophoresis, deletion and restriction mapping of the cloned DNA, and biochemical analysis of the protein product. The cloned DNA was found to map to the 7-to-11-min region of the P. aeruginosa chromosome, and the gene needed for complementation of the LPS-rough phenotype was contained on a 2.6-kb HindIII-SacI fragment. This same size restriction fragment contains the alginate gene algC, which encodes the enzyme phosphomannomutase (PMM) and also maps to this region of the P. aeruginosa chromosome. The LPS-rough strain AK1012 was deficient in PMM activity, and this activity was restored to parental levels when the cloned gene was transferred to strain AK1012. In addition, the cloned gene could complement the PMM deficiency in the algC mutant strain 8858, and the cloned algC gene could restore the LPS-smooth phenotype to strain AK1012. These results indicate that the gene we have cloned is equivalent to the alginate gene algC. We designate this gene pmm to emphasize that it encodes the enzyme PMM, which has been shown to be essential for alginate production, and we demonstrate that PMM activity is required for the LPS-smooth phenotype in P. aeruginosa PAO1.
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PMID:Synthesis of lipopolysaccharide O side chains by Pseudomonas aeruginosa PAO1 requires the enzyme phosphomannomutase. 844 70

The pmmA gene encoding a bifunctional phosphomannomutase/phosphoglucomutase (PMM/PGM) from the photosynthetic prokaryote, Prochlorothrix hollandica has been cloned and sequenced. The gene encodes a 51827 Da polypeptide 48% identical to the PMM of Azospirillum brasilense, 37% identical to the PGMs of pathogenic Neisseria sp. and 37% identical to the bifunctional AlgC PGM/PMM of Pseudomonas aeruginosa. The pmmA gene encodes an enzyme having both PGM and PMM activities as judged by both enzyme assays and complementation analysis in which the cloned gene partially corrected the pgm-1 mutation of Escherichia coli.
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PMID:Cloning and functional analysis of the pmmA gene encoding phosphomannomutase from the photosynthetic prokaryote Prochlorothrix hollandica. 876 22

Pseudomonas aeruginosa M60, a mucoid strain, was grown in continuous culture (D 0.05 h-1) under ammonia limitation with glucose as the carbon source. Steady-state alginate production occurred for only 1-2 d under these conditions [qalginate 0.097 g alginate h-1 (g dry wt cells)-1], after which time the percentage of mucoid cells and the alginate concentration in the culture decreased in parallel and approached zero after approximately 10 d. These changes were accompanied by similar decreases in the activities of the alginate biosynthetic enzymes (represented by phosphomannomutase and GDP-mannose dehydrogenase) and by a large increase in the activity of the first enzyme of the 'external' non-phosphorylative pathway of glucose metabolism, glucose dehydrogenase. In contrast, the activities of other enzymes associated with this pathway (gluconate dehydrogenase, 2-ketogluconate kinase plus 2-ketogluconate-6-phosphate reductase) or with the 'internal' phosphorylative pathway of glucose metabolism (glucokinase and glucose-6-phosphate dehydrogenase) remained essentially unchanged. The loss of mucoidy and alginate production was accompanied by the appearance of low concentrations of intracellular polyhydroxyalkanoate (PHA) and of extracellular gluconate and 2-ketogluconate (partly at the expense of alginate production and partly as a result of increased glucose consumption). It is suggested that ammonia-limited, glucose-excess cultures of P. aeruginosa growing at low dilution rate are unable fully to regulate the rate at which glucose and/or its 'external' pathway metabolites are taken up by the cell, and therefore form copious amounts of alginate in order both to overcome the potentially deleterious osmotic effects of accumulating surplus intracellular metabolites and to consume the surplus ATP generated by the further oxidation of these metabolites. The loss of mucoidy invokes the use of an alternative, but analogous, strategy via which non-mucoid cells produce an osmotically inactive intracellular product (PHA) plus increased amounts of the extracellular metabolites gluconate and 2-ketogluconate via the low-energy-yielding and, under these conditions, largely dead-end 'external' metabolic pathway.
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PMID:Physiological and biochemical changes accompanying the loss of mucoidy by Pseudomonas aeruginosa. 893 14

The plasmid vectors described in this report are derived from the broad-host-range RK2 replicon and can be maintained in many gram-negative bacterial species. The complete nucleotide sequences of all of the cloning and expression vectors are known. Important characteristics of the cloning vectors are as follows: a size range of 4.8 to 7.1 kb, unique cloning sites, different antibiotic resistance markers for selection of plasmid-containing cells, oriT-mediated conjugative plasmid transfer, plasmid stabilization functions, and a means for a simple method for modification of plasmid copy number. Expression vectors were constructed by insertion of the inducible Pu or Pm promoter together with its regulatory gene xylR or xylS, respectively, from the TOL plasmid of Pseudomonas putida. One of these vectors was used in an analysis of the correlation between phosphoglucomutase activity and amylose accumulation in Escherichia coli. The experiments showed that amylose synthesis was only marginally affected by the level of basal expression from the Pm promoter of the Acetobacter xylinum phosphoglucomutase gene (celB). In contrast, amylose accumulation was strongly reduced when transcription from Pm was induced. CelB was also expressed with a very high induction ratio in Xanthomonas campestris. These experiments showed that the A. xylinum celB gene could not complement the role of the bifunctional X. campestris phosphoglucomutase-phosphomannomutase gene in xanthan biosynthesis. We believe that the vectors described here are useful for cloning experiments, gene expression, and physiological studies with a wide range of bacteria and presumably also for analysis of gene transfer in the environment.
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PMID:Construction and use of a versatile set of broad-host-range cloning and expression vectors based on the RK2 replicon. 902 17

The mRNA levels of algA, algC and algD genes increased, coordinately, in cells of the highly mucoid Pseudomonas aeruginosa 8821M grown under increasing dissolved oxygen tensions (DOT) of up to 70% of air saturation. These genes encode the bifunctional protein with phosphomannose isomerase (PMI) and GDP-mannose pyrophosphorylase (GMP) activities (algA), the phosphomannomutase (PMM) (algC) and the GDP-mannose dehydrogenase (GMD) (algD). These four enzyme activities are necessary for the synthesis of GDP-mannuronic acid, which is the activated sugar precursor for alginate polymerization. For growth-limiting DOT--lower than 10% of air saturation--the increase in mRNA levels of algA, algC and algD with oxygen concentration was accompanied by a strong increase in the activity of the encoded enzymes and the consequent increase in alginate synthesis. However, and despite the upregulation of alginate gene transcription by DOT above 10% of air saturation, the activities of the encoded enzymes either maintained (GMP and GMD) or decreased (PMI and PMM) their levels at high oxygen tensions, leading to a slight decrease in alginate synthesis. This has previously been attributed to the oxidative inactivation of alginate enzymes, particularly of PMM and PMI activities.
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PMID:Oxygen-dependent upregulation of transcription of alginate genes algA, algC and algD in Pseudomonas aeruginosa. 940 3

Pseudomonas aeruginosa is capable of producing various cell-surface polysaccharides including alginate, A-band and B-band lipopolysaccharides (LPS). The D-mannuronic acid residues of alginate and the D-rhamnose (D-Rha) residues of A-band polysaccharide are both derived from the common sugar nucleotide precursor GDP-D-mannose (D-Man). Three genes, rmd, gmd and wbpW, which encode proteins involved in the synthesis of GDP-D-Rha, have been localized to the 5' end of the A-band gene cluster. In this study, WbpW was found to be homologous to phosphomannose isomerases (PMIs) and GDP-mannose pyrophosphorylases (GMPs) involved in GDP-D-Man biosynthesis. To confirm the enzymatic activity of WbpW, Escherichia coli PMI and GMP mutants deficient in the K30 capsule were complemented with wbpW, and restoration of K30 capsule production was observed. This indicates that WbpW, like AlgA, is a bifunctional enzyme that possesses both PMI and GMP activities for the synthesis of GDP-D-Man. No gene encoding a phosphomannose mutase (PMM) enzyme could be identified within the A-band gene cluster. This suggests that the PMM activity of AlgC may be essential for synthesis of the precursor pool of GDP-D-Man, which is converted to GDP-D-Rha for A-band synthesis. Gmd, a previously reported A-band enzyme, and Rmd are predicted to perform the two-step conversion of GDP-D-Man to GDP-D-Rha. Chromosomal mutants were generated in both rmd and wbpW. The Rmd mutants do not produce A-band LPS, while the WbpW mutants synthesize very low amounts of A band after 18 h of growth. The latter observation was thought to result from the presence of the functional homologue AlgA, which may compensate for the WbpW deficiency in these mutants. Thus, WbpW AlgA double mutants were constructed. These mutants also produced low levels of A-band LPS. A search of the PAO1 genome sequence identified a second AlgA homologue, designated ORF488, which may be responsible for the synthesis of GDP-D-Man in the absence of WbpW and AlgA. Polymerase chain reaction (PCR) amplification and sequence analysis of this region reveals three open reading frames (ORFs), orf477, orf488 and orf303, arranged as an operon. ORF477 is homologous to initiating enzymes that transfer glucose 1-phosphate onto undecaprenol phosphate (Und-P), while ORF303 is homologous to L-rhamnosyltransferases involved in polysaccharide assembly. Chromosomal mapping using pulsed field gel electrophoresis (PFGE) and Southern hybridization places orf477, orf488 and orf303 between 0.3 and 0.9 min on the 75 min map of PAO1, giving it a map location distinct from that of previously described polysaccharide genes. This region may represent a unique locus within P. aeruginosa responsible for the synthesis of another polysaccharide molecule.
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PMID:Synthesis of the A-band polysaccharide sugar D-rhamnose requires Rmd and WbpW: identification of multiple AlgA homologues, WbpW and ORF488, in Pseudomonas aeruginosa. 978 79

The low activity levels of the four GDP-D-mannuronic acid-forming enzymes, even in highly alginate-producing strains of Pseudomonas aeruginosa, have made it difficult to compare enzyme activities accompanying the loss/acquisition of mucoidy. Using optimized conditions, we compared the specific activity of these enzymes in three different mucoid P. aeruginosa cystic fibrosis isolates, in their nonmucoid spontaneous variants, and in mucoid variants that emerged during extended incubation of these nonmucoid forms in acetamide broth. A correlation was established between the promptness of emergence of the mucoid forms and the differing sensitivity to nutrient-limitation-induced death of the nonmucoid compared with the isogenic mucoid population. Consistent with the undetectable levels of algD mRNA in nonmucoid forms and with the concept that the step catalyzed by the algD-encoded GDP-mannose dehydrogenase (GMD) is a key step in control of the alginate pathway, GMD activity was undetectable or showed negligible values in nonmucoid variants and correlated with alginate production. However, phosphomannose isomerase (PMI), phosphomannomutase (PMM), and GDP-mannose pyrophosphorylase (GMP) activities in the nonmucoid forms were only slightly (40-70%) below the values in the mucoid forms. Nevertheless, no transcripts homologous to algA (encoding a bifunctional enzyme that possesses both PMI and GMP activities) were detected in the nonmucoid form, and the levels of algC (encoding PMM) transcripts, although detectable in the nonmucoid variants, were, in general, much higher in the mucoid forms. These apparently intriguing observations were cleared up by the identification of two algA functional homologues in P. aeruginosa, recently reported by others, and by the identification of one algC homologue, in contig225 of the PAO1 genome sequence, defining a polypeptide with a deduced amino acid sequence that showed significant homology with that of enzymes of the phosphohexomutase family found in databases. Results are also consistent with the requirement of PMI, GMP and PMM activities for the supply of GDP-D-mannose to (at least) A-band lipopolysaccharide synthesis, while GMD channels this precursor into the alginate pathway.
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PMID:Pattern of changes in the activity of enzymes of GDP-D-mannuronic acid synthesis and in the level of transcription of algA, algC and algD genes accompanying the loss and emergence of mucoidy in Pseudomonas aeruginosa. 1020 66


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