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)

The rfb (O antigen) gene cluster of a group C1 Salmonella enterica strain was sequenced; it comprised seven open reading frames which precisely replaced the 16 open reading frames of a group B strain. Two genes of the mannose biosynthetic pathway were present: rfbK (phosphomannomutase) had a G+C content of 0.61 and had only 40% identity to rfbK of group B but was very similar to cpsG of the capsular polysaccharide pathway with 96% identity, whereas rfbM [guanosine diphosphomannose (GDP-Man) pyrophosphorylase] had a G+C content of 0.39. Other genes had G+C contents ranging from 0.24 to 0.28. rfbM(C1) and rfbM(B) had 60% identity, which is much less than expected within a species, but nonetheless indicates a much more recent common ancestor than for rfbK. The other genes showed much lower or no similarity to rfb genes of other S. enterica strains. It appears that the gene cluster evolved outside of Salmonella in a species with low G+C content: the rfbM gene presumably derives from that period whereas the rfbK gene appears to have arisen after transfer of the cluster to S. enterica by duplication of the S. enterica cpsG gene, presumably replacing an rfbK gene of low G+C content.
J Gen Microbiol 1992 Sep
PMID:Sequence and structural analysis of the rfb (O antigen) gene cluster from a group C1 Salmonella enterica strain. 138 93

We report the presence in Salmonella enterica strain LT2 (serovar thyphimurium) of duplicate genes for two steps in the synthesis of GDP-mannose. The previously known genes, rfbK (phosphomannomutase) and rfbM (mannose-1-phosphate guanyltransferase), are part of the gene cluster for the O antigen. The two new genes, cpsB and cpsG, respectively, are thought to be part of the gene cluster for the M antigen capsular polysaccharide, present in many Enterobacteriaceae. The two genes have been sequenced and have a GC content of 0.61, suggesting an origin outside of Salmonella. Comparison of the inferred protein sequences for cpsB and rfbM shows 57% identity of amino acids whereas for cpsG and rfbK there is only 19% identity. It is suggested that the greater divergence between cpsG and rfbK may be due to a period of accelerated evolution, perhaps precipitated by transfer of the genes from another species.
Mol Gen Genet 1991 Jun
PMID:The cps gene cluster of Salmonella strain LT2 includes a second mannose pathway: sequence of two genes and relationship to genes in the rfb gene cluster. 171 67

Pseudomonas aeruginosa region II alginate genes are involved in the biosynthesis of the uronic acid containing exopolysaccharide, alginic acid. We have subcloned and overexpressed various DNA fragments contained within region II in an attempt to further characterize and more precisely localize the genes involved in alginate production. Overexpression of the genes controlling alginate biosynthesis within region II was accomplished by placing various cloned restriction fragments under the transcriptional control of the hybrid trp-lac (tac) promoter, and plasmid encoded proteins were examined in a maxicell expression system. We correlated various region II plasmid constructions with the ability to complement specific alginate negative (alg) mutants and code for polypeptides. Several proteins suspected of being involved in alginate production were encoded by sequences within region II. The results of this study further reveal that the transcriptional orientation of the alg loci within region II appears to be in the direction from argF to pmi. The specific activities of phosphomannomutase (PMM) and GDP-mannose pyrophosphorylase (GMP), two enzymes involved in the formation of the alginate precursor GDP-mannuronic acid, were measured in region II alg mutants and in cells overexpressing cloned segments from region II. Based on these enzyme measurements, we conclude that the remaining region II alg genes do not encode either PMM or GMP. These results support the suggestion that the remaining alg genes in region II are likely to be involved in post GDP-mannuronic acid processing events such as mannuronic acid transport, polymerization, secretion, epimerization and acetylation.
J Gen Microbiol 1987 Aug
PMID:Characterization of the Pseudomonas aeruginosa alginate (alg) gene region II. 312 42

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.
J Gen Microbiol 1993 Mar
PMID:Oxygen-dependent alginate synthesis and enzymes in Pseudomonas aeruginosa. 838 19

A genetic and biochemical analysis of Xanthomonas campestris chromosomal functions required for xanthan polysaccharide synthesis (xps) was undertaken. Seven xps DNA regions were isolated after conjugation of chemically induced non-mucoid mutants with a genomic library of X. campestris DNA. No overlapping segments between regions were detected, based on physical mapping, indicating the unlinked character of these regions. Clones complementing several different mutants belonging to the same region contained overlapping segments of X. campestris chromosomal DNA. Complementation and biochemical analysis, and DNA mapping were used to identify and characterize xpsZZZ, ZV and VZ DNA regions. Mutants in these three regions were able to synthesize both lipid intermediates and xanthan gum in vitro when sugar nucleotides were provided as substrates. HPLC analysis of the intracellular sugar nucleotide content showed that the XpsIII group comprises two different classes of mutants : XpsIIIA, defective in UDP-glucose, UDP-glucuronic acid and GDP-mannose, and XpsIIIB,defective in GDP-mannose. XpsIV mutants were defective in UDP-glucose and UDP-glucuronic acid, and XpsVI mutants were defective only in UDP-glucuronic acid. Analysis of enzyme activities involved in the synthesis of UDP-glucose, GDP-mannose and UDP-glucuronic acid indicated that the xpsZZZA region affects the activity of the phosphoglucomutase/phosphomannomutase enzyme, and the xpsZZZB region affects the mannoisomerase/phosphomannoisomerase activities. The xpsZV mutations affect the activity of the UDPG-pyrophosphorylase enzyme, and the xps VZ mutations affect the activity of the UDPG-dehydrogenase enzyme.
J Gen Microbiol 1993 Mar
PMID:Identification, genetic and biochemical analysis of genes involved in synthesis of sugar nucleotide precursors of xanthan gum. 2005 Apr 14

Sulfobacillus sp. TPY is a moderately thermophilic and acidophilic bacterium found in hydrothermal vents in the Pacific Ocean. This bacterium can oxidize ferrous sulfate (Fe(2+)) and elemental sulfur (S(0)) under separate conditions. We used random arbitrarily primed polymerase chain reaction (RAP-PCR) to screen and identify differentially expressed genes from bacteria grown on Fe(2+) or S(0) as the energy source. Fifty-five differential cDNA fragments were isolated and subjected to single-pass sequencing. Thirty-five fragments were identified as orthologs of known genes in the GenBank databases, of which 19 were confirmed to be differentially expressed at the transcriptional level by Northern blot analysis. Among these 19 genes, 14 genes, including isocitrate dehydrogenase, formyltetrahydrofolate deformylase, 3-hydroxybutyryl-CoA dehydrogenase, and GTP-binding protein, were upregulated in TPY grown on Fe(2+) or downregulated in TPY grown on S(0), while five genes such as the outer membrane adhesion-like protein, phosphomannomutase, and cysteine desulfurase sufS were upregulated in TPY strain grown on S(0) or downregulated in TPY grown on Fe(2+). These altered genes are involved in metabolism, osmotic stress, cell membrane alterations, oxidative stress, and the regulatory adaptive response. These results will aid our understanding of the molecular basis of Fe(2+) or S(0) oxidation by the moderately thermophilic and acidophilic bacteria.
J Gen Appl Microbiol 2010 Oct
PMID:Identification of differentially expressed genes in Sulfobacillus sp. TPY grown on either elemental sulphur or Fe(2+). 2109 35