UDP-N-acetylmuramic Acid

14,000,000 Leading Edge Experts on the ideXlab platform

Scan Science and Technology

Contact Leading Edge Experts & Companies

Scan Science and Technology

Contact Leading Edge Experts & Companies

The Experts below are selected from a list of 713682 Experts worldwide ranked by ideXlab platform

Didier Blanot - One of the best experts on this subject based on the ideXlab platform.

  • synthetic tripeptides as alternate substrates of murein peptide ligase mpl
    Biochimie, 2013
    Co-Authors: Mireille Herve, Cecile Cardoso, Boris Brus, Hélène Barreteau, Delphine Patin, Andreja Kovac, Stanislav Gobec, Dominique Menginlecreulx, Didier Blanot
    Abstract:

    Abstract Murein peptide ligase (Mpl) is an enzyme found in Gram-negative bacteria. It catalyses the addition of tripeptide l -Ala-γ- d -Glu-meso-diaminopimelate to nucleotide precursor UDP-N-acetylmuramic Acid during the recycling of peptidoglycan. Although not essential, this enzyme represents an interesting target for antibacterial compounds through the synthesis of alternate substrates whose incorporation into peptidoglycan might be deleterious for the bacterial cell. Therefore, we have synthesised 10 tripeptides l -Ala-γ- d -Glu-Xaa in which Xaa represents amino Acids different from diaminopimelic Acid. Tripeptide with Xaa = e- d -Lys proved to be an excellent substrate of Escherichia coli Mpl in vitro. Tripeptides with Xaa = p-amino- or p-nitro- l -phenylalanine were poor substrates, while tripeptides with Xaa =  d- or l -2-aminopimelate, dl -2-aminoheptanoic Acid, l -Glu, l -norleucine, l -norvaline, l -2-aminobutyric Acid or l -Ala were not substrates at all. Although a good Mpl substrate, the d -Lys-containing tripeptide was devoid of antibacterial activity against E. coli, presumably owing to poor uptake.

  • synthetic tripeptides as alternate substrates of murein peptide ligase mpl
    Biochimie, 2013
    Co-Authors: Mireille Herve, Cecile Cardoso, Boris Brus, Hélène Barreteau, Delphine Patin, Andreja Kovac, Stanislav Gobec, Dominique Menginlecreulx, Didier Blanot
    Abstract:

    Abstract Murein peptide ligase (Mpl) is an enzyme found in Gram-negative bacteria. It catalyses the addition of tripeptide l -Ala-γ- d -Glu-meso-diaminopimelate to nucleotide precursor UDP-N-acetylmuramic Acid during the recycling of peptidoglycan. Although not essential, this enzyme represents an interesting target for antibacterial compounds through the synthesis of alternate substrates whose incorporation into peptidoglycan might be deleterious for the bacterial cell. Therefore, we have synthesised 10 tripeptides l -Ala-γ- d -Glu-Xaa in which Xaa represents amino Acids different from diaminopimelic Acid. Tripeptide with Xaa = e- d -Lys proved to be an excellent substrate of Escherichia coli Mpl in vitro. Tripeptides with Xaa = p-amino- or p-nitro- l -phenylalanine were poor substrates, while tripeptides with Xaa =  d- or l -2-aminopimelate, dl -2-aminoheptanoic Acid, l -Glu, l -norleucine, l -norvaline, l -2-aminobutyric Acid or l -Ala were not substrates at all. Although a good Mpl substrate, the d -Lys-containing tripeptide was devoid of antibacterial activity against E. coli, presumably owing to poor uptake.

  • phosphorylated hydroxyethylamines as novel inhibitors of the bacterial cell wall biosynthesis enzymes murc to murf
    Bioorganic Chemistry, 2009
    Co-Authors: Matej Sova, Didier Blanot, Andreja Kovac, Samo Turk, Martina Hrast, Stanislav Gobec
    Abstract:

    Abstract Enzymes involved in the biosynthesis of bacterial peptidoglycan represent important targets for development of new antibacterial drugs. Among them, Mur ligases (MurC to MurF) catalyze the formation of the final cytoplasmic precursor UDP-N-acetylmuramyl-pentapeptide from UDP-N-acetylmuramic Acid. We present the design, synthesis and biological evaluation of a series of phosphorylated hydroxyethylamines as new type of small-molecule inhibitors of Mur ligases. We show that the phosphate group attached to the hydroxyl moiety of the hydroxyethylamine core is essential for good inhibitory activity. The IC50 values of these inhibitors were in the micromolar range, which makes them a promising starting point for the development of multiple inhibitors of Mur ligases as potential antibacterial agents. In addition, 1-(4-methoxyphenylsulfonamido)-3-morpholinopropan-2-yl dihydrogen phosphate 7a was discovered as one of the best inhibitors of MurE described so far.

  • cytoplasmic steps of peptidoglycan biosynthesis
    Fems Microbiology Reviews, 2008
    Co-Authors: Hélène Barreteau, Andreja Kovac, Stanislav Gobec, Audrey Boniface, Matej Sova, Didier Blanot
    Abstract:

    The biosynthesis of bacterial cell wall peptidoglycan is a complex process that involves enzyme reactions that take place in the cytoplasm (synthesis of the nucleotide precursors) and on the inner side (synthesis of lipid-linked intermediates) and outer side (polymerization reactions) of the cytoplasmic membrane. This review deals with the cytoplasmic steps of peptidoglycan biosynthesis, which can be divided into four sets of reactions that lead to the syntheses of (1) UDP-N-acetylglucosamine from fructose 6-phosphate, (2) UDP-N-acetylmuramic Acid from UDP-N-acetylglucosamine, (3) UDP-N-acetylmuramyl-pentapeptide from UDP-N-acetylmuramic Acid and (4) D-glutamic Acid and dipeptide D-alanyl-D-alanine. Recent data concerning the different enzymes involved are presented. Moreover, special attention is given to (1) the chemical and enzymatic synthesis of the nucleotide precursor substrates that are not commercially available and (2) the search for specific inhibitors that could act as antibacterial compounds.

Mireille Herve - One of the best experts on this subject based on the ideXlab platform.

  • synthetic tripeptides as alternate substrates of murein peptide ligase mpl
    Biochimie, 2013
    Co-Authors: Mireille Herve, Cecile Cardoso, Boris Brus, Hélène Barreteau, Delphine Patin, Andreja Kovac, Stanislav Gobec, Dominique Menginlecreulx, Didier Blanot
    Abstract:

    Abstract Murein peptide ligase (Mpl) is an enzyme found in Gram-negative bacteria. It catalyses the addition of tripeptide l -Ala-γ- d -Glu-meso-diaminopimelate to nucleotide precursor UDP-N-acetylmuramic Acid during the recycling of peptidoglycan. Although not essential, this enzyme represents an interesting target for antibacterial compounds through the synthesis of alternate substrates whose incorporation into peptidoglycan might be deleterious for the bacterial cell. Therefore, we have synthesised 10 tripeptides l -Ala-γ- d -Glu-Xaa in which Xaa represents amino Acids different from diaminopimelic Acid. Tripeptide with Xaa = e- d -Lys proved to be an excellent substrate of Escherichia coli Mpl in vitro. Tripeptides with Xaa = p-amino- or p-nitro- l -phenylalanine were poor substrates, while tripeptides with Xaa =  d- or l -2-aminopimelate, dl -2-aminoheptanoic Acid, l -Glu, l -norleucine, l -norvaline, l -2-aminobutyric Acid or l -Ala were not substrates at all. Although a good Mpl substrate, the d -Lys-containing tripeptide was devoid of antibacterial activity against E. coli, presumably owing to poor uptake.

  • synthetic tripeptides as alternate substrates of murein peptide ligase mpl
    Biochimie, 2013
    Co-Authors: Mireille Herve, Cecile Cardoso, Boris Brus, Hélène Barreteau, Delphine Patin, Andreja Kovac, Stanislav Gobec, Dominique Menginlecreulx, Didier Blanot
    Abstract:

    Abstract Murein peptide ligase (Mpl) is an enzyme found in Gram-negative bacteria. It catalyses the addition of tripeptide l -Ala-γ- d -Glu-meso-diaminopimelate to nucleotide precursor UDP-N-acetylmuramic Acid during the recycling of peptidoglycan. Although not essential, this enzyme represents an interesting target for antibacterial compounds through the synthesis of alternate substrates whose incorporation into peptidoglycan might be deleterious for the bacterial cell. Therefore, we have synthesised 10 tripeptides l -Ala-γ- d -Glu-Xaa in which Xaa represents amino Acids different from diaminopimelic Acid. Tripeptide with Xaa = e- d -Lys proved to be an excellent substrate of Escherichia coli Mpl in vitro. Tripeptides with Xaa = p-amino- or p-nitro- l -phenylalanine were poor substrates, while tripeptides with Xaa =  d- or l -2-aminopimelate, dl -2-aminoheptanoic Acid, l -Glu, l -norleucine, l -norvaline, l -2-aminobutyric Acid or l -Ala were not substrates at all. Although a good Mpl substrate, the d -Lys-containing tripeptide was devoid of antibacterial activity against E. coli, presumably owing to poor uptake.

  • structure and function of the first full length murein peptide ligase mpl cell wall recycling protein
    PLOS ONE, 2011
    Co-Authors: Debanu Das, Mireille Herve, Julie Feuerhelm, Carol L Farr, Hsiuju Chiu, Marcandre Elsliger, Mark W Knuth, Heath E Klock, Mitchell D Miller
    Abstract:

    Bacterial cell walls contain peptidoglycan, an essential polymer made by enzymes in the Mur pathway. These proteins are specific to bacteria, which make them targets for drug discovery. MurC, MurD, MurE and MurF catalyze the synthesis of the peptidoglycan precursor UDP-N-acetylmuramoyl-L-alanyl-γ-D-glutamyl-meso-diaminopimelyl-D-alanyl-D-alanine by the sequential addition of amino Acids onto UDP-N-acetylmuramic Acid (UDP-MurNAc). MurC-F enzymes have been extensively studied by biochemistry and X-ray crystallography. In Gram-negative bacteria, ∼30–60% of the bacterial cell wall is recycled during each generation. Part of this recycling process involves the murein peptide ligase (Mpl), which attaches the breakdown product, the tripeptide L-alanyl-γ-D-glutamyl-meso-diaminopimelate, to UDP-MurNAc. We present the crystal structure at 1.65 A resolution of a full-length Mpl from the permafrost bacterium Psychrobacter arcticus 273-4 (PaMpl). Although the Mpl structure has similarities to Mur enzymes, it has unique sequence and structure features that are likely related to its role in cell wall recycling, a function that differentiates it from the MurC-F enzymes. We have analyzed the sequence-structure relationships that are unique to Mpl proteins and compared them to MurC-F ligases. We have also characterized the biochemical properties of this enzyme (optimal temperature, pH and magnesium binding profiles and kinetic parameters). Although the structure does not contain any bound substrates, we have identified ∼30 residues that are likely to be important for recognition of the tripeptide and UDP-MurNAc substrates, as well as features that are unique to Psychrobacter Mpl proteins. These results provide the basis for future mutational studies for more extensive function characterization of the Mpl sequence-structure relationships.

Stanislav Gobec - One of the best experts on this subject based on the ideXlab platform.

  • synthetic tripeptides as alternate substrates of murein peptide ligase mpl
    Biochimie, 2013
    Co-Authors: Mireille Herve, Cecile Cardoso, Boris Brus, Hélène Barreteau, Delphine Patin, Andreja Kovac, Stanislav Gobec, Dominique Menginlecreulx, Didier Blanot
    Abstract:

    Abstract Murein peptide ligase (Mpl) is an enzyme found in Gram-negative bacteria. It catalyses the addition of tripeptide l -Ala-γ- d -Glu-meso-diaminopimelate to nucleotide precursor UDP-N-acetylmuramic Acid during the recycling of peptidoglycan. Although not essential, this enzyme represents an interesting target for antibacterial compounds through the synthesis of alternate substrates whose incorporation into peptidoglycan might be deleterious for the bacterial cell. Therefore, we have synthesised 10 tripeptides l -Ala-γ- d -Glu-Xaa in which Xaa represents amino Acids different from diaminopimelic Acid. Tripeptide with Xaa = e- d -Lys proved to be an excellent substrate of Escherichia coli Mpl in vitro. Tripeptides with Xaa = p-amino- or p-nitro- l -phenylalanine were poor substrates, while tripeptides with Xaa =  d- or l -2-aminopimelate, dl -2-aminoheptanoic Acid, l -Glu, l -norleucine, l -norvaline, l -2-aminobutyric Acid or l -Ala were not substrates at all. Although a good Mpl substrate, the d -Lys-containing tripeptide was devoid of antibacterial activity against E. coli, presumably owing to poor uptake.

  • synthetic tripeptides as alternate substrates of murein peptide ligase mpl
    Biochimie, 2013
    Co-Authors: Mireille Herve, Cecile Cardoso, Boris Brus, Hélène Barreteau, Delphine Patin, Andreja Kovac, Stanislav Gobec, Dominique Menginlecreulx, Didier Blanot
    Abstract:

    Abstract Murein peptide ligase (Mpl) is an enzyme found in Gram-negative bacteria. It catalyses the addition of tripeptide l -Ala-γ- d -Glu-meso-diaminopimelate to nucleotide precursor UDP-N-acetylmuramic Acid during the recycling of peptidoglycan. Although not essential, this enzyme represents an interesting target for antibacterial compounds through the synthesis of alternate substrates whose incorporation into peptidoglycan might be deleterious for the bacterial cell. Therefore, we have synthesised 10 tripeptides l -Ala-γ- d -Glu-Xaa in which Xaa represents amino Acids different from diaminopimelic Acid. Tripeptide with Xaa = e- d -Lys proved to be an excellent substrate of Escherichia coli Mpl in vitro. Tripeptides with Xaa = p-amino- or p-nitro- l -phenylalanine were poor substrates, while tripeptides with Xaa =  d- or l -2-aminopimelate, dl -2-aminoheptanoic Acid, l -Glu, l -norleucine, l -norvaline, l -2-aminobutyric Acid or l -Ala were not substrates at all. Although a good Mpl substrate, the d -Lys-containing tripeptide was devoid of antibacterial activity against E. coli, presumably owing to poor uptake.

  • phosphorylated hydroxyethylamines as novel inhibitors of the bacterial cell wall biosynthesis enzymes murc to murf
    Bioorganic Chemistry, 2009
    Co-Authors: Matej Sova, Didier Blanot, Andreja Kovac, Samo Turk, Martina Hrast, Stanislav Gobec
    Abstract:

    Abstract Enzymes involved in the biosynthesis of bacterial peptidoglycan represent important targets for development of new antibacterial drugs. Among them, Mur ligases (MurC to MurF) catalyze the formation of the final cytoplasmic precursor UDP-N-acetylmuramyl-pentapeptide from UDP-N-acetylmuramic Acid. We present the design, synthesis and biological evaluation of a series of phosphorylated hydroxyethylamines as new type of small-molecule inhibitors of Mur ligases. We show that the phosphate group attached to the hydroxyl moiety of the hydroxyethylamine core is essential for good inhibitory activity. The IC50 values of these inhibitors were in the micromolar range, which makes them a promising starting point for the development of multiple inhibitors of Mur ligases as potential antibacterial agents. In addition, 1-(4-methoxyphenylsulfonamido)-3-morpholinopropan-2-yl dihydrogen phosphate 7a was discovered as one of the best inhibitors of MurE described so far.

  • cytoplasmic steps of peptidoglycan biosynthesis
    Fems Microbiology Reviews, 2008
    Co-Authors: Hélène Barreteau, Andreja Kovac, Stanislav Gobec, Audrey Boniface, Matej Sova, Didier Blanot
    Abstract:

    The biosynthesis of bacterial cell wall peptidoglycan is a complex process that involves enzyme reactions that take place in the cytoplasm (synthesis of the nucleotide precursors) and on the inner side (synthesis of lipid-linked intermediates) and outer side (polymerization reactions) of the cytoplasmic membrane. This review deals with the cytoplasmic steps of peptidoglycan biosynthesis, which can be divided into four sets of reactions that lead to the syntheses of (1) UDP-N-acetylglucosamine from fructose 6-phosphate, (2) UDP-N-acetylmuramic Acid from UDP-N-acetylglucosamine, (3) UDP-N-acetylmuramyl-pentapeptide from UDP-N-acetylmuramic Acid and (4) D-glutamic Acid and dipeptide D-alanyl-D-alanine. Recent data concerning the different enzymes involved are presented. Moreover, special attention is given to (1) the chemical and enzymatic synthesis of the nucleotide precursor substrates that are not commercially available and (2) the search for specific inhibitors that could act as antibacterial compounds.

Andreja Kovac - One of the best experts on this subject based on the ideXlab platform.

  • synthetic tripeptides as alternate substrates of murein peptide ligase mpl
    Biochimie, 2013
    Co-Authors: Mireille Herve, Cecile Cardoso, Boris Brus, Hélène Barreteau, Delphine Patin, Andreja Kovac, Stanislav Gobec, Dominique Menginlecreulx, Didier Blanot
    Abstract:

    Abstract Murein peptide ligase (Mpl) is an enzyme found in Gram-negative bacteria. It catalyses the addition of tripeptide l -Ala-γ- d -Glu-meso-diaminopimelate to nucleotide precursor UDP-N-acetylmuramic Acid during the recycling of peptidoglycan. Although not essential, this enzyme represents an interesting target for antibacterial compounds through the synthesis of alternate substrates whose incorporation into peptidoglycan might be deleterious for the bacterial cell. Therefore, we have synthesised 10 tripeptides l -Ala-γ- d -Glu-Xaa in which Xaa represents amino Acids different from diaminopimelic Acid. Tripeptide with Xaa = e- d -Lys proved to be an excellent substrate of Escherichia coli Mpl in vitro. Tripeptides with Xaa = p-amino- or p-nitro- l -phenylalanine were poor substrates, while tripeptides with Xaa =  d- or l -2-aminopimelate, dl -2-aminoheptanoic Acid, l -Glu, l -norleucine, l -norvaline, l -2-aminobutyric Acid or l -Ala were not substrates at all. Although a good Mpl substrate, the d -Lys-containing tripeptide was devoid of antibacterial activity against E. coli, presumably owing to poor uptake.

  • synthetic tripeptides as alternate substrates of murein peptide ligase mpl
    Biochimie, 2013
    Co-Authors: Mireille Herve, Cecile Cardoso, Boris Brus, Hélène Barreteau, Delphine Patin, Andreja Kovac, Stanislav Gobec, Dominique Menginlecreulx, Didier Blanot
    Abstract:

    Abstract Murein peptide ligase (Mpl) is an enzyme found in Gram-negative bacteria. It catalyses the addition of tripeptide l -Ala-γ- d -Glu-meso-diaminopimelate to nucleotide precursor UDP-N-acetylmuramic Acid during the recycling of peptidoglycan. Although not essential, this enzyme represents an interesting target for antibacterial compounds through the synthesis of alternate substrates whose incorporation into peptidoglycan might be deleterious for the bacterial cell. Therefore, we have synthesised 10 tripeptides l -Ala-γ- d -Glu-Xaa in which Xaa represents amino Acids different from diaminopimelic Acid. Tripeptide with Xaa = e- d -Lys proved to be an excellent substrate of Escherichia coli Mpl in vitro. Tripeptides with Xaa = p-amino- or p-nitro- l -phenylalanine were poor substrates, while tripeptides with Xaa =  d- or l -2-aminopimelate, dl -2-aminoheptanoic Acid, l -Glu, l -norleucine, l -norvaline, l -2-aminobutyric Acid or l -Ala were not substrates at all. Although a good Mpl substrate, the d -Lys-containing tripeptide was devoid of antibacterial activity against E. coli, presumably owing to poor uptake.

  • phosphorylated hydroxyethylamines as novel inhibitors of the bacterial cell wall biosynthesis enzymes murc to murf
    Bioorganic Chemistry, 2009
    Co-Authors: Matej Sova, Didier Blanot, Andreja Kovac, Samo Turk, Martina Hrast, Stanislav Gobec
    Abstract:

    Abstract Enzymes involved in the biosynthesis of bacterial peptidoglycan represent important targets for development of new antibacterial drugs. Among them, Mur ligases (MurC to MurF) catalyze the formation of the final cytoplasmic precursor UDP-N-acetylmuramyl-pentapeptide from UDP-N-acetylmuramic Acid. We present the design, synthesis and biological evaluation of a series of phosphorylated hydroxyethylamines as new type of small-molecule inhibitors of Mur ligases. We show that the phosphate group attached to the hydroxyl moiety of the hydroxyethylamine core is essential for good inhibitory activity. The IC50 values of these inhibitors were in the micromolar range, which makes them a promising starting point for the development of multiple inhibitors of Mur ligases as potential antibacterial agents. In addition, 1-(4-methoxyphenylsulfonamido)-3-morpholinopropan-2-yl dihydrogen phosphate 7a was discovered as one of the best inhibitors of MurE described so far.

  • cytoplasmic steps of peptidoglycan biosynthesis
    Fems Microbiology Reviews, 2008
    Co-Authors: Hélène Barreteau, Andreja Kovac, Stanislav Gobec, Audrey Boniface, Matej Sova, Didier Blanot
    Abstract:

    The biosynthesis of bacterial cell wall peptidoglycan is a complex process that involves enzyme reactions that take place in the cytoplasm (synthesis of the nucleotide precursors) and on the inner side (synthesis of lipid-linked intermediates) and outer side (polymerization reactions) of the cytoplasmic membrane. This review deals with the cytoplasmic steps of peptidoglycan biosynthesis, which can be divided into four sets of reactions that lead to the syntheses of (1) UDP-N-acetylglucosamine from fructose 6-phosphate, (2) UDP-N-acetylmuramic Acid from UDP-N-acetylglucosamine, (3) UDP-N-acetylmuramyl-pentapeptide from UDP-N-acetylmuramic Acid and (4) D-glutamic Acid and dipeptide D-alanyl-D-alanine. Recent data concerning the different enzymes involved are presented. Moreover, special attention is given to (1) the chemical and enzymatic synthesis of the nucleotide precursor substrates that are not commercially available and (2) the search for specific inhibitors that could act as antibacterial compounds.

Dominique Menginlecreulx - One of the best experts on this subject based on the ideXlab platform.

  • synthetic tripeptides as alternate substrates of murein peptide ligase mpl
    Biochimie, 2013
    Co-Authors: Mireille Herve, Cecile Cardoso, Boris Brus, Hélène Barreteau, Delphine Patin, Andreja Kovac, Stanislav Gobec, Dominique Menginlecreulx, Didier Blanot
    Abstract:

    Abstract Murein peptide ligase (Mpl) is an enzyme found in Gram-negative bacteria. It catalyses the addition of tripeptide l -Ala-γ- d -Glu-meso-diaminopimelate to nucleotide precursor UDP-N-acetylmuramic Acid during the recycling of peptidoglycan. Although not essential, this enzyme represents an interesting target for antibacterial compounds through the synthesis of alternate substrates whose incorporation into peptidoglycan might be deleterious for the bacterial cell. Therefore, we have synthesised 10 tripeptides l -Ala-γ- d -Glu-Xaa in which Xaa represents amino Acids different from diaminopimelic Acid. Tripeptide with Xaa = e- d -Lys proved to be an excellent substrate of Escherichia coli Mpl in vitro. Tripeptides with Xaa = p-amino- or p-nitro- l -phenylalanine were poor substrates, while tripeptides with Xaa =  d- or l -2-aminopimelate, dl -2-aminoheptanoic Acid, l -Glu, l -norleucine, l -norvaline, l -2-aminobutyric Acid or l -Ala were not substrates at all. Although a good Mpl substrate, the d -Lys-containing tripeptide was devoid of antibacterial activity against E. coli, presumably owing to poor uptake.

  • synthetic tripeptides as alternate substrates of murein peptide ligase mpl
    Biochimie, 2013
    Co-Authors: Mireille Herve, Cecile Cardoso, Boris Brus, Hélène Barreteau, Delphine Patin, Andreja Kovac, Stanislav Gobec, Dominique Menginlecreulx, Didier Blanot
    Abstract:

    Abstract Murein peptide ligase (Mpl) is an enzyme found in Gram-negative bacteria. It catalyses the addition of tripeptide l -Ala-γ- d -Glu-meso-diaminopimelate to nucleotide precursor UDP-N-acetylmuramic Acid during the recycling of peptidoglycan. Although not essential, this enzyme represents an interesting target for antibacterial compounds through the synthesis of alternate substrates whose incorporation into peptidoglycan might be deleterious for the bacterial cell. Therefore, we have synthesised 10 tripeptides l -Ala-γ- d -Glu-Xaa in which Xaa represents amino Acids different from diaminopimelic Acid. Tripeptide with Xaa = e- d -Lys proved to be an excellent substrate of Escherichia coli Mpl in vitro. Tripeptides with Xaa = p-amino- or p-nitro- l -phenylalanine were poor substrates, while tripeptides with Xaa =  d- or l -2-aminopimelate, dl -2-aminoheptanoic Acid, l -Glu, l -norleucine, l -norvaline, l -2-aminobutyric Acid or l -Ala were not substrates at all. Although a good Mpl substrate, the d -Lys-containing tripeptide was devoid of antibacterial activity against E. coli, presumably owing to poor uptake.

  • copurification of glucosamine 1 phosphate acetyltransferase and n acetylglucosamine 1 phosphate uridyltransferase activities of escherichia coli characterization of the glmu gene product as a bifunctional enzyme catalyzing two subsequent steps in the
    Journal of Bacteriology, 1994
    Co-Authors: Dominique Menginlecreulx, J Van Heijenoort
    Abstract:

    The glmU gene product of Escherichia coli was recently identified as the N-acetylglucosamine-1-phosphate uridyltransferase activity which catalyzes the formation of UDP-N-acetylglucosamine, an essential precursor for cell wall peptidoglycan and lipopolysaccharide biosyntheses (D. Mengin-Lecreulx and J. van Heijenoort, J. Bacteriol. 175:6150-6157, 1993). Evidence that the purified GlmU protein is in fact a bifunctional enzyme which also catalyzes acetylation of glucosamine-1-phosphate, the preceding step in the same pathway, is now provided. Kinetic parameters of both reactions were investigated, indicating in particular that the acetyltransferase activity of the enzyme is fivefold higher than its uridyltransferase activity. In contrast to the uridyltransferase activity, which is quite stable and insensitive to thiol reagents, the acetyltransferase activity was rapidly lost when the enzyme was stored in the absence of reducing thiols or acetyl coenzyme A or was treated with thiol-alkylating agents, suggesting the presence of at least one essential cysteine residue in or near the active site. The acetyltransferase activity is greatly inhibited by its reaction product N-acetylglucosamine-1-phosphate and, interestingly, also by UDP-N-acetylmuramic Acid, which is one of the first precursors specific for the peptidoglycan pathway. The detection in crude cell extracts of a phosphoglucosamine mutase activity finally confirms that the route from glucosamine-6-phosphate to UDP-N-acetylglucosamine occurs via glucosamine-1-phosphate in bacteria.