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PubMed1979

Nonelectrophoretic genetic variability in mosquitoes: polymorphism for temperature-resistant and temperature-sensitive phosphoglucomutase alleles in Culex pipiens.

Homogenates of single individuals of two natural populations and five laboratory populations of Culex pipiens were examined by combining electrophoresis and heat denaturation studies on phosphoglucomutase (PGM). All populations showed a high degree of polymorphism for isoelectrophoretic temperature-resistant (tr) and temperature-sensitive (ts) alleles. Formal genetic data on the heat stability differences of the PGM are given. If both electrophoretic and isoelectrophoretic alleles are taken into account, the mean increase in the degree of heterozygosity is quite remarkable, i.e., about 65%.--The data are considered in relation to the biological significance that this new type of variability of structural genes could have in natural populations.

Alleles↗

PubMed2005

Cloning and characterization of the phosphoglucomutase of Trypanosoma cruzi and functional complementation of a Saccharomyces cerevisiae PGM null mutant.

Trypanosoma cruzi is the etiological agent of Chagas' disease, a chronic illness characterized by progressive cardiomyopathy and/or denervation of the digestive tract. The parasite surface is covered with glycoconjugates, such as mucin-type glycoproteins and glycoinositolphospholipids (GIPLs), whose glycans are rich in galactopyranose (Galp) and/or galactofuranose (Galf) residues. These molecules have been implicated in attachment of the parasite to and invasion of mammalian cells and in modulation of the host immune responses during infection. In T. cruzi, galactose (Gal) biosynthesis depends on the conversion of uridine diphosphate (UDP)-glucose (UDP-Glc) into UDP-Gal by an NAD-dependent reduction catalyzed by UDP-Gal 4-epimerase. Phosphoglucomutase (PGM) is a key enzyme in this metabolic pathway catalyzing the interconversion of Glc-6-phosphate (Glc-6-P) and Glc-1-P which is then converted into UDP-Glc. We here report the cloning of T. cruzi PGM, encoding T. cruzi PGM, and the heterologous expression of a functional enzyme in Saccharomyces cerevisiae. T. cruzi PGM is a single copy gene encoding a predicted protein sharing 61% amino acid identity with Leishmania major PGM and 43% with the yeast enzyme. The 59-trans-splicing site of PGM RNA was mapped to a region located at 18 base pairs upstream of the start codon. Expression of T. cruzi PGM in a S. cerevisiae null mutant-lacking genes encoding both isoforms of PGM (pgm1Delta/pgm2Delta) rescued the lethal phenotype induced upon cell growth on Gal as sole carbon source.

Alternative Splicing↗

PubMed1999

Mapping recombination hotspots in human phosphoglucomutase (PGM1).

Human phosphoglucomutase (PGM1) is a highly poly-morphic protein. Three mutations and four intragenic recombination events between the three mutation sites generate eight protein variants including the four universally common alleles, 1+, 1 -, 2+ and 2 -, and four others that are polymorphic in some Oriental populations, 3+, 3-, 7+ and 7-. The mutations 3/7, 2/1 and +/-are in exons 1A, 4 and 8, and are 40 and 18 kb apart, respectively. Using 12 polymorphic markers, including 2/1 and +/-, we have now obtained direct evidence for a high rate of intragenic recombination across this 58 kb region. From segregation analysis of PGM1 haplotypes in CEPH families, the recombination frequency was estimated to be 1.7%. We have also used a population genetics approach to map the patterns of linkage disequilibrium across the PGM1 gene in three diverse population samples (Caucasian, Chinese and Vietnamese). This has allowed us to compare indirect estimates of intragenic recombination with the meiotic data from family studies. Comprehensive pairwise allelic association analysis of the markers indicated the presence of two recombi-nation 'hotspots': one between exons 1A and 4 and the other in the region of exon 7. These locations are in keeping with the meiotic data and with the original hypothesis of intragenic recombination based on PGM1 isozyme analysis.

Alleles↗

PubMed2003

Molecular and biochemical characterization of cytosolic phosphoglucomutase in wheat endosperm (Triticum aestivum L. cv. Axona).

Evidence from a number of plant tissues suggests that phosphoglucomutase (PGM) is present in both the cytosol and the plastid. The cytosolic and plastidic isoforms of PGM have been partially purified from wheat endosperm (Triticum aestivum L. cv. Axona). Both isoforms required glucose 1,6-bisphosphate for their activity with K(a) values of 4.5 micro M and 3.8 micro M for cytosolic and plastidic isoforms, respectively, and followed normal Michaelis-Menten kinetics with glucose 1-phosphate as the substrate with K(m) values of 0.1 mM and 0.12 mM for the cytosolic and plastidic isoforms, respectively. A cDNA clone was isolated from wheat endosperm that encodes the cytosolic isoform of PGM. The deduced amino acid sequence shows significant homology to PGMs from eukaryotic and prokaryotic sources. PGM activity was measured in whole cell extracts and in amyloplasts isolated during the development of wheat endosperm. Results indicate an approximate 80% reduction in measurable activity of plastidial and cytosolic PGM between 8 d and 30 d post-anthesis. Northern analysis showed a reduction in cytosolic PGM mRNA accumulation during the same period of development. The implications of the changes in PGM activity during the synthesis of starch in developing endosperm are discussed.

Amino Acid Sequence↗

PubMed1995

Identification of membrane-bound phosphoglucomutase and glucose-6 phosphatase by 32P-labeling of rat liver microsomal membrane proteins with 32P-glucose-6 phosphate.

Three recent reports have suggested that rat liver microsomal glucose-6 phosphatase (Glc6Pase) should be a 62-64 kDa polypeptide. In this work, we examine the possibility that the 62-64 kDa could represent a functional dimeric form of the 36.5 kDa glucose-6 phosphate (Glc6P)-phosphohydrolase, previously identified [Countaway et al. (1988) J. Biol. Chem. 263, 2672-2678]. From 32P-labeling experiments with 32P-Glc6P and analysis of 32P-labeled protein by SDS-PAGE and autoradiography, we show that three different rat liver microsomal polypeptides, the apparent molecular masses of which are 62, 54, and 37 kDa, may be specifically labeled with 32P-Glc6P. We demonstrate that the 62 kDa polypeptide is a microsome-bound form of cytosolic phosphoglucomutase, by combining labeling competition experiments and enzymatic assay. It should likely not account for a putative dimeric form of Glc6P-phosphohydrolase. The 37 kDa polypeptide fulfills the criteria of Glc6P-phosphohydrolase. We have not obtained any definitive evidence for its assembly as a dimer under functioning conditions. The 32P-Glc6P-labeling characteristics of the 54 kDa polypeptide are those expected for a protein displaying affinity in the millimolar range of concentration and a high binding capacity for Glc6P. They are consistent with those of a 54 kDa microsomal polypeptide, previously suggested to be involved in Glc6Pase activity.

Animals↗

PubMed1978

Phosphoglucomutase from potato tubers. Chemical and catalytic properties.

The chemical and catalytic properties of potato phosphoglucomutase [EC 2.7.5.1] were studied using various enzyme species (Peaks Ia, Ib, Ic, and II; Takamiya, S. & Fukui, T. (1978) Plant Cell Physiol. 19, 319--328). The molecular weights of the species are all approximately 60,000. No indication of the presence of subunit structure was obtained under various conditions. The amino acid composition of Peak Ia is generally similar to those of the enzymes from other sources, though it has some peculiarities. The Peak Ia and Peak II enzymes both absolutely require alpha-D-glucose 1,6-bisphosphate and Mg2+ for activity, and appear to have a "ping-pong" mechanism. A low concentration of Be2+ inhibits their action, the inhibition being retarded either by Mg2 or EDTA. Although the inhibition patterns by various metabolites, are similar for Peaks Ia and II, they differ in their kinetic parameters and optimal pH values.

Amino Acids↗

PubMedDate not supplied

A phosphoglucomutase polymorphism in the mosquito, Anopheles culicifacies.

A survey of phosphoglucomutase (Pgm) among laboratory strains of Anopheles culicifacies has uncovered two electrophoretic variants. Detailed genetic analysis revealed that these variants are inherited as codominant alleles at a single locus. The Pgm locus has been assigned to linkage group III approximately 39 map units from Acph (acid phosphatase) and 8.5 map units from Dl (dieldrin resistance). The data indicate that the probable gene sequence is Acph-Dl-Pgm.

Acid Phosphatase↗

PubMedDate not supplied

Gene mapping in chicken-Chinese hamster somatic cell hybrids. Serum albumin and phosphoglucomutase-2 structural genes on chicken chromosome 6.

Chicken phosphoglucomutase (PGM-2), serum albumin, vitamin D binding protein (Gc) and phosphoribosyl pyrophosphate amidotransferase (PPAT) structural genes have been mapped to chicken chromosome 6 using chicken-Chinese hamster somatic cell hybrids containing this chromosome as the only chicken genetic material. Chicken PGM-2 activity was detected in the hybrids using cellogel electrophoresis and a substrate, ribose-1-phosphate (R-1-P), that allows the detection of PGM-1 activity in mice and PGM-2 activity in humans. Chicken albumin sequences were detected in the hybrids with the use of a labelled chicken serum albumin cloned cDNA. Classical studies have shown linkage of the serum albumin and Gc genes, and the Gc gene also can be localized to chicken chromosome 6. The PPAT gene was localized to this chromosome in previous studies using these hybrids. A homologous linkage group has been identified in mammals and, therefore, a chromosomal linkage group containing at least four genes--Gc, serum albumin, PPAT, and PGM-2--has been conserved over a period of 300 million years, throughout both avian and mammalian evolution.

Amidophosphoribosyltransferase↗

PubMed2002

Analysis of Mesorhizobium loti glycogen operon: effect of phosphoglucomutase (pgm) and glycogen synthase (g/gA) null mutants on nodulation of Lotus tenuis.

The phosphoglucomutase (pgm) gene codes for a key enzyme required for the formation of UDP-glucose and ADP-glucose, the sugar donors for the biosynthesis of glucose containing polysaccharides. A Mesorhizobium loti pgm null mutant obtained in this study contains an altered form of lipopolysaccharide (LPS), lacks exopolysaccharide (EPS), beta cyclic glucan, and glycogen and is unable to nodulate Lotus tenuis. The nonnodulating phenotype of the pgm mutant was not due to the absence of glycogen, since a glycogen synthase (glgA) null mutant effectively nodulates this legume. In M. loti, pgm is part of the glycogen metabolism gene cluster formed by GlgP (glycogen phosphorylase), glgB (glycogen branching), glgC (ADP-glucose pyrophosphorylase), glgA, pgm, and glgX (glycogen debranching). The genes are transcribed as a single transcript from glgP to at least pgm under the control of a strong promoter (promoter I) upstream of glgP. An alternative promoter (promoter II), mapping in a 154-bp DNA fragment spanning 85 bp upstream of the glgA start codon and the first 69 bp of the glgA coding region, controls the expression of glgA and pgm, independently of the rest of the upstream genes. Primer extension experiments showed that transcription starts 19 bp upstream of the glgA start codon.

1,4-alpha-Glucan Branching Enzyme↗

PubMed1981

The structure determination of rabbit phosphoglucomutase.

Tetragonal crystals of rabbit phosphoglucomutase have been grown from solutions containing ammonium sulphate, polyethylene glycol solution and enzyme. There are two molecules, each of relative molecular mass 64 000 per asymmetric unit. A rotation function suggests that these are related by a twofold axis. X-ray diffraction data for five heavy-atom derivatives and native crystals have been collected by using oscillation photography. A tentative and partial solution of the KAu(CN)2 sites has been obtained. The enzyme in the native crystals is phosphorylated, but the phosphate can be removed without harm to the crystals. Similarly the essential Mg2+ ion can be removed or replaced by Zn2+. The enzyme is active in the native crystals.

Animals↗

PubMed1998

Molecular and biochemical characterization of cytosolic phosphoglucomutase in maize. Expression during development and in response to oxygen deprivation.

Phosphoglucomutase (PGM) catalyzes the interconversion of glucose (Glc)-1- and Glc-6-phosphate in the synthesis and consumption of sucrose. We isolated two maize (Zea mays L.) cDNAs that encode PGM with 98.5% identity in their deduced amino acid sequence. Southern-blot analysis with genomic DNA from lines with different Pgm1 and Pgm2 genotypes suggested that the cDNAs encode the two known cytosolic PGM isozymes, PGM1 and PGM2. The cytosolic PGMs of maize are distinct from a plastidic PGM of spinach (Spinacia oleracea). The deduced amino acid sequences of the cytosolic PGMs contain the conserved phosphate-transfer catalytic center and the metal-ion-binding site of known prokaryotic and eukaryotic PGMs. PGM mRNA was detectable by RNA-blot analysis in all tissues and organs examined except silk. A reduction in PGM mRNA accumulation was detected in roots deprived of O2 for 24 h, along with reduced synthesis of a PGM identified as a 67-kD phosphoprotein on two-dimensional gels. Therefore, PGM is not one of the so-called "anaerobic polypeptides." Nevertheless, the specific activity of PGM was not significantly affected in roots deprived of O2 for 24 h. We propose that PGM is a stable protein and that existing levels are sufficient to maintain the flux of Glc-1-phosphate into glycolysis under O2 deprivation.

Aerobiosis↗

PubMed2000

The plastidic phosphoglucomutase from Arabidopsis. A reversible enzyme reaction with an important role in metabolic control.

An Arabidopsis cDNA (AtPGMp) encoding the plastidic phosphoglucomutase (PGM) predicted a 623-amino acid protein with an N-terminal sequence typical of a plastid signal peptide. Expression of a recombinant protein in Escherichia coli confirmed its enzyme activity. The recombinant enzyme had an apparent K(m) value of 98.5 microM and a V(max) of 4.48 micromol min(-1) (mg protein)(-1). The Calvin cycle intermediates fructose-1,6-bisphosphate and ribulose-1, 5-bisphosphate exerted an inhibitory effect on PGM activity, supporting its proposed involvement in controlling photosynthetic carbon flow. A point mutation was identified in the AtPGMp gene of the Arabidopsis pgm-1 mutant. The mutation in the mutant transcript generated a stop codon at about one third of the wild-type open reading frame, and thus rendered the polypeptide nonfunctional. Storage lipid analysis of the pgm-1 mutant seeds showed a 40% reduction in oil content compared with that of wild type. Our results indicate that plastidic PGM is an important factor affecting carbon flux in triacylglycerol accumulation in oilseed plants, most likely through its essential role in starch synthesis.

Amino Acid Sequence↗

PubMed2002

Crystallization and preliminary X-ray diffraction studies of beta-phosphoglucomutase from Lactococcus lactus.

Beta-phosphoglucomutase (beta-PGM), a 28 kDa monomer, catalyzes the reversible conversion of beta-D-glucose-1-phosphate to beta-D-glucose-6-phosphate in maltose metabolism in a variety of organisms. Sequence analysis of beta-PGM indicates that it is a member of the haloacid dehalogenase (HAD) enzyme superfamily, which evolved to cleave C-Cl, C-P and C-OP bonds in a variety of substrates. beta-PGM has been crystallized using the hanging-drop method. Diffraction-quality crystals of the native protein have been obtained from two conditions, both belonging to space group P2(1)2(1)2(1), with unit-cell parameters a = 53.67, b = 92.78, c = 111.60 and a = 53.21, b = 57.01, c = 76.11 A. To solve the phase problem, selenomethionine (SeMet) containing beta-PGM crystals have been grown. The SeMet-containing crystals diffract to high resolution only when grown by microseeding with native crystals. A three-wavelength data set has been collected to 2.3 A on crystals of the SeMet-substituted beta-PGM. The structure solution is currently being attempted by the multiwavelength anomalous diffraction (MAD) phasing method.

Crystallization↗

PubMed1998

Long-term alcohol effects on hepatic phosphoglucomutase activities in relation to posttranslational modification of the protein.

ADP-ribosylation is a posttranslational protein modification catalyzed by two classes of enzymes: mono-ADP-ribosyltransferase and poly-ADP-ribose polymerases. We previously demonstrated that long-term alcohol intake remarkably enhanced an endogenous ADP-ribosylation of a 58 kDa protein in rat liver and also identified the 58 kDa protein as phosphoglucomutase (PGM). To assess biological significance of this phenomenon, we tested the effects of long-term alcohol intake on PGM activities in connection with posttranslational modification of the protein. ADP-ribosylation of PGM was mono- rather than poly-ADP-ribosylation. Also, nonenzymatic binding of ADP-ribose was excluded. It was of note that ADP-ribosylation of exogenous PGM was remarkably increased by adding rat liver plasma membranes, and that the extent of the increase was greater in alcohol-fed rats than in pair-fed controls. Furthermore, PGM activities were significantly increased after long-term alcohol intake concomitant with increased ADP-ribosyltransferase activities toward PGM. In view of the variety of roles of PGM in the liver, such as carbohydrate metabolism and Ca2+ homeostasis, it is tempting to speculate that increased ADP-ribosylation of PGM may play a role in long-term alcohol effects on hepatocytes.

ADP Ribose Transferases↗

PubMed1976

Polymorphism of phosphoglucomutase in a German breed cattle.

Haemolysates from cattle belonging to the Hochfleckvieh breed (N = 42), were studied for electrophoretic variation of phosphoglucomutase. Three phenotypes were observed which could be explained on the basis of two alleles PGM1A and PGM1B. The PGM1B frequency of 0.7325 is comparatively lower than in other breeds.

Alleles↗

PubMed1978

Phosphoglucomutase electrophoretic patterns of the loach Cobitis biwae.

Phosphoglucomutase of two groups of the loach Cobitis biwae, a fresh-water teleost, was examined by starch gel electrophoresis. Some of the fishes had six-banded electrophoretic patterns not observed in other loach species (e.g. Misgurnus anguillicaudatus and Cobitis delicata). The complexity of the pattern is explainable by an assumption that the loaches are tetraploid fishes. The result suggests that a diploid-tetraploid relationship exists within the species Cobitis biwae.

Alleles↗

PubMed1979

Geographical variation of lactate dehydrogenase and phosphoglucomutase in the loach Misgurnus anguillicaudatus.

One of the two loci controlling muscle lactate dehydrogenase (LDH) was shown to be polymorphic in the loach Misgurnus anguillicaudatus. The result of the survey on four populations suggests that the differences in the LDH gene frequencies are correlated with the geographical distribution of the loach. A fourth phosphoglucomutase allele (PGMD) was found in one of the loach populations examined.

Animals↗

PubMed2004

Temperature-mediated seasonal variation in phosphoglucomutase allozyme frequency in the yellow dung fly, Scathophaga stercoraria.

The allozyme genetic variability of various species is correlated with a variety of morphological, physiological and fitness-related traits. In particular, temperature can affect the fitness of insects through its influence on enzyme function. We examined the seasonal (12 days over 1 year) and daily (nine samples over each day) allozyme variation at the phosphoglucomutase (PGM) locus in one population of yellow dung flies (Scathophaga stercoraria; Diptera: Scathophagidae). PGM is of central functional importance in the mobilization of glycogen reserves for flight, and has been shown to affect larval growth at different temperatures in the laboratory. Based on a sample of over 3000 flies, we found a quadratic relationship, with a minimum at approximately 12 degrees C, between the frequency of the most common allele and temperature, primarily mediated by seasonal temperature variation. This could be caused by behavioural responses over the short-term, but over the year either variable viability or sexual selection probably operates on this locus, maintaining the existing polymorphism. These results call for further work on the functional differences between PGM allozyme genotypes.

Animals↗