Bacterial glycogen and plant starch biosynthesis

Iglesias, Alberto A.; Preiss, Jack

doi:10.1016/0307-4412(92)90191-n

Cited by 51 publications

(77 citation statements)

References 17 publications

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“…During cultivation of C. glutamicum in media containing sugars, we have recently observed synthesis and degradation of intracellular glycogen (Seibold et al, 2007). Glycogen consists of a-1,4-a-1,6-linked glucose residues (Manners, 1991), and serves as a major reserve polysaccharide in eukaryotes and in a variety of bacteria (Ball & Morell, 2003;Iglesias & Preiss, 1992). Although there have been some investigations of enzymes or genes involved in glycogen synthesis and degradation in other bacteria (Buschiazzo et al, 2004;Horcajada et al, 2006;Yeo & Chater, 2005), most studies have been done with Escherichia coli (Ballicora et al, 2003;Preiss, 1996).…”

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confidence: 99%

The glgX gene product of Corynebacterium glutamicum is required for glycogen degradation and for fast adaptation to hyperosmotic stress

Seibold

Eikmanns

2007

Microbiology

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Corynebacterium glutamicum cells growing in medium containing sugars accumulate glycogen in the early exponential-growth phase, and start to degrade this polymer at entry into the stationary phase. In a first attempt to investigate glycogen degradation, the C. glutamicum glgX gene, which encodes a protein with 46 % identity to the isoamylase-type debranching enzyme of Escherichia coli, was analysed, expressed and inactivated. The purified C. glutamicum gene product showed debranching activity towards glycogen, amylopectin and starch. Chromosomal inactivation of glgX in C. glutamicum wild-type led to slower growth and to a higher intracellular glycogen pool throughout growth, when compared to those in the parental strain. This result suggests that glycogen synthesis and degradation occur simultaneously in C. glutamicum. When exposed to hyperosmotic shock, C. glutamicum rapidly degrades glycogen, and at the same time, synthesizes the osmoprotectant trehalose. The glgX mutant, however, synthesized only minor amounts of trehalose throughout cultivation, and its growth ceased after hyperosmotic shock. Taken together, the results indicate that the glgX gene product is essential for glycogen degradation in C. glutamicum, that glycogen is constantly recycled in C. glutamicum, and that it serves as a carbon store for trehalose synthesis via the TreYZ pathway after hyperosmotic shock.

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Section: Introductionmentioning

confidence: 99%

The glgX gene product of Corynebacterium glutamicum is required for glycogen degradation and for fast adaptation to hyperosmotic stress

Seibold

Eikmanns

2007

Microbiology

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“…Many organisms, including plants, accumulate carbon and energy reserves to cope with starvation conditions temporarily present in the environment (42,72,73,78,88). The biosynthesis of ␣-1,4-polyglucans is a main strategy for such metabolic storage.…”

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ADP-Glucose Pyrophosphorylase, a Regulatory Enzyme for Bacterial Glycogen Synthesis

Ballícora

Iglesias

Preiss

2003

Microbiol Mol Biol Rev

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231

354

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The accumulation of α-1,4-polyglucans is an important strategy to cope with transient starvation conditions in the environment. In bacteria and plants, the synthesis of glycogen and starch occurs by utilizing ADP-glucose as the glucosyl donor for elongation of the α-1,4-glucosidic chain. The main regulatory step takes place at the level of ADP-glucose synthesis, a reaction catalyzed by ADP-Glc pyrophosphorylase (PPase). Most of the ADP-Glc PPases are allosterically regulated by intermediates of the major carbon assimilatory pathway in the organism. Based on specificity for activator and inhibitor, classification of ADP-Glc PPases has been expanded into nine distinctive classes. According to predictions of the secondary structure of the ADP-Glc PPases, they seem to have a folding pattern common to other sugar nucleotide pyrophosphorylases. All the ADP-Glc PPases as well as other sugar nucleotide pyrophosphorylases appear to have evolved from a common ancestor, and later, ADP-Glc PPases developed specific regulatory properties, probably by addition of extra domains. Studies of different domains by construction of chimeric ADP-Glc PPases support this hypothesis. In addition to previous chemical modification experiments, the latest random and site-directed mutagenesis experiments with conserved amino acids revealed residues important for catalysis and regulation

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“…For instance, the enzymes from heterotrophic bacteria such as Escherichia coli are regulated by intermediates of the glycolytic pathway, with Fru-1,6-P 2 as the main activator and AMP as the main inhibitor. On another hand, the ADP-Glc PPases from cells performing oxygenic photosynthesis and assimilating atmospheric CO 2 through the reductive pentose phosphate pathway or the Calvin cycle (specifically cyanobacteria, green algae, and photosynthetic tissues from higher plants) are activated by 3-phosphoglycerate and inhibited by P i (6).Except for some Bacillus species (5-7), prokaryotic ADP-Glc PPases are homotetramers, with the monomer being ϳ50 kDa (2,5,8,9). Characterized ADP-Glc PPases from higher plants are heterotetramers of two different but homologous subunits (2-6), the "small" or catalytic subunit (50 -54 kDa) and the "large" or regulatory subunit (51-60 kDa) (10).…”

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“…Except for some Bacillus species (5-7), prokaryotic ADP-Glc PPases are homotetramers, with the monomer being ϳ50 kDa (2,5,8,9). Characterized ADP-Glc PPases from higher plants are heterotetramers of two different but homologous subunits (2-6), the "small" or catalytic subunit (50 -54 kDa) and the "large" or regulatory subunit (51-60 kDa) (10).…”

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“…Most ADP-Glc PPases are allosterically regulated by small effector molecules. Although these vary according to the source, they are all intermediates of the principal carbon assimilation pathway in the respective cell (2)(3)(4)(5)(6). Thus, bacterial glycogen and plant starch syntheses are not modulated only by the availability of ATP but also by the accumulation of key metabolites that represent the carbon and energy balance within the cell.…”

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confidence: 99%

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Molecular Architecture of the Glucose 1-Phosphate Site in ADP-glucose Pyrophosphorylases

Bejar

Jin²,

Ballícora³

et al. 2006

Journal of Biological Chemistry

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ADP-Glc pyrophosphorylase (PPase), a key regulatory enzyme in the biosynthetic pathway of starch and bacterial glycogen, catalyzes the synthesis of ADP-Glc from Glc-1-P and ATP. A homology model of the three-dimensional structure of the Escherichia coli enzyme complexed with ADP-Glc has been generated to study the substrate-binding site in detail. A set of amino acids in the model has been identified to be in close proximity to the glucose moiety of the ADP-Glc ligand. ) was studied by site-directed mutagenesis through the characterization of the kinetic properties and thermal stability of the designed mutants. All purified alanine mutants had 1 or 2 orders of magnitude lower apparent affinity for Glc-1-P compared with the wild type, indicating that the selected set of amino acids plays an important role in their interaction with the substrate. These amino acids, which are conserved within the ADP-Glc PPase family, were replaced with other residues to investigate the effect of size, hydrophobicity, polarity, aromaticity, or charge on the affinity for Glc-1-P. In this study, the architecture of the Glc-1-P-binding site is characterized. The model overlaps with the Glc-1-P site of other PPases such as Pseudomonas aeruginosa dTDP-Glc PPase and Salmonella typhi CDPGlc PPase. Therefore, the data reported here may have implications for other members of the nucleotide-diphosphoglucose PPase family.The biosynthetic pathways of starch and bacterial glycogen are very similar (1). The initial and key regulatory step is the formation of the glucosyl donor molecule ADP-Glc from ATP and Glc-1-P via a reaction catalyzed by ADP-glucose pyrophosphorylase (PPase 4 ; glucose-1-phosphate adenylyltransferase, EC 2.7.7.27), with the requirement of a divalent cation (Mg 2ϩ ): ATP ϩ Glc-1-P 4 Mg 2ϩ 3 ADP-Glc ϩ PP i . Most ADP-Glc PPases are allosterically regulated by small effector molecules. Although these vary according to the source, they are all intermediates of the principal carbon assimilation pathway in the respective cell (2-6). Thus, bacterial glycogen and plant starch syntheses are not modulated only by the availability of ATP but also by the accumulation of key metabolites that represent the carbon and energy balance within the cell. For instance, the enzymes from heterotrophic bacteria such as Escherichia coli are regulated by intermediates of the glycolytic pathway, with Fru-1,6-P 2 as the main activator and AMP as the main inhibitor. On another hand, the ADP-Glc PPases from cells performing oxygenic photosynthesis and assimilating atmospheric CO 2 through the reductive pentose phosphate pathway or the Calvin cycle (specifically cyanobacteria, green algae, and photosynthetic tissues from higher plants) are activated by 3-phosphoglycerate and inhibited by P i (6).Except for some Bacillus species (5-7), prokaryotic ADP-Glc PPases are homotetramers, with the monomer being ϳ50 kDa (2,5,8,9). Characterized ADP-Glc PPases from higher plants are heterotetramers of two different but homologous subunits (2-6), the "small" or catal...

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Bacterial glycogen and plant starch biosynthesis

Cited by 51 publications

References 17 publications

The glgX gene product of Corynebacterium glutamicum is required for glycogen degradation and for fast adaptation to hyperosmotic stress

The glgX gene product of Corynebacterium glutamicum is required for glycogen degradation and for fast adaptation to hyperosmotic stress

ADP-Glucose Pyrophosphorylase, a Regulatory Enzyme for Bacterial Glycogen Synthesis

Molecular Architecture of the Glucose 1-Phosphate Site in ADP-glucose Pyrophosphorylases

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