Structure of Streptomyces Maltosyltransferase GlgE, a Homologue of a Genetically Validated Anti-tuberculosis Target

Syson, Karl; Stevenson, Clare E. M.; Rejzek, Martin; Fairhurst, Shirley A.; Nair, A.; Bruton, Celia J.; Field, Robert A.; Chater, Keith F.; Lawson, David M.; Bornemann, Stephen

doi:10.1074/jbc.m111.279315

Cited by 58 publications

(152 citation statements)

References 49 publications

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“…Although the equilibrium of purified TreS favors the formation of trehalose from maltose in vitro, flux through TreS in vivo is in the opposite direction (24), which is driven by the rapid and irreversible ATP-dependent phosphorylation of the formed maltose to maltose-1-phosphate by the maltose kinase Pep2 (Rv0127) (26,27). The observed finding of the direction of flux through TreS for consumption of trehalose in M. smegmatis contradicts a previous study (9).…”

Section: Trehalose De Novo Biosynthesiscontrasting

confidence: 57%

Genetics of Mycobacterial Trehalose Metabolism

Kalscheuer

Koliwer‐Brandl

2014

Microbiol Spectr

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Trehalose [alpha-D-glucopyranosyl-(1→1)-alpha- D-glucopyranoside] is a highly abundant disaccharide in mycobacteria that fulfills many biological roles and has a plethora of possible metabolic fates. Trehalose is synthesized in mycobacteria de novo either from glycolytic intermediates or from alpha-glucans via two alternative routes, the OtsA-OtsB and the TreY-TreZ pathways, respectively. Intracellular trehalose can serve as an endogenous remobilizable carbon storage compound and as a biocompatible stress protectant. Furthermore, trehalose functions as the sugar core of many glycolipids with important structural or immunomodulatory functions such as the cord factor trehalose dimycolate, sulfolipids, and polyacyltrehalose. Moreover, trehalose plays a central role in the formation of the mycolic acid cell wall layer because it serves as a carrier molecule that shuttles mycolic acids in the form of the glycolipid trehalose monomycolate between the cytoplasm and the periplasm. In this process, a specific importer recycles the free trehalose that is extracellularly released as a by-product during mycolate processing via the antigen 85 complex, which might represent a specific adaptation to the intracellular lifestyle of Mycobacterium tuberculosis with limited carbohydrate availability. Finally, trehalose is converted to glycogen-like branched alpha-glucans by a four-step metabolic pathway involving the essential maltosyltransferase GlgE, which may be further processed to derivatives with intracellular or extracellular destinations such as polymethylated lipopolysaccharides or capsular alpha-glucans, respectively. In this article we summarize the current knowledge of the genetic basis of trehalose biosynthesis and metabolism in mycobacteria, the biological functions of trehalose-based molecules, and their roles in virulence of the human pathogen M. tuberculosis.

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Section: Trehalose De Novo Biosynthesiscontrasting

confidence: 57%

Genetics of Mycobacterial Trehalose Metabolism

Kalscheuer

Koliwer‐Brandl

2014

Microbiol Spectr

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“…2). Circular dichroism spectroscopy indicated that the net secondary structure of GlgE was not significantly affected by phosphorylation (supplemental Table S3) and was consistent with the known crystal structure of the S. coelicolor isoform I enzyme (31). It was then possible to determine the kinetics of the maltosyltransferase activity of GlgE and GlgE-P by monitoring the release of inor- FIGURE 2.…”

Section: Glge Is Phosphorylated In Vitro By the Mycobacterial Ser/thrmentioning

confidence: 99%

Mycobacterium tuberculosis Maltosyltransferase GlgE, a Genetically Validated Antituberculosis Target, Is Negatively Regulated by Ser/Thr Phosphorylation

Leiba

Syson

Baronian

et al. 2013

Journal of Biological Chemistry

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GlgE is a maltosyltransferase involved in the biosynthesis of α-glucans that has been genetically validated as a potential therapeutic target against Mycobacterium tuberculosis. Despite also making α-glucan, the GlgC/GlgA glycogen pathway is distinct and allosterically regulated. We have used a combination of genetics and biochemistry to establish how the GlgE pathway is regulated. M. tuberculosis GlgE was phosphorylated specifically by the Ser/Thr protein kinase PknB in vitro on one serine and six threonine residues. Furthermore, GlgE was phosphorylated in vivo when expressed in Mycobacterium bovis bacillus Calmette–Guérin (BCG) but not when all seven phosphorylation sites were replaced by Ala residues. The GlgE orthologues from Mycobacterium smegmatis and Streptomyces coelicolor were phosphorylated by the corresponding PknB orthologues in vitro, implying that the phosphorylation of GlgE is widespread among actinomycetes. PknB-dependent phosphorylation of GlgE led to a 2 orders of magnitude reduction in catalytic efficiency in vitro. The activities of phosphoablative and phosphomimetic GlgE derivatives, where each phosphorylation site was substituted with either Ala or Asp residues, respectively, correlated with negative phosphoregulation. Complementation studies of a M. smegmatis glgE mutant strain with these GlgE derivatives, together with both classical and chemical forward genetics, were consistent with flux through the GlgE pathway being correlated with GlgE activity. We conclude that the GlgE pathway appears to be negatively regulated in actinomycetes through the phosphorylation of GlgE by PknB, a mechanism distinct from that known in the classical glycogen pathway. Thus, these findings open new opportunities to target the GlgE pathway therapeutically.

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“…Furthermore, it is absent in humans, but is present in almost all mycobacteria and other opportunistic pathogens like Pseudomonas and Burkholderia species. The structure of its homologue from Streptomyces coelicolor was released only in 2011 and was reported to have similar catalytic properties with MtbGlgEtogether with a conserved active site 7 . With an available structure of the drug target, structurebased drug design may now be employed.…”

Section: Oriental Journal Of Chemistrymentioning

confidence: 99%

Structure-Based Design of Inhibitors Against Maltosyltransferase Glge

Billones¹

2014

Orient. J. Chem

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The emergence ofMycobacterium tuberculosis(Mtb) drug resistant strains calls for research of novel anti-TB drugs. In this study,structure-based pharmacophore generation, virtual screening, molecular docking and de novolead optimization were employed in the search for possible inhibitors of MaltosyltransferaseGlgE enzyme,a recently validated anti-TB drug target. Chemical libraries containing only natural productswere screened. The top hits were docked and the resulting leads were subsequently modified usingDe Novo Evolution. Three modified compounds were found to have greaterbinding energy than the substrate. All were derived from the lead compound ZINC39010596 (5,7-dihydroxy-2-propan-2-yl-8-[(2S,3R,4S,5S,6R)-3,4,5-trihydroxy-6-(hydroxymethyl)tetrahydro-2H-pyran-2-yl]oxychromen-4-one). Toxicity predictions of these compounds revealed that they are non-carcinogenic, non-mutagenic, and biodegradable.

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Structure of Streptomyces Maltosyltransferase GlgE, a Homologue of a Genetically Validated Anti-tuberculosis Target

Cited by 58 publications

References 49 publications

Genetics of Mycobacterial Trehalose Metabolism

Genetics of Mycobacterial Trehalose Metabolism

Mycobacterium tuberculosis Maltosyltransferase GlgE, a Genetically Validated Antituberculosis Target, Is Negatively Regulated by Ser/Thr Phosphorylation

Structure-Based Design of Inhibitors Against Maltosyltransferase Glge

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