Recycling of the Anhydro-
            <i>N</i>
            -Acetylmuramic Acid Derived from Cell Wall Murein Involves a Two-Step Conversion to
            <i>N</i>
            -Acetylglucosamine-Phosphate

Uehara, Tsuyoshi; Suefuji, Kyoko; Valbuena, Noelia; Meehan, Brian; Donegan, Michael; Park, James T.

doi:10.1128/jb.187.11.3643-3649.2005

Cited by 85 publications

(97 citation statements)

References 27 publications

(40 reference statements)

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“…The muropeptides generated in the cytoplasm through the activities of NagZ, AmpD and LdcA rejoin the biosynthesis pathway through the sequential activity of AnmK, MurQ, NagA and NagB in E. coli [168][169][170][171] (Figs 1 and 2).…”

Section: Convergence Of Recycling and Biosynthesismentioning

confidence: 99%

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Cell-wall recycling and synthesis in Escherichia coli and Pseudomonas aeruginosa – their role in the development of resistance

Dhar

Kumari

Balasubramanian

et al. 2018

Journal of Medical Microbiology

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The bacterial cell-wall that forms a protective layer over the inner membrane is called the murein sacculus -a tightly crosslinked peptidoglycan mesh unique to bacteria. Cell-wall synthesis and recycling are critical cellular processes essential for cell growth, elongation and division. Both de novo synthesis and recycling involve an array of enzymes across all cellular compartments, namely the outer membrane, periplasm, inner membrane and cytoplasm. Due to the exclusivity of peptidoglycan in the bacterial cell-wall, these players are the target of choice for many antibacterial agents. Our current understanding of cell-wall biochemistry and biogenesis in Gram-negative organisms stems mostly from studies of Escherichia coli. An incomplete knowledge on these processes exists for the opportunistic Gram-negative pathogen, Pseudomonas aeruginosa. In this review, cell-wall synthesis and recycling in the various cellular compartments are compared and contrasted between E. coli and P. aeruginosa. Despite the fact that there is a remarkable similarity of these processes between the two bacterial species, crucial differences alter their resistance to b-lactams, fluoroquinolones and aminoglycosides. One of the common mediators underlying resistance is the amp system whose mechanism of action is closely associated with the cell-wall recycling pathway. The activation of amp genes results in expression of AmpC blactamase through its cognate regulator AmpR which further regulates multi-drug resistance. In addition, other cell-wall recycling enzymes also contribute to antibiotic resistance. This comprehensive summary of the information should spawn new ideas on how to effectively target cell-wall processes to combat the growing resistance to existing antibiotics.

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Section: Convergence Of Recycling and Biosynthesismentioning

confidence: 99%

“…In E. coli, AnmK kinase phosphorylates anhMurNAc to MurNAc-6-P which is processed by MurQ etherase to form GlcNAc-6-P [168]. GlcNAc generated in the cytoplasm after the NagZ activity is phosphorylated to GlcNAc-6-P by NagK [172].…”

Section: Convergence Of Recycling and Biosynthesismentioning

confidence: 99%

Cell-wall recycling and synthesis in Escherichia coli and Pseudomonas aeruginosa – their role in the development of resistance

Dhar

Kumari

Balasubramanian

et al. 2018

Journal of Medical Microbiology

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“…In the AnmK family, the function of AnmK was approved by experiments in E. coli (Uehara et al 2005), whereas LGK-like proteins in fungi were hypothetical LGK-like proteins from fungi and AnmK from E. coli MG1655. The phylogenetic relationship was analyzed by the ClutalX2.03 (Thompson et al 1997) proteins.…”

Section: Comparison and Alignment Of Amino Acid Sequencesmentioning

confidence: 99%

Cloning of a novel levoglucosan kinase gene from Lipomyces starkeyi and its expression in Escherichia coli

Dai

et al. 2009

World J Microbiol Biotechnol

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Levoglucosan, cellulosic pyrolysate, is converted to glucose-6-phosphate by a specific levoglucosan kinase in fungi. A novel cDNA of levoglucosan kinase gene (lgk) from yeast Lipomyces starkeyi YZ-215 was isolated by RACE method. The 1,445 bp cDNA fragment (lgk) harbouring the kinase gene exhibited one open reading frame (ORF) composed of 1,317 bp flanked by a 14 bp 5 0 -UTR and a 114 bp 3 0 -UTR, including a 25 bp poly(A) tail. The ORF encoded a 439 amino acid polypeptide with a 48.4 kDa predicted molecular mass. Analysis of amino sequence revealed that the kinase belonged to the bacterial anhydro-N-acetylmuramic acid kinase (AnmK) family, and kinase-like proteins existed in some fungi, especially in filamentous fungi such as Aspergillus. The kinase gene was transformed into Escherichia coli BL21 (DE3), recombinant E. coli could grow in M9 minimal medium with levoglucosan as a sole carbon source when induced by IPTG. In addition, the recombinant kinase was overexpressed, purified and characterized. The kinase was stable at pH 7-10 and showed maximum activity at 30°C and pH 9.0 as natural kinase, but presented higher thermostability. Kinetic constants (apparent K m values) for LG and ATP were 105.3 ± 12.5 and 0.20 ± 0.02 mM, respectively. Furthermore, the kinase showed substrate specificity for LG. This novel levoglucosan kinase gene would be useful in constructing recombinant microbial strains for the efficient bioconversion of cellulosic pyrolysate to ethanol.

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“…The catalytic constants for the Zn-and Cd-substituted forms of NagA support the conclusion that the carbonyl group of the substrate is polarized by a direct interaction with the single divalent cation bound to the M β -position in the active site. (2) and N-formyl-D-glucosamine-6-phosphate (5). The kinetic constants for NagA with these substrate analogs are listed in Table 2 The N-trifluoroacetyl substituted substrate is hydrolyzed 26 times faster than the natural substrate but the N -formyl substrate is hydrolyze more slowly by a factor of 5.…”

Section: Substrate Specificitymentioning

confidence: 99%

N-Acetyl-d-glucosamine-6-phosphate Deacetylase: Substrate Activation via a Single Divalent Metal Ion

Hall

Xiang

et al. 2007

Biochemistry

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NagA is a member of the amidohydrolase superfamily and catalyzes the deacetylation of N-acetyl-D-glucosamine-6-phosphate. The catalytic mechanism of this enzyme was addressed by the characterization of the catalytic properties of metal-substituted derivatives of NagA from Escherichia coli with a variety of substrate analogs. The reaction mechanism is of interest since NagA from bacterial sources is found with either one or two divalent metal ions in the active site. This observation indicates that there has been a divergence in the evolution of NagA and suggests that there are fundamental differences in the mechanistic details for substrate activation and hydrolysis. NagA from E. coli was inactivated by the removal of the zinc bound to the active site and the apo-enzyme reactivated upon incubation with one equivalent of Zn 2+ , Cd 2+ , Co 2+ , Mn 2+ , Ni 2+ or Fe 2+ . In the proposed catalytic mechanism the reaction is initiated by the polarization of the carbonyl group of the substrate via a direct interaction with the divalent metal ion and His-143. The invariant aspartate found at the end of β-strand 8 in all members of the amidohydrolase superfamily abstracts a proton from the metal-bound water molecule (or hydroxide) to promote the hydrolytic attack on the carbonyl group of the substrate. A tetrahedral intermediate is formed and then collapses with cleavage of the C-N bond after proton transfer to the leaving group amine by Asp-273. The lack of a solvent isotope effect by D 2 O and the absence of any changes to the kinetic constants with increases in solvent viscosity indicate that net product formation is not limited to any significant extent by proton transfer steps or the release of products. N-trifluoroacetyl-D-glucosamine-6-phosphate is hydrolyzed by NagA 26-fold faster than the corresponding N-acetyl derivative. This result is consistent with the formation or collapse of the tetrahedral intermediate as the rate limiting step in the catalytic mechanism of NagA.NagA 1 catalyzes the hydrolytic cleavage of N-acetyl-D-glucosamine-6-phosphate as illustrated in Scheme 1. The deacetylation of this compound provides a source of carbon and nitrogen by preparing this substrate for entry into the glycolytic pathway. This reaction is a key step in the catabolism of N-acetyl-D-glucosamine, derived from the degradation of chitin, and is an essential component for the biosynthesis of lipopolysaccharides and peptidoglycans. More recently, the reaction catalyzed by NagA has been shown to be an important step in the recycling of cell wall murein (1-3).The purification of NagA from Escherichia coli was originally reported by White and Pasternak (4). The enzyme oligomerizes as a tetramer and each subunit contains a reactive sulfhydryl group near the active site (5). In the forward reaction, inhibition occurs at high substrate † This work was supported in part by the NIH (GM 71790) and the Robert A. Welch Foundation (A-840). RSH was supported by a Chemical Biology Interface Training Grant (GM 08523). * To whom cor...

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Recycling of the Anhydro- N -Acetylmuramic Acid Derived from Cell Wall Murein Involves a Two-Step Conversion to N -Acetylglucosamine-Phosphate

Cited by 85 publications

References 27 publications

Cell-wall recycling and synthesis in Escherichia coli and Pseudomonas aeruginosa – their role in the development of resistance

Cell-wall recycling and synthesis in Escherichia coli and Pseudomonas aeruginosa – their role in the development of resistance

Cloning of a novel levoglucosan kinase gene from Lipomyces starkeyi and its expression in Escherichia coli

N-Acetyl-d-glucosamine-6-phosphate Deacetylase: Substrate Activation via a Single Divalent Metal Ion

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