References of "Joris, Bernard"
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See detailQuantitative Relationship between Sensitivity to Beta-Lactam Antibiotics and Beta-Lactamase Production in Gram-Negative Bacteria--II. Non-Steady-State Treatment and Progress Curves
Frère, Jean-Marie ULg; Joris, Bernard ULg; Crine, Michel ULg et al

in Biochemical Pharmacology (1989), 38(9), 1427-33

A non-steady-state model is discussed for the study of the interplay between beta-lactamase activity and outer membrane permeability with slowly hydrolysed beta-lactams. The analysis shows: (1) that the ... [more ▼]

A non-steady-state model is discussed for the study of the interplay between beta-lactamase activity and outer membrane permeability with slowly hydrolysed beta-lactams. The analysis shows: (1) that the simple, steady-state model presented in the accompanying paper remains valid as long as kcat (i.e. k3 with chromosome-encoded class C beta-lactamases) is larger than 10(-3)/sec (generation time = 20 min or more); (2) that among the beta-lactam antibiotics studied here, the complete, non-steady-state model needs only be used in the case of aztreonam; (3) that the term "trapping" should be replaced by "formation of a covalent acyl-enzyme" and that such a phenomenon only contributes significantly to the resistance when penetration and hydrolysis are very slow and the periplasmic beta-lactamase concentration is very high. Aztreonam seems to be the only compound which fulfils the first two conditions. [less ▲]

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See detailThe Streptomyces K15 DD-peptidase/penicillin-binding protein. Active site and sequence of the N-terminal region.
Leyh-Bouille, Mélina; Vanbeeumen, Jozef; Renier-Pirlot, Suzanne et al

in Biochemical Journal (1989), 260(2), 601-604

The N-terminal region of the Streptomyces K15 DD-peptidase/penicillin-binding protein shows high homology with that of other penicillin-interactive proteins or domains. The active-site serine residue of ... [more ▼]

The N-terminal region of the Streptomyces K15 DD-peptidase/penicillin-binding protein shows high homology with that of other penicillin-interactive proteins or domains. The active-site serine residue of the conserved tetrad Ser-Xaa-Xaa-Lys occurs at position 35. There is no indication for the presence of a signal peptide or an N-terminal hydrophobic sequence, suggesting that the Streptomyces K15 enzyme is probably anchored to the membrane by a C-terminal peptide segment. [less ▲]

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See detailSequence and Comparative Analysis of Three Enterobacter Cloacae Ampc Beta-Lactamase Genes and Their Products
Galleni, Moreno ULg; Lindberg, F.; Normark, S. et al

in Biochemical Journal (1988), 250(3), 753-60

The sequences of three Enterobacter cloacae ampC beta-lactamase genes have been determined. The deduced amino acid sequences are very similar: out of a total of 361 residues, only eight positions were ... [more ▼]

The sequences of three Enterobacter cloacae ampC beta-lactamase genes have been determined. The deduced amino acid sequences are very similar: out of a total of 361 residues, only eight positions were found to be variable, and several mutations yielded residues with very similar properties. The kinetic properties of two of the enzymes were not significantly different. The three enzymes also exhibited a high degree of homology (greater than 70%) with the ampC beta-lactamases of Escherichia coli K12 and Citrobacter freundii, confirming the homogeneity of class-C beta-lactamases. [less ▲]

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See detailThe Active-Site-Serine Penicillin-Recognizing Enzymes as Members of the Streptomyces R61 Dd-Peptidase Family
Joris, Bernard ULg; Ghuysen, Jean-Marie ULg; Dive, Georges ULg et al

in Biochemical Journal (1988), 250(2), 313-324

Homology searches and amino acid alignments, using the Streptomyces R61 DD-peptidase/penicillin-binding protein as reference, have been applied to the beta-lactamases of classes A and C, the Oxa-2 beta ... [more ▼]

Homology searches and amino acid alignments, using the Streptomyces R61 DD-peptidase/penicillin-binding protein as reference, have been applied to the beta-lactamases of classes A and C, the Oxa-2 beta-lactamase (considered as the first known member of an additional class D), the low-Mr DD-peptidases/penicillin-binding proteins (protein no. 5 of Escherichia coli and Bacillus subtilis) and penicillin-binding domains of the high-Mr penicillin-binding proteins (PBP1A, PBP1B, PBP2 and PBP3 of E. coli). Though the evolutionary distance may vary considerably, all these penicillin-interactive proteins and domains appear to be members of a single superfamily of active-site-serine enzymes distinct from the classical trypsin or subtilisin families. The amino acid alignments reveal several conserved boxes that consist of strict identities or homologous amino acids. The significance of these boxes is highlighted by the known results of X-ray crystallography, chemical derivatization and site-directed-mutagenesis experiments. [less ▲]

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See detailStructure-Activity Relationships in the Beta-Lactam Family: An Impossible Dream
Frère, Jean-Marie ULg; Joris, Bernard ULg; Varetto, Louis ULg et al

in Biochemical Pharmacology (1988), 37(1), 125-32

The difficulty of establishing structure-activity relationships in the beta-lactam family of antibiotics stems from the fact that: (1) The targets in various bacteria exhibit widely different ... [more ▼]

The difficulty of establishing structure-activity relationships in the beta-lactam family of antibiotics stems from the fact that: (1) The targets in various bacteria exhibit widely different sensitivities. (2) Some bacteria produce beta-lactamases, enzymes capable of destroying the antibiotics. The rates of the reactions with the beta-lactamases and the target enzymes are not necessarily related. (3) In Gram-negative bacteria, the diffusion rate through the outer membrane varies independently from the two other factors. [less ▲]

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See detailPurification and Characterization of a β-lactam-Resistant Penicillin-Binding Protein from Enterococcus hirae (Streptococcus faecium)
Jacques, Philippe; El Kharroubi, Aboubaker; Joris, Bernard ULg et al

in Actor, Paul; Daneo-Moore, Lolita; Higgins, Michael L. (Eds.) et al Antibiotic Inhibition of Bacterial Cell Surface Assembly and Function (1988)

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See detailChromosome-encoded beta-lactamases of Citrobacter diversus. Interaction with beta-iodopenicillanate and labelling of the active site.
Amicosante, G; Oratore, A; Joris, Bernard ULg et al

in Biochemical Journal (1988), 254(3), 891-3

Both forms of the chromosome-encoded beta-lactamase of Citrobacter diversus react with beta-iodopenicillanate at a rate characteristic of class A beta-lactamases. The active site of form I was labelled ... [more ▼]

Both forms of the chromosome-encoded beta-lactamase of Citrobacter diversus react with beta-iodopenicillanate at a rate characteristic of class A beta-lactamases. The active site of form I was labelled with the same reagent. The sequence of the peptide obtained after trypsin hydrolysis is identical with that of a peptide obtained in a similar manner from the chromosome-encoded beta-lactamase of Klebsiella pneumoniae. [less ▲]

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See detailPenicillin-recognizing enzymes
Frère, Jean-Marie ULg; Joris, Bernard ULg; Dideberg, Otto et al

in Biochemical Society Transactions (1988), 16(6), 934-938

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See detailBeta-Lactamases as the Main Resistance Factor to Penicillin-Related Antibiotics
Frère, Jean-Marie ULg; Joris, Bernard ULg

in Annales de Biologie Clinique (1988), 46(2), 151-6

The interplay between the three factors involved in the resistance of bacteria to beta-lactam antibiotics (sensitivity of target, synthesis of beta-lactamase, permeability barrier) is analysed and ... [more ▼]

The interplay between the three factors involved in the resistance of bacteria to beta-lactam antibiotics (sensitivity of target, synthesis of beta-lactamase, permeability barrier) is analysed and discussed on the basis of a simple kinetic model. The three factors do not act independently. In Gram-negative bacteria, the permeability barrier is only significant when the bacterial cell also produces a beta-lactamase. Special attention is devoted to cases where large periplasmic beta-lactamase concentrations prevail, a situation which has been observed in some clinical isolates. [less ▲]

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See detailBeta-Lactamase-induced resistance
Frère, Jean-Marie ULg; Joris, Bernard ULg

in Actor, Paul; Daneo-Moore, Lolita; Higgins, Michael, L. (Eds.) et al Antibiotic Inhibition of Bacterial Cell Surface Assembly and Function (1988)

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See detailNucleotide sequence of the gene encoding the Streptomyces albus G β-lactamase precursor
Dehottay, Philippe; Dusart, Jean; De Meester, Fabien et al

in European Journal of Biochemistry (1987), 166(2), 345-350

A 1400-base DNA fragment, which contains the gene encoding the extracellular active-site serine beta-lactamase of Streptomyces albus G previously cloned into Streptomyces lividans [Dehottay et al. (1986 ... [more ▼]

A 1400-base DNA fragment, which contains the gene encoding the extracellular active-site serine beta-lactamase of Streptomyces albus G previously cloned into Streptomyces lividans [Dehottay et al. (1986) Gene 42, 31-36], was sequenced. The gene codes for a 314-amino-acid precursor, the N-terminal region of which has the characteristics of a signal peptide. The beta-lactamase as excreted by the host strain S. lividans PD6 has a ragged N-terminus, indicating either the presence of a leader peptidase of poor specificity or the action of an aminopeptidase. The primary structure (as deduced from the nucleotide sequence) was confirmed by amino acid sequencing of a 16-residue stretch at the amino terminus of the protein, a 12-residue stretch containing the active-site serine [De Meester et al. (1987) Biochem. J. 244, 427-432] and a 23-residue stretch obtained by trypsin digestion of the protein. The beta-lactamase belongs to class A, has three half-cystine residues (one of which occurs on the amino side of the active-site serine) and is inactivated by thiol reagents. Putative ribosome binding site and terminator region were identified. [less ▲]

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See detailPrimary structure of the Streptomyces R61 extracellular DD-peptidase. 2. Amino acid sequence data
Joris, Bernard ULg; Jacques, Philippe; Frère, Jean-Marie ULg et al

in European Journal of Biochemistry (1987), 162(3), 519-524

In order to confirm the Streptomyces codon usage, the Streptomyces R61 DD-peptidase was fragmented by cyanogen bromide cleavage of the carboxymethylated protein, trypsin digestion of the carboxymethylated ... [more ▼]

In order to confirm the Streptomyces codon usage, the Streptomyces R61 DD-peptidase was fragmented by cyanogen bromide cleavage of the carboxymethylated protein, trypsin digestion of the carboxymethylated protein and trypsin digestion of the protein treated with beta-iodopenicillinate and endoxo-delta 4-tetrahydrophthalic acid. The isolated peptides, which altogether represented more than 50% of the polypeptide chain, were sequenced. The data thus obtained were in excellent agreement with the primary structure of the protein as deduced from the nucleotide sequence of the cloned gene. Though a weak acylating agent, beta-iodopenicillanate reacted selectively with the active site of the DD-peptidase and formed an adduct which mas much more stable than that formed with benzylpenicillin, thus facilitating the isolation and characterization of the active-site peptide. [less ▲]

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See detailThe active sites of the β-lactamases of Streptomyces cacaoi and Streptomyces albus G
Demeester, Fabien; Joris, Bernard ULg; Lenzini, Mauro V. et al

in Biochemical Journal (1987), 244(2), 427-432

The active-site serine of the extracellular beta-lactamases of Streptomyces cacaoi and Streptomyces albus G has been labelled with beta-iodopenicillanate. The determination of the sequence of the labelled ... [more ▼]

The active-site serine of the extracellular beta-lactamases of Streptomyces cacaoi and Streptomyces albus G has been labelled with beta-iodopenicillanate. The determination of the sequence of the labelled peptides obtained after trypsin digestion of the denatured proteins indicate both enzymes to be class A beta-lactamases. Surprisingly the two Streptomyces enzymes do not appear to be especially homologous, and none of them exhibited a high degree of homology with the Streptomyces R61 DD-peptidase. Our data confirm that, as a family of homologous enzymes, class A is rather heterogeneous, with only a small number of conserved residues in all members of the class. [less ▲]

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See detailThe K1 beta-lactamase of Klebsiella pneumoniae.
Joris, Bernard ULg; De Meester, F; Galleni, Moreno ULg et al

in Biochemical Journal (1987), 243(2), 561-7

beta-Lactamase K1 was purified from Klebsiella pneumoniae SC10436. It is very similar to the enzyme produced by Klebsiella aerogenes 1082E and described by Emanuel, Gagnon & Waley [Biochem. J. (1986) 234 ... [more ▼]

beta-Lactamase K1 was purified from Klebsiella pneumoniae SC10436. It is very similar to the enzyme produced by Klebsiella aerogenes 1082E and described by Emanuel, Gagnon & Waley [Biochem. J. (1986) 234, 343-347]. An active-site peptide was isolated after labelling of the enzyme with tritiated beta-iodopenicillanate. A cysteine residue was found just before the active-site serine residue. This result could explain the properties of the enzyme after modification by thiol-blocking reagents. The sequence of the active-site peptide clearly established the enzyme as a class A beta-lactamase. [less ▲]

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See detailAutomated analysis of enzyme inactivation phenomena. Application to beta-lactamases and DD-peptidases.
De Meester, Fabien; Joris, Bernard ULg; Reckinger, Georges et al

in Biochemical Pharmacology (1987), 36

In the presence of a reporter substrate, the progressive inactivation of an enzyme was easily studied by directly transmitting absorbance readings to a microcomputer. Pseudo-first order rate constants as ... [more ▼]

In the presence of a reporter substrate, the progressive inactivation of an enzyme was easily studied by directly transmitting absorbance readings to a microcomputer. Pseudo-first order rate constants as high as 0.3 sec-1 were rapidly and accurately measured. When utilization of the reporter substrate did not exceed 10%, the rate of the reaction (vt) could be considered as proportional to the active enzyme concentration at any time during the analysis and the decrease of vt was first order with time. This simple method was used to follow the inactivation of beta-lactamases (EC 3.5.2.6) by various physical and chemical agents. When a large proportion (30-80%) of reporter substrate was destroyed, a correction was introduced to account for the corresponding decrease of its rate of utilization. This enabled experiments to be performed with a DD-peptidase and a substrate exhibiting a low delta epsilon upon hydrolysis. For the first time, the inactivation of a penicillin-sensitive enzyme by a beta-lactam could be continuously and directly observed. Finally, the method was extended to the study of hysteresis phenomena. [less ▲]

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See detailPrimary structure of the Streptomyces R61 extracellular DD-peptidase. 1. Cloning into Streptomyces lividans and nucleotide sequence of the gene
Duez, Colette ULg; Fraipont, Claudine ULg; Joris, Bernard ULg et al

in European Journal of Biochemistry (1987), 162

An 11450-base DNA fragment containing the gene for the extracellular active-site serine DD-peptidase of Streptomyces R61 was cloned in Streptomyces lividans using the high-copy-number plasmid pIJ702 as ... [more ▼]

An 11450-base DNA fragment containing the gene for the extracellular active-site serine DD-peptidase of Streptomyces R61 was cloned in Streptomyces lividans using the high-copy-number plasmid pIJ702 as vector. Amplified expression of the excreted enzyme was observed. Producing clones were identified with the help of a specific antiserum directed against the pure DD-peptidase. The coding sequence of the gene was then located by hybridization with a specific nucleotide probe and sub-fragments were obtained from which the nucleotide sequence of the structural gene and the putative promoter and terminator regions were determined. The sequence suggests that the gene codes for a 406-amino-acid protein precursor. When compared with the excreted, mature DD-peptidase, this precursor possesses a cleavable 31-amino-acid N-terminal extension which has the characteristics of a signal peptide, and a cleavable 26-amino-acid C-terminal extension. On the basis of the data of Joris et al. (following paper in this journal), the open reading frame coding for the synthesis of the DD-peptidase was established. Comparison of the primary structure of the Streptomyces R61 DD-peptidase with those of several active-site serine β-lactamases and penicillin-binding proteins of Escherichia coli shows homology in those sequences that comprise the active-site serine residue. When the comparison is broadened to the complete amino acid sequences, significant homology is observed only for the pair Streptomyces R61 DD-peptidase/Escherichia coli ampC β-lactamase (class C). Since the Streptomyces R61 DD-peptidase and β-lactamases of class A have very similar three-dimensional structures [Kelly et al. (1986) Science (Wash. DC) 231, 1429–1431; Samraoui et al. (1986) Nature (Lond.) 320, 378–380], it is concluded that these tertiary features are probably also shared by the β-lactamases of class C, i.e. that the Streptomyces R61 DD-peptidase and the β-lactamases of classes A and C are related in an evolutionary sense. [less ▲]

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See detailOn the origin of bacterial resistance to penicillin: comparison of a beta-lactamase and a penicillin target
Kelly, Judith A.; Dideberg, Otto; Charlier, Paulette ULg et al

in Science (1986), 231

Structural data are now available for comparing a penicillin target enzyme, the D-alanyl-D-alanine-peptidase from Streptomyces R61, with a penicillin-hydrolyzing enzyme, the beta-lactamase from Bacillus ... [more ▼]

Structural data are now available for comparing a penicillin target enzyme, the D-alanyl-D-alanine-peptidase from Streptomyces R61, with a penicillin-hydrolyzing enzyme, the beta-lactamase from Bacillus licheniformis 749/C. Although the two enzymes have distinct catalytic properties and lack relatedness in their overall amino acid sequences except near the active-site serine, the significant similarity found by x-ray crystallography in the spatial arrangement of the elements of secondary structure provides strong support for earlier hypotheses that beta-lactamases arose from penicillin-sensitive D-alanyl-D-alanine-peptidases involved in bacterial wall peptidoglycan metabolism. [less ▲]

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See detailProperties of a class C beta-lactamase from Serratia marcescens.
Joris, Bernard ULg; De Meester, F; Galleni, Moreno ULg et al

in Biochemical Journal (1986), 239(3), 581-6

A beta-lactamase produced by a penicillin-resistant strain of Serratia marcescens was isolated and purified. The kcat. value for benzylpenicillin was about 5% of that observed for the best cephalosporin ... [more ▼]

A beta-lactamase produced by a penicillin-resistant strain of Serratia marcescens was isolated and purified. The kcat. value for benzylpenicillin was about 5% of that observed for the best cephalosporin substrates. However, the low Km of the penam resulted in a high catalytic efficiency (kcat./Km) and the classification of the enzyme as a cephalosporinase might not be completely justified. It also exhibited a low but measurable activity against cefotaxime, cefuroxime, cefoxitin and moxalactam. Substrate-induced inactivation was observed both with a very good (cephalothin) or a very bad (moxalactam) substrate. The active site was labelled by beta-iodopenicillanate. Trypsin digestion produced a 19-residue active-site peptide whose sequence clearly allowed the classification of the enzyme as a class C beta-lactamase. [less ▲]

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See detail2.8-Å Structure of penicillin-sensitive D-alanyl carboxypeptidase-transpeptidase from Streptomyces R61 and complexes with β-lactams
Kelly, Judith A; Knox, James R; Moews, Paul C et al

in Journal of Biological Chemistry (1985), 260(10), 6449-6458

The crystallographic structure of the penicillin-sensitive D-alanyl carboxypeptidase-transpeptidase from Streptomyces R61 has been solved to 2.8-A resolution. The 38,000-dalton serine peptidase has two ... [more ▼]

The crystallographic structure of the penicillin-sensitive D-alanyl carboxypeptidase-transpeptidase from Streptomyces R61 has been solved to 2.8-A resolution. The 38,000-dalton serine peptidase has two regions of secondary structure, an alpha/beta cluster, and a region which contains five helical segments. The beta sheet is composed of five beta strands. The tertiary structure has no homology with the classic serine proteases or with the zinc carboxypeptidases. The binding at a common site of three types of beta-lactam (a penicillin, a cephalosporin, a monocyclic beta-lactam) and a desazacyclobutanone has been observed in Fourier difference maps. The binding site sequence is Val-Gly-Ser-Val-Thr-Lys. The beta-lactam ring lies near the enzyme's catalytic serine at position 37, and the C3 substituent of a cephalosporin falls near lysine 40. [less ▲]

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See detailThe beta-lactamase of Enterobacter cloacae P99. Chemical properties, N-terminal sequence and interaction with 6 beta-halogenopenicillanates.
Joris, Bernard ULg; De Meester, F; Galleni, Moreno ULg et al

in Biochemical Journal (1985), 228(1), 241-8

The beta-lactamase of Enterobacter cloacae P99 consists of one polypeptide chain of Mr 39000 devoid of disulphide bridges and free thiol groups. It contains an unusually high proportion of tyrosine and ... [more ▼]

The beta-lactamase of Enterobacter cloacae P99 consists of one polypeptide chain of Mr 39000 devoid of disulphide bridges and free thiol groups. It contains an unusually high proportion of tyrosine and tryptophan. The N-terminal sequence exhibits overlaps with the tryptic peptide obtained after labelling the active site with 6 beta-iodopenicillanate. The active-site serine residue is at position 64. The homology with the chromosomal beta-lactamase of Escherichia coli K 12 (ampC gene) is lower within the 25 residues of the N-terminal portion than around the active-site serine residue. The P99 beta-lactamase is inactivated by 6 beta-bromo- and 6 beta-iodo-penicillanate, with a second-order rate constant of 110-140M-1 X s-1 at 30 degrees C and pH 7.0, a value that is much lower than that observed with class-A beta-lactamases. [less ▲]

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