References of "Frère, Jean-Marie"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailStreptomyces DD-carboxypeptidases as transpeptidases. The specificity for amino compounds acting as carboxyl acceptors
Perkins, Harnold R.; Nieto, Manuel; Frère, Jean-Marie ULg et al

in Biochemical Journal (1973), 131(4), 707-718

The ability of the water-soluble dd-carboxypeptidases of Streptomyces strains albus G, R61, K11 and R39 to perform transpeptidation was studied. The donor was diacetyl-l-lysyl-d-alanyl-d-alanine, and a ... [more ▼]

The ability of the water-soluble dd-carboxypeptidases of Streptomyces strains albus G, R61, K11 and R39 to perform transpeptidation was studied. The donor was diacetyl-l-lysyl-d-alanyl-d-alanine, and a whole range of amino acids, peptides and structurally related amino compounds were tested for acceptor function. No compound tested was an acceptor for the enzyme from strain albus G whereas the enzymes from strains R61 and K11 could utilize with varying efficiency a wide range of substances including peptides with N-terminal glycine or d-alanine, omega-amino acids, aminohexuronic acids, 6-aminopenicillanic acid and d-cycloserine. Certain peptides, when present in higher concentration, inhibited the transpeptidation observed at lower concentration. The enzyme from strain R39 would not use any dipeptide as an acceptor, but a few compounds that were not glycine or alpha-amino acids of the d-configuration did function thus. These were d-cycloserine and the lactams of meso- or racemic-diaminoadipic acid. [less ▲]

Detailed reference viewed: 7 (0 ULg)
Full Text
Peer Reviewed
See detailDD-carboxypeptidase-transpeptidase and killing site of β-lactam antibiotics in Streptomyces strains R39, R61, and K11
Dusart, Jean; Marquet, Alberto; Ghuysen, Jean-Marie ULg et al

in Antimicrobial Agents and Chemotherapy (1973), 3(2), 181-187

Additional evidence is given that in Streptomyces strains R39, R61, and K11 the same enzyme performs dd-carboxypeptidase and transpeptidase activities and that this enzyme is the killing site of beta ... [more ▼]

Additional evidence is given that in Streptomyces strains R39, R61, and K11 the same enzyme performs dd-carboxypeptidase and transpeptidase activities and that this enzyme is the killing site of beta-lactam antibiotics. With strain R61, it was found that the exocellular enzyme has a sensitivity towards some antibiotics different from that of the membrane-bound enzyme. Under the growth conditions used in the present investigations, beta-lactamase activity was not involved in susceptibility to beta-lactam antibiotics. [less ▲]

Detailed reference viewed: 6 (1 ULg)
Full Text
Peer Reviewed
See detailPeptide inhibitors of Streptomyces DD-carboxypeptidases
Nieto, Manuel; Perkins, Harnold R.; Leyh-Bouille, Mélina et al

in Biochemical Journal (1973), 131(1), 163-171

1. Peptides that inhibit the dd-carboxypeptidases from Streptomyces strains albus G and R61 were synthesized. They are close analogues of the substrates of these enzymes. The enzymes from albus G and R61 ... [more ▼]

1. Peptides that inhibit the dd-carboxypeptidases from Streptomyces strains albus G and R61 were synthesized. They are close analogues of the substrates of these enzymes. The enzymes from albus G and R61 strains are in general inhibited by the same peptides, but the enzyme from strain R39 differs considerably. 2. The two C-terminal residues of the peptide substrates and inhibitors appear to be mainly responsible for the initial binding of the substrate to the enzymes from albus G and R61 strains. The side chain in the third residue from the C-terminus seems critical in inducing catalytic activity. 3. Experimental evidence is presented suggesting that the amide bond linking the two C-terminal residues has a cis configuration when bound to the enzymes from strains albus G and R61. 4. The peptide inhibitors are not antibiotics against the same micro-organisms. [less ▲]

Detailed reference viewed: 6 (0 ULg)
Full Text
See detailDD-carboxypeptidases/Transpeptidases and Penicillin Action
Perkins, Harold R; Ghuysen, Jean-Marie ULg; Nieto, Manuel et al

in 1st International Congress for Bacteriology, Jerusalem, 2-7 September, 1973. Abstracts. Vol I. Symposia (1973)

Detailed reference viewed: 9 (0 ULg)
Full Text
Peer Reviewed
See detailStructure of the wall peptidoglycan of streptomyces R39 and the specificity profile of its exocellular DD-carboxypeptidase-transpeptidase for peptide acceptors
Ghuysen, Jean-Marie ULg; Leyh-Bouille, Mélina; Campbell, James N. et al

in Biochemistry (1973), 12(7), 1243-1251

Benzylpenicillin and cephaloridine reacted with the exocellular dd-carboxypeptidase–transpeptidase from Streptomyces R39 to form equimolar and inactive antibiotic–enzyme complexes. At saturation, the ... [more ▼]

Benzylpenicillin and cephaloridine reacted with the exocellular dd-carboxypeptidase–transpeptidase from Streptomyces R39 to form equimolar and inactive antibiotic–enzyme complexes. At saturation, the molar ratio of chromogenic cephalosporin 87-312 to enzyme was 1.3:1, but this discrepancy might be due to a lack of accuracy in the measurement of the antibiotic. Spectrophotometric studies showed that binding of cephaloridine and cephalosporin 87-312 to the enzyme caused opening of their β-lactam rings. Benzylpenicillin and cephalosporin 87-312 competed for the same site on the free enzyme, suggesting that binding of benzylpenicillin also resulted in the opening of its β-lactam ring. In Tris–NaCl–MgCl2 buffer at pH7.7 and 37°C, the rate constants for the dissociation of the antibiotic–enzyme complexes were 2.8×10−6, 1.5×10−6 and 0.63×10−6s−1 (half-lives 70, 130 and 300h) for benzylpenicillin, cephalosporin 87-312 and cephaloridine respectively. During the process, the protein underwent reactivation. The enzyme that was regenerated from its complex with benzylpenicillin was as sensitive to fresh benzylpenicillin as the native enzyme. With [14C]benzylpenicillin, the released radioactive compound was neither benzylpenicillin nor benzylpenicilloic acid. The Streptomyces R39 enzyme thus behaved as a β-lactam-antibiotic-destroying enzyme but did not function as a β-lactamase. Incubation at 37°C in 0.01m-phosphate buffer, pH7.0, and in the same buffer supplemented with sodium dodecyl sulphate caused a more rapid reversion of the [14C]benzylpenicillin–enzyme complex. The rate constants were 1.6×10−5s−1 and 0.8×10−4s−1 respectively. Under these conditions, however, there was no concomitant reactivation of the enzyme and the released radioactive compound(s) appeared not to be the same as before. The Streptomyces R39 enzyme and the exocellular dd-carboxypeptidase–transpeptidase from Streptomyces R61 appeared to differ from each other with regard to the topography of their penicillin-binding site. [less ▲]

Detailed reference viewed: 47 (3 ULg)
Full Text
Peer Reviewed
See detailPenicillin-sensitive DD-carboxypeptidases from Streptomyces strains R39 and K11
Leyh-Bouille, Mélina; Nakel, Marlies; Frère, Jean-Marie ULg et al

in Biochemistry (1972), 11(7), 1290-1298

The two penicillin-sensitive DD-carboxypeptidases from Streptomyces R39 and K11 are anionic at pH 8. They specifically recognize a C-terminal L-R3-D-alanyl-D sequence with a long side chain at the R3 ... [more ▼]

The two penicillin-sensitive DD-carboxypeptidases from Streptomyces R39 and K11 are anionic at pH 8. They specifically recognize a C-terminal L-R3-D-alanyl-D sequence with a long side chain at the R3 position. The two enzymes differ from each other with respect to: (1) the effects of ionic strength on activity, (2) the influence exerted on activity by the presence of a free amino group at the end of the L-R3 side chain, (3) the K3 and Vmax values. Enzyme K11 has Km values which are high for both good and poor substrates. The enzyme efficiency reflects itself in Vmax values which are high for good substrates and low for poor substrates. Enzyme R39 has Km values which are low for good substrates. The enzyme efficiency toward various substrates reflects itself in the Km and, to a lesser extent, in the Vmax values, (4) the effects of penicillin. Kinetically, inhibition of enzyme K11 by penicillin is competitive. On the contrary, inhibition of enzyme R39 by penicillin is noncompetitive and increasing penicillin concentrations cause disproportionate decreases in the catalytic rate. Noncompetitiveness cannot be attributed to an irreversible inactivation of the enzyme by penicillin. [less ▲]

Detailed reference viewed: 11 (2 ULg)
Full Text
Peer Reviewed
See detailTranspeptidase activity of Streptomyces D-alanyl-D carboxypeptidases
Pollock, J. J.; Ghuysen, Jean-Marie ULg; Linder, R. et al

in Proceedings of the National Academy of Sciences of the United States of America (1972), 69(3), 662-666

In the presence of N(alpha),N(epsilon)-diacetyl-L-Lys-D-Ala-D-Ala as donor, and either D-[(14)C]alanine, [(14)C]-glycine, or meso-[(3)H]diaminopimelic acid as acceptor, the DD carboxypeptidases from ... [more ▼]

In the presence of N(alpha),N(epsilon)-diacetyl-L-Lys-D-Ala-D-Ala as donor, and either D-[(14)C]alanine, [(14)C]-glycine, or meso-[(3)H]diaminopimelic acid as acceptor, the DD carboxypeptidases from Streptomyces R61 and R39 catalyze a transpeptidation reaction with the release of terminal D-alanine from the donor and the formation of either N(alpha),N(epsilon)-diacetyl-L-Lys-D-Ala-D-[(14)C]Ala, N(alpha),N(epsilon)-diacetyl-L-Lys-D-Ala-[(14)C] Gly, or N(alpha),N(epsilon)-diacetyl-L-Lys-D-Ala-D-meso- [(3)H]diaminopimelic acid. The reaction appears to be a true transpeptidation, and is not simply a "reversal of hydrolysis". Transpeptidation is inhibited by pencillin at concentrations that inhibit hydrolysis (carboxypeptidase action) of the donor peptide. There are differences in the specificity profiles of the Streptomyces enzymes for acceptor molecules:only the R61 enzyme used [(14)C]Gly-Gly as acceptor; transfer of N(alpha),N(epsilon)-diacetyl-L-Lys-D-Ala to this acceptor resulted in the formation of N(alpha),N(epsilon)-diacetyl-Lys-D-Ala-[(14)C] Gly-Gly, with the synthesis of a (D-Ala-Gly) peptide bond in an endoposition. [less ▲]

Detailed reference viewed: 9 (1 ULg)
Full Text
See detailThe Streptomyces DD-carboxypeptidase-transpeptidase system as a model for the study of penicillin action
Ghuysen, Jean-Marie ULg; Leyh-Bouille, Mélina; Frère, Jean-Marie ULg et al

in Pratesi, P. (Ed.) Medicinal Chemistry : Special contributions - Milan 1972 (1972)

A new model for the transpeptidation reaction involved in the biosynthesis of the bacterial wall peptidoglycan and for its inhibition by penicillin is proposed. This model is in open conflict with the ... [more ▼]

A new model for the transpeptidation reaction involved in the biosynthesis of the bacterial wall peptidoglycan and for its inhibition by penicillin is proposed. This model is in open conflict with the hypotheses previously postulated. It rests upon the demonstration that 1) carboxypeptidase and transpep-tidase activities are performed by the same enzyme, 2) inhibition of both activities by penicillin is carried out in the absence of irreversible acylation of the protein, 3) the enzyme contains multiple sites some of which are involved in regulation, 4) penicillin does not act as a structural analogue of the donor peptide involved in transpeptidation but may act at the level of regulatory site(s). [less ▲]

Detailed reference viewed: 15 (0 ULg)