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See detailSensitivity to ampicillin and cephalothin of enzymes involved in wall peptide crosslinking in Escherichia coli K12, strain 44
Nguyen-Distèche, Martine ULg; Pollock, Jerry J.; Ghuysen, Jean-Marie ULg et al

in European Journal of Biochemistry (1974), 41(3), 457-463

After extraction of the membranes of Escherichia coli K12 strain 44 by Brij-36T, each of the four enzyme activities (natural transpeptidase, unnatural transpeptidase, carboxypeptidase and endopeptidase ... [more ▼]

After extraction of the membranes of Escherichia coli K12 strain 44 by Brij-36T, each of the four enzyme activities (natural transpeptidase, unnatural transpeptidase, carboxypeptidase and endopeptidase) of the wall peptide crosslinking system, occurs in two forms characterized by large differences in their sensitivity to ampicillin (but much smaller differences in their sensitivity to cephalothin). The fractionation of the enzyme activities into two groups of low and high sensitivity to ampicillin is achieved essentially by chromatography of the membrane extract on DEAE-cellulose. [less ▲]

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See detailEnzymes involved in wall peptide crosslinking in Escherichia coli K12, strain 44
Nguyen-Distèche, Martine ULg; Ghuysen, Jean-Marie ULg; Pollock, Jerry J. et al

in European Journal of Biochemistry (1974), 41(3), 447-455

By using the glutamate-amidated tetrapeptide l-alanyl-d-isoglutaminyl-(l)-meso-diamino-pimelyl-(l)-d-alanine as a probe, there appears to exist in the membranes of Escherichia coli K12 strain 44 a dd ... [more ▼]

By using the glutamate-amidated tetrapeptide l-alanyl-d-isoglutaminyl-(l)-meso-diamino-pimelyl-(l)-d-alanine as a probe, there appears to exist in the membranes of Escherichia coli K12 strain 44 a dd-carboxypoptidase-transpeptidase system which does not recognize this peptide and a dd-carboxypoptidase-transpeptidase system which recognizes it. The dd-carboxypeptidase-endopeptidase system is essentially hydrolytic. It catalyzes the hydrolysis of UDP-N-acetyl-muramyl-pentapeptide into UDP-N-acetylmuramyl-tetrapeptide and the hydrolysis of the wall peptidoglycan peptide dimer into monomers. These activities are not inhibited by the glutamate-amidated tetrapeptide. The system may consist either of two enzyme proteins having predominantly carboxypeptidase activity and endopeptidase activity, respectively, or of one enzyme protein of which the functioning would depend upon the environmental conditions. The dd-carboxypeptidase-transpeptidase system (a) catalyzes concomitant hydrolysis (carboxypeptidase activity) and transfer (natural model transpeptidase activity) reactions with the pentapeptide l-alanyl-γ-d-glutamyl-(l)-meso-diaminopimelyl-(l)-d-alanyl-d-alanine. The transfer reaction leads to the synthesis of a dimer that is identical to the one which occurs in the E. coli wall peptidoglycan; (b) utilizes the glutamate-amidated tetrapeptide as an acceptor. Simultaneous exposure of the pentapeptide and the glutamate-amidated tetrapeptide to the enzyme system leads to the formation of an hybrid monoamidated peptide dimer and causes a decreased hydrolysis of the pentapeptide; (c) by virtue of its own carboxypeptidase activity, it appears to exert some endopeptidase activity. Both carboxypeptidase and endopeptidase activities of this system are inhibited by the glutamate-amidated tetrapeptide, but this represents only a small fraction of the total hydrolytic activity of the membrane Brij-36T extract. (d) The system catalyzes an unnatural model transpeptidation reaction in which glycine replaces d-alanine at the C-terminal position of the nucleotide UDP-N-acetylmuramyl-pentapeptide. This system may also consist either of two enzyme proteins having predominantly natural model transpeptidase activity and unnatural model transpeptidase activity, respectively, or of one enzyme protein of which the functioning would depend upon the environmental conditions. Whatever the exact situation, the E. colidd-carboxypeptidase-transpeptidase system is in many respects, similar to the dd-carboxy-peptidase-transpeptidase single polypeptide enzymes isolated from Streptomyces strains R39 and R61. [less ▲]

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See detailFractionation of the DD-carboxypeptidase-transpeptidase activities solubilized from membranes of Escherichia coli K12, strain 44
Pollock, Jerry J.; Nguyen-Disteche, Martine; Ghuysen, Jean-Marie ULg et al

in European Journal of Biochemistry (1974), 41(3), 439-446

A transpeptidase activity in Escherichia coli was measured independently of other enzymes involved in peptidoglycan synthesis by quantitating the formation of UDP-N-acetylmuramyl-l-alanyl-y-d-glutamyl-(l ... [more ▼]

A transpeptidase activity in Escherichia coli was measured independently of other enzymes involved in peptidoglycan synthesis by quantitating the formation of UDP-N-acetylmuramyl-l-alanyl-y-d-glutamyl-(l)-meso-diaminopimelyl-(l)-d-alanyl-[14C]glycine when UDP-N-acetylmuramyl-l-alanyl-y-d-glutamyl-(l)-meso-diaminopimelyl-(l-d-alanyl-d-alanine was used as donor substrate and [14C]glycine as acceptor in a transfer reaction. After extraction of membrane envelopes with Brij-36T and subsequent ammonium sulfate precipitation, DEAE-cellulose chromatography revealed two major fractions; one not adsorbed to the ion-exchange resin and the other adsorbed. The fraction which was bound to DEAE-cellulose was bound to and could be eluted from an ampicillin affinity chromatography system while the fraction not bound to DEAE-cellulose was also not bound to the ampicillin column. Both unbound and bound ampicillin fractions exhibited dd-carboxypeptidase and transpeptidase activities although for equivalent dd-carboxypeptidase activity, the bound ampicillin fraction required about five times more glycine acceptor to achieve the same amount of transpeptidation as the unbound ampicillin fraction. [less ▲]

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See detailThe wall peptidoglycans of Neisseria perflava, Moraxella glucidolytica, Pseudomonas alcaligenes and Proteus vulgaris strain P18
Martin, Jean-Pierre; Fleck, J.; Mock, M. et al

in European Journal of Biochemistry (1973), 38(2), 301-306

The primary structure of the wall peptidoglycans of Neisseria perflava, Moraxella glucidolytica and Pseudomonas alcaligenes is similar to those of the Enterobacteriaceae Proteus vulgaris and Escherichia ... [more ▼]

The primary structure of the wall peptidoglycans of Neisseria perflava, Moraxella glucidolytica and Pseudomonas alcaligenes is similar to those of the Enterobacteriaceae Proteus vulgaris and Escherichia coli, suggesting that the peptidoglycans of all gram-negative bacteria contain meso-diaminopimelic acid and belong to the same chemotype I. Differences are observed with regard to the thickness of the peptidoglycan layer in the cell envelopes, the extent of peptide crosslinking and the occurrence of N,O-diacetylmuramic acid residues. [less ▲]

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See detailKinetics and mechanism of the exchange reactions catalysed by the oxoglutarate translocator of rat-heart mitochondria.
Sluse, Francis ULg; Goffard, George; lièbecq, Claude

in European Journal of Biochemistry (1973), 32

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See detailStructural investigations on cell walls of Nocardia sp. The wall lipid and peptidoglycan moieties of Nocardia kirovani
Vacheron, Marie-Jeanne; Guinand, Micheline; Michel, Georges et al

in European Journal of Biochemistry (1972), 29(1), 156-166

The walls of Nocardia kirovani are composed of three main constituents: the peptidoglycan matrix, a polysaccharide polymer and a variety of free and bound lipids. The free lipids represent 17.5% (dry ... [more ▼]

The walls of Nocardia kirovani are composed of three main constituents: the peptidoglycan matrix, a polysaccharide polymer and a variety of free and bound lipids. The free lipids represent 17.5% (dry weight) of the walls and consist for the major part of C16–18 fatty acids and nocardic acids, and for the minor part, of nocardones, triglycerides and carotenoid pigments. The nocardic acids were identified as tri- and tetra-unsaturated, α-branched, β-hydroxylated compounds C58H110O3—C66H124O3 the nocardones as tri-and tetra-unsaturated ketones C57H106O—C63H1180O, and the main carotenoid pigment as phlei-xantophylle palmitate. Esters of glycerol with C14, C16, C18 fatty acids and, for some of them, with odd numbered poly-unsaturated acids containing 35 to 45 carbon atoms, were also identified. Bound lipids represent about 20% (dry weight) of the walls and consist mainly of nocardic acids probably ester-linked to an arabinogalactan polymer. The peptidoglycan (about 40% dry weight) is composed of β-1,4-N-acetylglucosaminyl-N-glycolylmuramic acid disaccharide units that are substituted by diamidated L-Ala-D-αGln-(L)-A2pm-(D)-NH2 tripeptides and diamidated l-Ala-d-αGln-(L)-A2pm-(D)-NH2-(L)-d-Ala tetrapeptides, where A2pm is meso-diaminopimelic acid. Crosslinking between some of the peptide units is mediated through D-Ala-(D)-A2pm linkages (peptidoglycan of chemotype I). [less ▲]

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