Abstract
Glycogen is conventionally viewed as an energy reserve that can be rapidly mobilized for ATP production in higher organisms. However, several studies have noted that glycogen with short average chain length in some bacteria is degraded very slowly. In addition, slow utilization of glycogen is correlated with bacterial viability, that is, the slower the glycogen breakdown rate, the longer the bacterial survival time in the external environment under starvation conditions. We call that a durable energy storage mechanism (DESM). In this review, evidence from microbiology, biochemistry, and molecular biology will be assembled to support the hypothesis of glycogen as a durable energy storage compound. One method for testing the DESM hypothesis is proposed.
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Introduction
Bacterial energy reserves
In nature, (partially) free-living pathogens often encounter different types of stresses, such as hyperosmolarity, oxidative, DNA damage, and so on. Their survival depends on their ability to sense and respond to these changing stresses from time to time (Boor 2006). However, these functions require a comparatively large amount of energy, which is called energy of maintenance (Wilkinson 1963). Thus, an important factor for bacterial durability is their energy reserves, especially when considering that bacteria need to adapt to the large changes after shedding from hosts to the external environments and during invasion into hosts from external environments. Exceptions include, but are not limited to, those species that rely on spore formation to extend their survival in unfavorable conditions, such as Bacillus clausii and Clostridium botulinum. As a result, these bacteria may not require long-term energy reserves (also see the Electronic Supplementary Material).
So far, five major reserves have been identified as energy storage compounds in bacteria: triacylglycerols (TAGs), wax esters (WEs), polyhydroxybutyrate (PHB), polyphosphates (PolyPs), and glycogen. Although neutral lipids, TAG and WE, have high-energy capacity, their accumulations as intracellular lipid bodies are only found in a limited number of prokaryotes (Waltermann and Steinbuchel 2005; Kalscheuer 2010). PolyP and PHB are widespread polymers in bacteria. However, the linear structure of PHB makes it readily attacked by enzymes while PolyP can function as an ATP substitute (Zevenhuizen and Ebbink 1974; Kornberg et al. 1999). Thus, PolyP and PHB primarily act as short-term energy suppliers. However, these comparisons are relative and exceptions do exist, which we will talk about later. Unlike the other four molecules, glycogen is a widespread and large-molecular mass (107–108 Da) polymer in bacteria (Wilson et al. 2010). Glycogen also has a highly and randomly branched structure, which makes it a more flexible energy reserve than other storage compounds. This will be explored below. Currently, glycogen has been reported to exist in more than 50 different bacterial species across all bacterial classes (Preiss 2009). For this review, we constructed a set of glycogen Hidden Markov Models (HMMs) (Eddy 1998) based on the general glycogen metabolism genes (glgC, glgA, glgP, glgB, glgX) from Escherichia coli K12. Using these, we screened 1,202 high-quality annotated bacterial proteomes from high-quality automated and manual annotation of microbial proteomes (HAMAP http://expasy.org/sprot/hamap/bacteria.html) (Lima et al. 2009) for glycogen metabolism genes in order to see the theoretical distribution of glycogen in bacteria (p-value cutoff 10−16). In order to make sure our results are as accurate as possible, we also used protein annotations as references for HMM searching. We observed that 402 strains (245 species) have complete general genes for glycogen metabolism, while another 367 strains (234 species) do not have any of the genes (Electronic Supplementary Material).
Glycogen metabolism, bacterial lifestyle, and proteome sizes
Henrissat et al. screened 55 completely sequenced bacterial genomes and found that most of the free-living bacteria accumulate glycogen while those with parasitic lifestyles do not and concluded that glycogen accumulation could be a marker for bacterial parasitic behavior (Henrissat et al. 2002). Our study of the 1,202 bacteria in terms of existence or loss of glycogen metabolism pathways and bacterial lifestyle completes and extends the work of Henrissat et al. done on a more limited number of bacterial genomes. For example, most endosymbionts, such as Buchnera aphidicola and Wolbachia pipientis, and intracellular obligate pathogens, like Coxiella burneti and Orientia tsutsugamushi, have lost their glycogen synthesis and degradation abilities (see Electronic Supplementary Material for the complete list of bacterial lifestyles and distribution of glycogen metabolism pathway).
Genome reduction is correlated with bacterial lifestyle and habitat, which means that obligate intracellular pathogens are much more likely to have smaller genomes compared with free-living bacteria because potentially dispensable genes tend to be lost under selective pressure (Moran 2002; Sakharkar and Chow 2005). Based on these two theories, we compared the proteome sizes of bacteria with (402 proteome sizes) and without (367 proteome sizes) glycogen metabolism genes and found that average proteome size of the former group is significantly larger than that of the latter group (Fig. 1). Histograms of the two sets of bacteria give a detailed illustration of the distribution of proteome sizes (Fig. 2). Both suggest that bacteria with glycogen storage may have more varied lifestyles and occupy more diverse habitats and thus, on average, will be more durable. However, we must emphasize that there are exceptions. For example, Acinetobacter sp. and Burkholderia pseudomallei, which do not store glycogen at all but are able to utilize other energy storage compounds, are also rather durable in the external environment (Ishige et al. 2003; Inglis and Sagripanti 2006).
Durable energy storage mechanisms
Besides the existence or loss of glycogen metabolism pathways, glycogen branching structures vary. Certain types of glycogen are difficult to utilize and bacteria accumulating such glycogen are able to survive longer under starvation conditions when living freely in the external environment, while other types of glycogen are more easily broken down and the corresponding bacteria die at a higher rate when starved (Kim and Gadd 2008; Takata et al. 1998; Strange et al. 1961; Zevenhuizen and Ebbink 1974; Boylen and Mulks 1978; Strange 1968). Based on this phenomenon, we propose a hypothesis called the durable energy storage mechanism (DESM), by which we mean a storage compound forces bacteria to utilize the compound more slowly, e.g. due to steric inhibition, and thus enhances bacterial survival ability.
Studies of glycogen conformation versus degradation rate have shed some light on the relationship (Zevenhuizen and Ebbink 1974; Boylen and Mulks 1978; Takata et al. 1998), although there is as yet no direct experimental evidence. However, this inferred relationship gives us a starting point to look for more persuasive evidence for the existence of DESMs. In this review, we will look deeper into glycogen structure and bring together evidence from different fields to construct a framework for our DESM hypothesis. It is worth mentioning that glycogen is not the only candidate for the DESM hypothesis. WE is able to store more energy than TAG on a weight basis and is more resistant to degradation and oxidation, which could prolong bacterial survival during starvation and/or desiccation conditions (Finkelstein et al. 2010; Gurr et al. 2002). For example, some strains of Acinetobacter, e.g., Acinetobacter baumannii—a durable nosocomial pathogen—accumulate WE but not glycogen as an energy reserve (Ishige et al. 2003). Although the relationship between bacterial survival ability and WE still requires further exploration, it is reasonable for us to consider it as a possible candidate for our DESM hypothesis due to its physiochemical characteristics. However, in this review, we will focus on the more widespread bacterial molecule, glycogen.
Glycogen structure and its durability
Glycogen has been widely identified in and isolated from animals, fungi, and bacteria (Wilson et al. 2010). It is a water-soluble polymer consisting of α-d-glucosyl units. These units are connected together by α-1,4-glycosidic linkages to form oligosaccharide chains, with α-1,6-glycosidic linkages at branching points (Manners 1991). Unlike branches in amylopectin, which are discontinuously dispersed so amorphous and crystalline lamellae alternate, branches in glycogen are randomly and extensively distributed; no crystalline portion has ever been detected (D’Hulst and Merida 2010; Ball and Morell 2003), although some theoretical models assume that branched chains in glycogen are regularly distributed (Meléndez-Hevia et al. 1993). Using scanning tunneling microscopy Yang et al. (1990) reported that the glycogen molecule has a laminated structure.
Since glycogen was first extracted from liver tissue by Claude Bernard in 1857, its structure and function have been extensively studied (Young 1957). Although many models have been constructed, there is still no accurate description for glycogen structure due to its high molecular weight and random branches (Gunja-Smith et al. 1970; Manners 1991, 1957; Sullivan et al. 2010; Melendez et al. 1999). However, its basic framework has long been solved, and many parameters have been devised to describe glycogen structure, which are exterior chain (EC), interior chain, degree of polymerization, average chain length (ACL), etc. For details, please see the review paper by Manners (1991). Of all these parameters, glycogen ACL is one of the core factors impacting glycogen degradation rate because it influences the percentage of α-1,6-glycosidic linkages and therefore the interaction with glycogen degrading enzymes (Park and Rollings 1995, 1994). Thus, ACL determines the durable characteristics of glycogen.
Besides its function in balancing glucose homeostasis of blood, in animals, glycogen functions as a rapid and transient energy supplier for muscle activity (Kollberg et al. 2007; Melendez et al. 1999). Considering the consistency of its structural characteristics (Table 1) and the similarity of metabolic regulation, it is reasonable to conclude that glycogen is a transient energy source in animals. However, this conclusion may be not appropriate for bacterial glycogen due to the simpler structures and low energy requirements of bacteria, the wide variation of glycogen ACL (Table 1), and relatively low-level control mechanism of glycogen metabolism when compared with hormone control in higher organisms (Wilson et al. 2010; Oz et al. 2007; Tsintzas and Williams 1998).
Experimental data from different sources, summarized in Table 2, reveal a suggestive relationship between glycogen ACL and bacterial survival ability. For example, after examining glycogen metabolism in Aerobacter aerogenes (ACL = 13) and Escherichia coli (ACL = 12), Strange (1968) concluded that “a feature of glycogen reserves in bacteria is their rapid depletion during starvation which suggests that any contribution glycogen makes towards maintenance and survival is of short duration”. In contrast, glycogen in Arthrobacter (ACL = 7) and Mycobacterium (ACL = 7) is broken down very slowly (Zevenhuizen and Ebbink 1974). Coincidentally, both of the latter survive for a long time under starvation conditions (Zevenhuizen and Ebbink 1974; Boylen and Mulks 1978). Kim and Gadd (2008) also reports that Arthrobacter globiformis (ALC = 6.6) utilizes glycogen slowly and stays viable for a long time under starvation conditions while E. coli (ACL = 12) uses glycogen at a high rate and does not survive very long. In addition, Takata et al. (1998) also noted the faster degradation of glycogen in Bacillus stearothermophilus (ACL = 21) when compared with E. coli (ACL = 12).
Structural analysis of the bacterial glycogens above reveals a relationship between glycogen ACL and bacterial durability. It seems that short ACL (SACL) glycogen enhances bacterial durability under starvation conditions. Thus, what is it about SACL glycogen that makes it more difficult to break down? ACL and percentage of glycosidic linkages are interconnected. That is, for a glycogen with the same molecular weight, shorter ACL will lead to higher percentage of 1,6-glycosidic linkages, and vice versa. In this part, we discuss the influence of 1,6-glycosidic linkages on glycogen durability. The effects of glycogen ACL on glycogen durability will be explored in the next part, when talking about the substrate-enzyme interactions.
Takahash and Ono (1966) studied the heat of hydrolysis (ΔH) of α-1,4- and α-1,6-glucosidic linkages by calorimetry and found that ΔH 1,4 was −1,100 cal/mol and ΔH 1,6 was +1,300 cal/mol at 25°C, which was further confirmed by Tewari and Goldberg (1989). Although these results were obtained by studying maltose (disaccharides linked with α-1,4-glycosidic bonds) and isomaltose (disaccharides linked by α-1,6-glycosidic bonds), the heat of hydrolysis of polysaccharides is an additive function of the thermal data of the individual linkages (Takahash and Ono 1966). Thus, it is reasonable to apply these thermal data to glycogen analysis. Glycogen branching enzyme (EC = 2.4.1.18) (GBE), the principal enzyme responsible for the formation of branched side chains has two functions: breaking the α-1,4-glycosidic linkages from one chain and transferring oligosaccharides to the same or other chains by forming α-1,6-glycosidic linkages (Abad et al. 2002). In this process, one α-1,4-linkage is broken and one α-1,6-linkage is generated. Thus, the whole process will release −2,400 cal/mol energy, and the branching reaction is thermodynamically favored. As French (1964) concluded, “in an enzymically catalyzed system, if there was a free opportunity to exchange α-1,4- to α-1,6-bonds reversibly, the equilibrium mixture would probably contain 70–90% of α-1,6-bonds.” The reason why this does not happen in glycogen is probably due to its spatial self-limitation, that is, a large number of α-1,6-glycosidic bonds leads to more branches and so higher density, which restricts further branching of glycogen (Meléndez-Hevia et al. 1993). However, a specific explanation still requires further research.
On the other hand, ΔH can also be used as an indicator for determining the relative stabilities of isomeric compounds (Gallagher et al. 1998). For example, branched hydrocarbon isomers release more heat when forming than less branched and straight chains. Experiments and theoretical calculation have shown that branched hydrocarbon isomers are more energetically stable than straight chains and that isomer stability increases with branching of the hydrocarbon (Laidig 1991). Thus, from the standpoint of glycogen synthesis, we infer that highly branched glycogen is more stable than less branched glycogen and therefore more durable when undergoing degradation because more alpha-1,6-glycosidic linkages exist in hyperbranched glycogen. Experiments are required to confirm this conclusion.
Acid hydrolysis of glycogen excludes the influences of substrate–enzyme interactions and has revealed the inherent characteristics of glycogen durability. It was found that the non-reducing end α-1,4-linkages are hydrolyzed at a faster rate than the other α-1,4-linkages, and α-1,4-linkages are hydrolyzed four times faster than α-1,6-linkages at 100°C, and seven times faster at room temperature (Wolfrom et al. 1951; Erlander and French 1958). In order to confirm that linkage differences would be sufficient to change degradation rates, one need only look at the hydrolysis of various polysaccharides in acid solution (7.7 N HCl at 30°C), including amylose, amylopectin, glycogen, limit dextrin (a more highly branched polysaccharide than glycogen), and dextran (polysaccharide with α-1,6-glycosidic linkages only). Results showed a significant correlation between percentage of α-1,6-linkages in polysaccharide and resistance to acid hydrolysis (Swanson and Cori 1948). In sum, glycogen with higher percentage of α-1,6-glycosidic linkages should be more thermodynamically stable and harder to break down.
Glycogen metabolism and enzymology
Enzymatic reaction kinetics is known to be affected by substrate structures (Park et al. 1988). Since glycogen is a polydisperse polymer, we would expect that its conformation, which is determined by its average chain length (Table 1), has a significant influence on the substrate-enzyme interactions and will further influence its degradation rate. Five enzymes are generally important in the process of glycogen metabolism, although some of them are not essential in some bacteria: ADP-Glucose pyrophosphorylase (EC = 2.7.7.27), glycogen synthase (EC = 2.4.1.21), α-1,4-glucan-branching enzyme (EC = 2.4.1.18), glycogen phosphorylase (EC = 2.4.1.1) and glycogen debranching enzyme (EC = 3.2.1.-) (Ballicora et al. 2003; Ball and Morell 2003; Buschiazzo et al. 2004; Abad et al. 2002; Alonso-Casajus et al. 2006; Dauvillee et al. 2005). Figure 3 shows a schematic model for glycogen metabolism. Although each enzyme has its unique function, study of the corresponding structural genes shows that these enzymes work together to maintain a balance between glycogen biosynthesis and degradation, which leads to the different glycogen conformations in bacteria (Ballicora et al. 2003; Ball and Morell 2003; Buschiazzo et al. 2004; Abad et al. 2002; Alonso-Casajus et al. 2006; Dauvillee et al. 2005). In addition, variation of glycogen structure is also reported to correlate with development stages and growth conditions of microorganisms (Yoo et al. 2007; Norrman et al. 1975). By reviewing the interactions of α-amylase (EC = 3.2.1.1), glycogen phosphorylase, and glycogen debranching enzyme with various polysaccharides, we see how substrate structures are related to degradation rates.
α-Amylase is an enzyme that hydrolyses α-1,4-glycosidic linkages in oligosaccharides and polysaccharides (Park and Rollings 1994). It mainly exists in animals and plants and is not involved in bacterial interior glycogen breakdown. In fact, many bacteria secrete α-amylase into the environment to digest exogenous amylopectin and amylose (Shelburne et al. 2009; Raha et al. 1992) and isoamylase to digest glycogen, amylopectin, and their beta-limit dextrins (Amemura et al. 1988), while pullulanase is secreted to the outer membrane to break down pullulan, amylopectin, and glycogen (Kornacker and Pugsley 1990). In addition, both E. coli α-amylase over-expressors and mutants impaired in α-amylase have normal glycogen content (Eydallin et al. 2007b). However, α-amylase is a good example to explain how substrate structure can influence its degradation rate when interacting with enzymes. Unlike β-amylase (EC = 3.2.1.1) and glycogen phosphorylase that only work on the non-reducing ends of glycogen, α-amylase catalyzes the breakdown of α-1,4-glycosidic bonds inside polysaccharides and forms α-amylase resistant macro-dextrin and oligosaccharides (Brammer et al. 1972). In order to understand the effects of branching substrate on α-amylase activity, it would be much clearer if we had experimental data on α-amylolysis of glycogens with different branching degrees. However, no such experiments have ever been done. Park et al. (1988) studied this problem by using three closely related polysaccharides, amylose, amylopectin, and glycogen, the main difference being their average chain lengths. In addition, they used aqueous size exclusion chromatography with low-angle laser light scattering to detect polysaccharide molecular weights and distribution of branching characteristics. Reaction rates of polysaccharide amylolysis decreased with the increase of branching degree of polysaccharides, that is, decrease of average chain length (Park and Rollings 1994, 1995). Further kinetic modeling based on the data obtained above agreed well with experimental data, which implied a significant relationship between enzyme action and structural properties of polymeric substrate (Park and Rollings 1994, 1995).
Average chain length of glycogen also has a significant effect on the activities of glycogen phosphorylase and debranching enzyme. It has generally been accepted that glycogen phosphorylase in bacteria degrades glycogen from non-reducing ends of the outer layer down to a length of four glucosyl residues away from the first branching points encountered by the enzyme (Alonso-Casajus et al. 2006). Branched chains less than or equal to four glucosyl residues are highly resistant to phosphorylase and can only be degraded by a glycogen debranching enzyme at a comparatively lower rate (Dauvillee et al. 2005; Kim and Gadd 2008). In addition, branched chains with more than four glucosyl units cannot be catalyzed by glycogen debranching enzyme, which avoids generating an extensive futile cycle during glycogen synthesis, because branching enzyme transfers oligosaccharides with 5 to 11 glucosyl residues (Dauvillee et al. 2005). For example, Takata et al. (1998) shows that glycogen phosphorylase has a high affinity to glycogen if the average chain length is longer. Recall that the ACL of glycogen in B. stearothermophilus is 21 but in E. coli it is only 11–14. Experiments revealed that the affinity of glycogen phosphorylase for E. coli glycogen is comparatively lower while glycogen phosphorylase in B. stearothermophilus has about 100-fold higher affinity to glycogen and higher specific activity (Takata et al. 1998). Similarly, the activity of glycogen phosphorylase in E. coli is relatively higher than that in Arthrobacter spp. (ACL 7–9) (Kim and Gadd 2008). In sum, SACL glycogen is harder to degrade than glycogen with normal or longer ACL.
Glycogen metabolism-related genes and glycogen structure
With the development of molecular biology, more and more effort has been put into the study of structural genes of glycogen metabolism and their influence on glycogen structure (Buschiazzo et al. 2004; Dauvillee et al. 2005; Alonso-Casajus et al. 2006; Ballicora et al. 2003; Binderup et al. 2000). The corresponding genes for enzymes of glycogen metabolism are glgC, glgA, glgB, glgP, glgX, respectively (Fig. 3). In addition, although the organization of the genes involved in glycogen metabolism differs across bacterial species, the genes are generally organized in one or more operons (Cho et al. 2008). For example, they are organized in a single operon in E. coli: glgBXCAP and, within glgC, an alternative suboperonic promoter further directs glgAP expression (Montero et al. 2010). Two other related genes, glgD and glgS, are also found in bacteria. However, they are not essential for most glycogen-producing bacteria. glgD is a gene for the biosynthesis of a subunit of a heterotetrameric ADP-Glucose pyrophosphorylase, while glgS is able to stimulate glycogen biosynthesis when overexpressed (Kozlov et al. 2004; Takata et al. 1997).
Recent research has confirmed that glycogen metabolism is a sophisticated network and is highly interconnected with many cellular processes (Eydallin et al. 2007b; Wilson et al. 2010). In this part, we will not look into the network as a whole because it is not related to our topic. Instead, we focus on the five important genes and review their effects on glycogen structure when intentionally mutated. Manipulation of glycogen-related genes provides us with a direct and convenient method to test the glycogen-related DESM hypothesis (other DESMs are still under investigation).
GlgP and GlgX are essential for the degradation of glycogen. Deletion would lead to the over-accumulation of glycogen (Eydallin et al. 2007b). Bacterial strains with mutations in these genes are unable to utilize glycogen properly, and both of the gene products do influence the structure of glycogen. glgP mutants of E. coli accumulate glycogen with longer average chain length while glgX mutants have shorter chains in the outermost layer of glycogen (Alonso-Casajus et al. 2006; Dauvillee et al. 2005). On the other hand, mutation of glgA would lead to the absence of glycogen because GlgA is responsible for the elongation of linear chains, so without it, there would be no glycogen (Eydallin et al. 2007b). It is worth mentioning that, although glgC, encoding ADP-glucose (ADPG) pyrophosphorylase (E.C.2.7.7.9) that converts glucose-1-phosphate to ADPG, is an important source for ADPG accumulation, it is not an essential one. Recent studies have shown that enterobacteria have more than one source of ADPG for glycogen biosynthesis, but the additional sources have not yet been identified (Moran-Zorzano et al. 2007; Eydallin et al. 2007a). Martin et al. also pointed out that a GlgC is only essential for the first of the two phases of glycogen synthesis in Streptomyces coelicolor A3(2) (Martin et al. 1997).
Thus, to address average chain length, only glgB, encoding glycogen branching enzyme, is suitable for genetic manipulation because glgB mutation will lead to the variation of average chain length of glycogen without impacting the synthesis and utilization pathways (Lares et al. 1974; Binderup et al. 2000, 2002; Guan et al. 1995; Devillers et al. 2003). It has also been observed that branching enzymes from different sources show considerable variation of specific activities, chain transfer patterns, and substrate preferences of branching enzymes (Binderup et al. 2000). Bacteria without glgB tend to produce amylose-like polysaccharide instead of hyper-branched glycogen, and the amount of glycogen produced is much less (Lares et al. 1974). In addition, recent studies have revealed that progressively reducing the length of N-terminal domain of glycogen branching enzyme of E. coli results in the variation of chain transfer pattern, which further impacts the distribution of chain lengths in glycogen, that is, glycogen ACL (Binderup et al. 2000, 2002; Devillers et al. 2003). Finally, the type of N-terminal domain (unmodified) will also have an impact on glycogen ACL (Palomo et al. 2009). However, all these results were obtained by in vitro experiments, where engineered glycogen branching enzymes (progressively N-terminal truncation or extraneous N-terminal) were expressed in bacteria and then extracted to react with amylose in vitro (Devillers et al. 2003; Palomo et al. 2009). Based on these experimental data, one could manipulate the structure of glycogen by changing the length of GlgB in E. coli or construct hybrid GlgB by inserting short-chain preferred N-terminal domain, while other factors are kept constant. In this way, average chain length is the single variable but the total amount of glycogen is not changed much by the GlgB mutation. Then, one can study the viability of E. coli under starvation conditions and see the effects that glycogens with different ACL have on the survival time of E. coli.
Previous work done by Devillers et al. (2003) showed that branching enzymes with N-terminal 112 residues deleted (Nd1–112) had lower catalytic efficiency than wild-type branching enzymes, while their substrate specificity was the same. A histogram shows the distribution of chain lengths for different N-terminal deletions (Fig. 4) (Devillers et al. 2003). Below are the formulas (formula a and formula b) calculating the weighted ACL for the wild-type and Nd1–112 deletion strains. Numbers used to calculate glycogen ACL are estimated based on the histogram (Fig. 4).
Formula a. Glycogen ACL of WT strain
Formula b. Glycogen ACL of Nd1–112 strain
Specifically, progressively reducing the length of GBE N terminus leads to the shift of distribution of the transferred chains toward longer lengths in vitro. Palomo et al. (2009) constructed chimeric GBEs from Deinococcus geothermalis and Deinococcus radiodurans to study the effects N-domain had on the structure of glycogen, results of which indicated that the N-terminus of this enzyme determines not only glycogen branching pattern but also substrate specificity. The latter conclusion is inconsistent with the result obtained from E. coli experiments mentioned above (Binderup et al. 2000).
Conclusions and prospects
Glycogen is a highly branched homopolysaccharide that is widely distributed across bacterial species as an energy and carbon source. Moreover, loss of glycogen metabolism has been considered as a common marker for parasitic behavior, and most of these parasitic bacteria are either obligate intracellular pathogens or symbionts within hosts. This review reveals that bacterial glycogen with different ACL degrades at different rates. That is, the shorter the average chain length, the slower the breakdown rate, which in turn enhances bacterial durability. We call this enhancement a DESM. Finally, a feasible method is proposed to test glycogen as a durable energy storage compound.
References
Abad MC, Binderup K, Rios-Steiner J, Arni RK, Preiss J, Geiger JH (2002) The X-ray crystallographic structure of Escherichia coli branching enzyme. J Biol Chem 277:42164–42170
Abdelakher M, Smith F (1951) The repeating unit of glycogen. J Am Chem Soc 73:994–996
Alonso-Casajus N, Dauvillee D, Viale AM, Munoz FJ, Baroja-Fernandez E, Moran-Zorzano MT, Eydallin G, Ball S, Pozueta-Romero J (2006) Glycogen phosphorylase, the product of the glgP gene, catalyzes glycogen breakdown by removing glucose units from the nonreducing ends in Escherichia coli. J Bacteriol 188:5266–5272
Amemura A, Chakraborty R, Fujita M, Noumi T, Futai M (1988) Cloning and nucleotide sequence of the isoamylase gene from Pseudomonas amyloderamosa SB-15. J Biol Chem 263:9271–9275
Ball SG, Morell MK (2003) From bacterial glycogen to starch: Understanding the biogenesis of the plant starch granule. Annu Rev Plant Biol 54:207–233
Ballicora MA, Iglesias AA, Preiss J (2003) ADP-glucose pyrophosphorylase, a regulatory enzyme for bacterial glycogen synthesis. Microbiol Mol Biol Rev 67:213–225
Bender H (1979) Glycogen from Klebsiella pneumoniae M5 al and Escherichia coli K12. Appl Microbiol Biotechnol 8:279–287
Binderup K, Mikkelsen R, Preiss J (2000) Limited proteolysis of branching enzyme from Escherichia coli. Arch Biochem Biophys 377:366–371
Binderup M, Mikkelsen R, Preiss J (2002) Truncation of the amino terminus of branching enzyme changes its chain transfer pattern. Arch Biochem Biophys 397:279–285
Boeck B, Schinzel R (1998) Growth dependence of alpha-glucan phosphorylase activity in Thermus thermophilus. Res Microbiol 149:171–176
Boor KJ (2006) Bacterial stress responses: what doesn’t kill them can make them stronger. Plos Biol 4:18–20
Boylen CW, Mulks MH (1978) Survival of Coryneform bacteria during periods of prolonged nutrient starvation. J Gen Microbiol 105:323–334
Brammer GL, Rougvie MA, French D (1972) Distribution of alpha-amylase-resistant regions in the glycogen molecule. Carbohydr Res 24:343–354
Builder JE, Walker GJ (1970) Metabolism of the reserve polysaccharide of Streptococcus mitis. Properties of glycogen synthetase. Carbohydr Res 14:35–51
Buschiazzo A, Ugalde JE, Guerin ME, Shepard W, Ugalde RA, Alzari PM (2004) Crystal structure of glycogen synthase: homologous enzymes catalyze glycogen synthesis and degradation. EMBO J 23:3196–3205
Chao L, Bowen CC (1971) Purification and properties of glycogen isolated from a blue-green alga, Nostoc muscorum. J Bacteriol 105:331–338
Cho KM, Lim WJ, Math RK, Islam SMA, Hong SJ, Kim H, Yun HD (2008) Comparative analysis of the glg operons of Pectobacterium chrysanthemi PY35 and other prokaryotes. J Mol Evol 67:1–12
D’Hulst C, Merida A (2010) The priming of storage glucan synthesis from bacteria to plants: current knowledge and new developments. New Phytol 188:13–21
Dauvillee D, Kinderf IS, Li ZY, Kosar-Hashemi B, Samuel MS, Rampling L, Ball S, Morell MK (2005) Role of the Escherichia coli glgX gene in glycogen metabolism. J Bacteriol 187:1465–1473
Devillers CH, Piper ME, Ballicora MA, Preiss J (2003) Characterization of the branching patterns of glycogen branching enzyme truncated on the N-terminus. Arch Biochem Biophys 418:34–38
Eddy SR (1998) Profile hidden Markov models. Bioinformatics 14:755–763
Erlander SR, French D (1958) Acid hydrolysis and molecular weights of various corn amylopectin and glycogen. J Polym Sci 32:291–316
Eydallin G, Moran-Zorzano MT, Munoz FJ, Baroja-Fernandez E, Montero M, Alonso-Casajus N, Viale AM, Pozueta-Romero J (2007a) An Escherichia coli mutant producing a truncated inactive form of GlgC synthesizes glycogen: Further evidences for the occurrence of various important sources of ADPglucose in enterobacteria. FEBS Lett 581:4417–4422
Eydallin G, Viale AM, Moran-Zorzano MT, Munoz FJ, Montero M, Baroja-Fernandez E, Pozueta-Romero J (2007b) Genome-wide screening of genes affecting glycogen metabolism in Escherichia coli K-12. FEBS Lett 581:2947–2953
Finkelstein DB, Brassell SC, Pratt LM (2010) Microbial biosynthesis of wax esters during desiccation: Adaptation for colonization of the earliest terrestrial environments? Geology 38:247–250
French D (1964) Structure of glycogen and its amylolytic degradation. In: Whelan WJ (ed) Control of Glycogen Metabolism. Churchill, London, pp 7–28
Gallagher PK, Brown ME, Kemp RB (1998) Handbook of thermal analysis and calorimetry. Elsevier, Amsterdam
Guan H, Kuriki T, Sivak M, Preiss J (1995) Maize branching enzyme catalyzes synthesis of glycogen-like polysaccharide in glgB-deficient Escherichia coli. Proc Natl Acad Sci USA 92:964–967
Gunja-Smith Z, Marshall JJ, Mercier C, Smith EE, Whelan WJ (1970) A revision of the Meyer-Bernfeld model of glycogen and amylopectin. FEBS Lett 12:101–104
Gurr MI, Harwood JL, Frayn KN (2002) Lipid biochemistry, 5th edn. Blackwell, Oxford
Hara F, Akazawa T, Kojima K (1973) Glycogen biosynthesis in Chromatium strain D: I. characterization of glycogen. Plant Cell Physiol 14:737–745
Henrissat B, Deleury E, Coutinho PM (2002) Glycogen metabolism loss: a common marker of parasitic behaviour in bacteria? Trends Genet 18:437–440
Inglis TJJ, Sagripanti JL (2006) Environmental factors that affect the survival and persistence of Burkholderia pseudomallei. Appl Environ Microbiol 72:6865–6875
Ishige T, Tani A, Sakai YR, Kato N (2003) Wax ester production by bacteria. Curr Opin Microbiol 6:244–250
Kalscheuer R (2010) Genetics of wax ester and triacylglycerol biosynthesis in bacteria. In: Timmis KN (ed) Handbook of hydrocarbon and lipid microbiology, 1st edn. Springer, New York, pp 527–535
Kamio Y, Terawaki Y, Nakajima T, Matsuda K (1981) Structure of glycogen produced by Selenomonas ruminantium. Agric Biol Chem 45:209–216
Kent PW, Stacey M (1949) Studies in the glycogen of M. Tuberculosis (human strain). Biochim Biophys Acta 3:641–647
Kim BH, Gadd GM (2008) Bacterial physiology and metabolism. Cambridge University Press, Cambridge
Kollberg G, Tulinius M, Gilljam T, Ostman-Smith I, Forsander G, Jotorp P, Oldfors A, Holme E (2007) Cardiomyopathy and exercise intolerance in muscle glycogen storage disease 0. N Engl J Med 357:1507–1514
Konig H, Skorko R, Zillig W, Reiter WD (1982) Glycogen in thermoacidophilic archaebacteria of the genera Sulfolobus, Thermoproteus, Desulfurococcus and Thermococcus. Arch Microbiol 132:297–303
Kornacker MG, Pugsley AP (1990) Molecular characterization of pulA and its product, pullulanase, a secreted enzyme of Klebsiella pneumoniae UNF5023. Mol Microbiol 4:73–85
Kornberg A, Rao NN, Ault-Riche D (1999) Inorganic polyphosphate: a molecule of many functions. Annu Rev Biochem 68:89–125
Kozlov G, Elias D, Cygler M, Gehring K (2004) Structure of GlgS from Escherichia coli suggests a role in protein-protein interactions. BMC Biol 2:10
Laidig KE (1991) Energetics of hydrocarbon branching. J Phys Chem 95:7709–7713
Lappinscott HM, Cusack F, Macleod A, Costerton JW (1988) Starvation and nutrient resuscitation of Klebsiella pneumoniae isolated from oil well waters. J Appl Bacteriol 64:541–549
Lares C, Frixon C, Creuzet-Sigal N, Thomas P (1974) Characterization and ultrastructure of mutants of Escherichia coli deficient in alpha-1,4-glucan-alpha-1,4-glucan 6-glycosytransferase (branching enzyme). J Gen Microbiol 82:279–293
Lima T, Auchincloss AH, Coudert E, Keller G, Michoud K, Rivoire C, Bulliard V, de Castro E, Lachaize C, Baratin D, Phan I, Bougueleret L, Bairoch A (2009) HAMAP: a database of completely sequenced microbial proteome sets and manually curated microbial protein families in UniProtKB/Swiss-Prot. Nucleic Acids Res 37:D471–D478
Lopez NI, Ruiz JA, Mendez BS (1998) Survival of poly-3-hydroxybutyrate-producing bacteria in soil microcosms. World J Microbiol Biotechnol 14:681–684
Lou J, Dawson KA, Strobel HJ (1997) Glycogen formation by the ruminal bacterium Prevotella ruminicola. Appl Environ Microbiol 63:1483–1488
Manners DJ (1957) The molecular structure of glycogens. Adv Carbohydr Chem Biochem 12:261–298
Manners DJ (1991) Recent Developments in our understanding of glycogen structure. Carbohydr Polym 16:37–82
Martin MC, Schneider D, Bruton CJ, Chater KF, Hardisson C (1997) A glgC gene essential only for the first of two spatially distinct phases of glycogen synthesis in Streptomyces coelicolor A3(2). J Bacteriol 179:7784–7789
Melendez R, Melendez-Hevia E, Canela EI (1999) The fractal structure of glycogen: A clever solution to optimize cell metabolism. Biophys J 77:1327–1332
Meléndez-Hevia E, Waddell TG, Shelton ED (1993) Optimization of molecular design in the evolution of metabolism: the glycogen molecule. Biochem J 295:477–483
Montero M, Almagro G, Eydallin G, Viale AM, Muñoz FJ, Bahaji A, Li J, Rahimpour M, Baroja-Fernández E, Pozueta-Romero J (2010) Escherichia coli glycogen genes are organized in a single glgBXCAP transcriptional unit possessing an alternative suboperonic promoter within glgC that directs glgAP expression. Biochem J 433:107–117
Moran NA (2002) Microbial minimalism: Genome reduction in bacterial pathogens. Cell 108:583–586
Moran-Zorzano MT, Alonso-Casajus N, Munoz FJ, Viale AM, Baroja-Fernandez E, Eydallin G, Pozueta-Romero J (2007) Occurrence of more than one important source of ADPglucose linked to glycogen biosynthesis in Escherichia coli and Salmonella. FEBS Lett 581:4423–4429
Norrman J, Wober G, Cantino EC (1975) Variation in average unit chain-length of glycogen in relation to developmental stage in Blastocladiella Emersonii. Mol Cell Biochem 9:141–148
Oz G, Seaquist ER, Kumar A, Criego AB, Benedict LE, Rao JP, Henry PG, Van De Moortele PF, Gruetter R (2007) Human brain glycogen content and metabolism: implications on its role in brain energy metabolism. Am J Physiol Endocrinol Metab 292:E946–E951
Palomo M, Kralj S, van der Maarel MJEC, Dijkhuizen L (2009) The unique branching patterns of Deinococcus glycogen branching enzymes are determined by their N-terminal domains. Appl Environ Microbiol 75:1355–1362
Park JT, Rollings JE (1994) Effects of substrate branching characteristics on kinetics of enzymatic depolymerizaion of mixed linear and branched polysaccharides: I. amylose/amylopectin alpha-amylolysis. Biotechnol Bioeng 44:792–800
Park JT, Rollings JE (1995) Effects of substrate branching characteristics on kinetics of enzymatic depolymerization of mixed linear and branched polysaccharides: II. amylose/glycogen alpha-amylolysis. Biotechnol Bioeng 46:36–42
Park JT, Yu LP, Rollings JE (1988) Substrate structural effects on enzymatic depolymerization of amylose, amylopectin, and glycogen. Ann N Y Acad Sci 542:53–60
Preiss J (2009) Glycogen Biosynthesis. In: Schaechter M (ed) Encyclopedia of Microbiology, 3rd edn. Elsevier, Oxford, pp 145–158
Raha M, Kawagishi I, Muller V, Kihara M, Macnab RM (1992) Escherichia coli produces a cytoplasmic alpha-amylase, AmyA. J Bacteriol 174:6644–6652
Sakharkar KR, Chow VT (2005) Strategies for genome reduction in microbial genomes. Genome Inform 16:69–75
Scherp HW (1955) Neisseria and Neisserial infections. Annu Rev Microbiol 9:319–334
Shelburne SA, Keith DB, Davenport MT, Beres SB, Carroll RK, Musser JM (2009) Contribution of AmyA, an extracellular alpha-glucan degrading enzyme, to group A streptococcal host-pathogen interaction. Mol Microbiol 74:159–174
Strange RE (1968) Bacterial glycogen and survival. Nature 220:606–607
Strange RE, Ness AG, Dark FA (1961) Survival of stationary phase Aerobacter aerogenes stored in aqueous suspension. J Gen Microbiol 25:61–67
Sullivan MA, Vilaplana F, Cave RA, Stapleton D, Gray-Weale AA, Gilbert RG (2010) Nature of alpha and beta particles in glycogen using molecular size distributions. Biomacromolecules 11:1094–1100
Swanson MA, Cori CF (1948) Studies on the structure of polysaccharides: acid hydrolysis of starch-like polysaccharides. J Biol Chem 172:797–804
Takahash K, Ono S (1966) Calorimetric studies on hydrolysis of glucosides. IV. calorimetric determination of alpha-1,4 glucosidic linkage content in some starches and glycogens. J Biochem 59:290–294
Takahata Y, Hoaki T, Maruyama T (2001) Starvation survivability of Thermococcus strains isolated from Japanese oil reservoirs. Arch Microbiol 176:264–270
Takata H, Takaha T, Okada S, Takagi M, Imanaka T (1997) Characterization of a gene cluster for glycogen biosynthesis and a heterotetrameric ADP-glucose pyrophosphorylase from Bacillus stearothermophilus. J Bacteriol 179:4689–4698
Takata H, Takaha T, Okada S, Takagi M, Imanaka T (1998) Purification and characterization of alpha-glucan phosphorylase from Bacillus stearothermophilus. J Ferment Bioeng 85:156–161
Tewari YB, Goldberg RN (1989) Thermodynamics of hydrolysis of disaccharides. Cellobiose, gentiobiose, isomaltose, and maltose. J Biol Chem 264:3966–3971
Tsintzas K, Williams C (1998) Human muscle glycogen metabolism during exercise. Effect of carbohydrate supplementation. Sports Med 25:7–23
Wallace RJ (1980) Cytoplasmic reserve polysaccharide of Selenomonas ruminantium. Appl Environ Microbiol 39:630–634
Waltermann M, Steinbuchel A (2005) Neutral lipid bodies in prokaryotes: recent insights into structure, formation, and relationship to eukaryotic lipid depots. J Bacteriol 187:3607–3619
Walther BA, Ewald PW (2004) Pathogen survival in the external environment and the evolution of virulence. Biol Rev Camb Philos Soc 79:849–869
Weber M, Wober G (1975) The fine structure of the branched alpha-D-glucan from the blue-green alga Anacystis nidulans: comparison with other bacterial glycogens and phytoglycogen. Carbohydr Res 39:295–302
Whyte JN, Strasdin GA (1972) An intracellular alpha-D-glucan from Clostridium botulinum, type E. Carbohydr Res 25:435–441
Wilkinson JF (1963) Carbon and energy storage in bacteria. J Gen Microbiol 32:171–176
Wilson WA, Roach PJ, Montero M, Baroja-Fernandez E, Munoz FJ, Eydallin G, Viale AM, Pozueta-Romero J (2010) Regulation of glycogen metabolism in yeast and bacteria. FEMS Microbiol Rev 34:952–958
Wolfrom ML, Lassettre EN, Oneill AN (1951) Degradation of glycogen to isomaltose. J Am Chem Soc 73:595–599
Yang XR, Miller MA, Yang R, Evans DF, Edstrom RD (1990) Scanning tunneling microscopic images show a laminated structure for glycogen molecules. FASEB J 4:3140–3143
Yoo SH, Keppel C, Spalding M, Jane JL (2007) Effects of growth condition on the structure of glycogen produced in cyanobacterium Synechocystis sp PCC6803. Int J Biol Macromol 40:498–504
Young FG (1957) Claude Bernard and the discovery of glycogen: a century of retrospect. Br Med J 1:1431–1437
Zevenhuizen LP (1992) Levels of trehalose and glycogen in Arthrobacter globiformis under conditions of nutrient starvation and osmotic stress. Antonie Leeuwenhoek 61:61–68
Zevenhuizen LP, Ebbink AG (1974) Interrelations between glycogen, poly-beta-hydroxybutyric acid and lipids during accumulation and subsequent utilization in a Pseudomonas. Antonie Leeuwenhoek 40:103–120
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Wang, L., Wise, M.J. Glycogen with short average chain length enhances bacterial durability. Naturwissenschaften 98, 719 (2011). https://doi.org/10.1007/s00114-011-0832-x
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DOI: https://doi.org/10.1007/s00114-011-0832-x