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See detailInteraction of ceftobiprole with the low-affinity PBP 5 of Enterococcus faecium
Henry, X.; Amoroso, Ana Maria ULg; Coyette, Jacques ULg et al

in Antimicrobial Agents and Chemotherapy (2010), 54

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See detailPBP5 complementation of a PBP3 deficiency in Enterococcus hirae
Leimanis, S.; Hoyez, N.; Hubert, S et al

in Journal of Bacteriology (2006), 188(17), 6298-6307

The low susceptibility of enterococci to beta-lactams is due to the activity of the low-affinity penicillin-binding protein 5 (PBP5). One important feature of PBP5 is its ability to substitute for most ... [more ▼]

The low susceptibility of enterococci to beta-lactams is due to the activity of the low-affinity penicillin-binding protein 5 (PBP5). One important feature of PBP5 is its ability to substitute for most, if not all, penicillin-binding proteins when they are inhibited. That substitution activity was analyzed in Enterococcus hirae SL2, a mutant whose pbp5 gene was interrupted by the nisRK genes and whose PBP3 synthesis was submitted to nisin induction. Noninduced SL2 cells were unable to divide except when plasmid-borne pbp5 genes were present, provided that the PBP5 active site was functional. Potential protein-protein interaction sites of the PBP5 N-terminal module were mutagenized by site-directed mutagenesis. The T-167-L-184 region (designated site D) appeared to be an essential intramolecular site needed for the stability of the protein. Mutations made in the two globular domains present in the N-terminal module indicated that they were needed for the suppletive activity. The P-197-N-209 segment (site E) in one of these domains seemed to be particularly important, as single and double mutations reduced or almost completely abolished, respectively, the action of PBP5. [less ▲]

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See detailThe ponA gene of Enterococcus faecalis JH2-2 codes for a low-affinity class a penicillin-binding protein
Duez, Colette ULg; Hallut, Séverine; Rhazi, Noureddine ULg et al

in Journal of Bacteriology (2004), 186(13), 4412-4416

soluble derivative of the Enterococcus faecalis JH2-2 class A PBP1 (*PBP1) was overproduced and purified. It exhibited a glycosyltransferase activity on the Escherichia coli (14)C(-)labeled lipid 11 ... [more ▼]

soluble derivative of the Enterococcus faecalis JH2-2 class A PBP1 (*PBP1) was overproduced and purified. It exhibited a glycosyltransferase activity on the Escherichia coli (14)C(-)labeled lipid 11 precursor. As a DD-peptidase, it could hydrolyze thiolester substrates with efficiencies similar to those of other class A penicillin-binding proteins (PBPs) and bind beta-lactams, but with k(2)/K (a parameter accounting for the acylation step efficiency) values characteristic of penicillin-resistant PBPs. [less ▲]

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See detailRedefining the role of psr in beta-lactam resistance and cell autolysis of Enterococcus hirae.
Sapunaric, Frédéric ULg; Franssen, Christine; Stefanic, Patrick et al

in Journal of Bacteriology (2003), 185(20), 5925-35

The contribution of penicillin-binding protein 5 (PBP5) and the PBP5 synthesis repressor (Psr) to the beta-lactam resistance, growth, and cell autolysis of wild-type strain ATCC 9790 and resistant strain ... [more ▼]

The contribution of penicillin-binding protein 5 (PBP5) and the PBP5 synthesis repressor (Psr) to the beta-lactam resistance, growth, and cell autolysis of wild-type strain ATCC 9790 and resistant strain R40 of Enterococcus hirae was investigated by disruption or substitution of the corresponding pbp5 and psr genes by Campbell-type recombination. The resulting modifications were confirmed by hybridization and PCR. The low susceptibility of E. hirae to beta-lactams was confirmed to be largely dependent on the presence of PBP5. However, against all expectations, inactivation of psr in ATCC 9790 or complementation of R40 cells with psr did not modify the susceptibility to benzylpenicillin or the growth and cell autolysis rates. These results indicated that the psr gene does not seem to be involved in the regulation of PBP5 synthesis and consequently in beta-lactam resistance or in the regulation of cell autolysis in E. hirae. [less ▲]

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See detailThe 2.4-A crystal structure of the penicillin-resistant penicillin-binding protein PBP5fm from Enterococcus faecium in complex with benzylpenicillin.
Sauvage, Eric ULg; Kerff, Frédéric ULg; Fonze, E. et al

in Cellular and Molecular Life Sciences : CMLS (2002), 59(7), 1223-32

Penicillin-binding proteins (PBPs) are membrane proteins involved in the final stages of peptidoglycan synthesis and represent the targets of beta-lactam antibiotics. Enterococci are naturally resistant ... [more ▼]

Penicillin-binding proteins (PBPs) are membrane proteins involved in the final stages of peptidoglycan synthesis and represent the targets of beta-lactam antibiotics. Enterococci are naturally resistant to these antibiotics because they produce a PBP, named PBP5fm in Enterococcus faecium, with low-level affinity for beta-lactams. We report here the crystal structure of the acyl-enzyme complex of PBP5fm with benzylpenicillin at a resolution of 2.4 A. A characteristic of the active site, which distinguishes PBP5fm from other PBPs of known structure, is the topology of the loop 451-465 defining the left edge of the cavity. The residue Arg464, involved in a salt bridge with the residue Asp481, confers a greater rigidity to the PBP5fm active site. In addition, the presence of the Val465 residue, which points into the active site, reducing its accessibility, could account for the low affinity of PBP5fm for beta-lactam. This loop is common to PBPs of low affinity, such as PBP2a from Staphylococcus aureus and PBP3 from Bacillus subtilis. Moreover, the insertion of a serine after residue 466 in the most resistant strains underlines even more the determining role of this loop in the recognition of the substrates. [less ▲]

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See detailThe Penicillin Resistance of Enterococcus Faecalis Jh2-2r Results from an Overproduction of the Low-Affinity Penicillin-Binding Protein Pbp4 and Does Not Involve a Psr-Like Gene
Duez, Colette ULg; Zorzi, Willy ULg; Sapunaric, Frédéric ULg et al

in Microbiology (2001), 147(Pt 9), 2561-9

A penicillin-resistant mutant, JH2-2r (MIC 75 microg ml(-1)), was isolated from Enterococcus faecalis JH2-2 (MIC 5 microg ml(-1)) by successive passages on plates containing increasing concentrations of ... [more ▼]

A penicillin-resistant mutant, JH2-2r (MIC 75 microg ml(-1)), was isolated from Enterococcus faecalis JH2-2 (MIC 5 microg ml(-1)) by successive passages on plates containing increasing concentrations of benzylpenicillin. A comparison of the penicillin-binding protein (PBP) profiles in the two strains revealed a more intensely labelled PBP4 in JH2-2r. Because the sequences of the JH2-2 and JH2-2r pbp4 genes were strictly identical, even in their promoter regions, this intensive labelling could only be associated with an overproduction of the low-affinity PBP4. No psr gene analogous to that proposed to act as a regulator of PBP5 synthesis in Enterococcus hirae and Enterococcus faecium could be identified in the vicinity of pbp4 in E. faecalis JH2-2 and JH2-2r. However, a psr-like gene distant from pbp4 was identified. The cloning and sequencing of that psr-like gene from both E. faecalis strains indicated that they were identical. It is therefore postulated that the PBP4 overproduction in E. faecalis JH2-2r results from the modification of an as yet unidentified factor. [less ▲]

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See detailThe Gene Encoding the Low-Affinity Penicillin-Binding Protein 3r in Enterococcus Hirae S185r Is Borne on a Plasmid Carrying Other Antibiotic Resistance Determinants
Raze, Dominique; Dardenne, Olivier ULg; Hallut, Séverine et al

in Antimicrobial Agents and Chemotherapy (1998), 42(3), 534-539

Two plasmid-derived NcoI DNA fragments of 14 and 4.5 kb, respectively, have been isolated from the multidrug-resistant strain Enterococcus hirae S185R and analyzed. The 14-kb fragment contains two ... [more ▼]

Two plasmid-derived NcoI DNA fragments of 14 and 4.5 kb, respectively, have been isolated from the multidrug-resistant strain Enterococcus hirae S185R and analyzed. The 14-kb fragment contains two inverted (L and R) IS1216 insertion modules of the ISS1 family. These modules define a Tn5466 transposon-like structure that contains one copy of the methylase-encoding ermAM conferring erythromycin resistance and one copy of the adenylyl-transferase-encoding aadE conferring streptomycin resistance. Immediately on the left side of IS1216L there occurs a copy of pbp3r encoding the low-affinity penicillin-binding protein (PBP) PBP3r, itself preceded by a psr-like gene (psr3r) that controls the synthesis of PBP3r. ermAM, aadE, and the transposase gene (tnp) of IS1216R have the same polarities, and these are opposite those of psr3r, pbp3r, and the tnp gene of IS1216L. The 4.5-kb fragment is a copy of the 4.5-kb sequence at the 5' end of the 14-kb fragment, although it is not a restriction product of the 14-kb fragment. It contains three genes with the same polarity: psr3r, pbp3r, and tnp in an IS1216 element. Because of the very high degree of identity (99%) with the chromosomal psrfm and pbp5fm genes of Enterococcus faecium D63R, it is proposed that both the psr3r and pbp3r genes were transferred from an E.faecium strain and inserted in a plasmid of E. hirae. E. hirae is the first known bacterial species in which a low-affinity PBP-encoding gene has been found to be plasmid borne. [less ▲]

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See detailRésistance bactérienne aux beta-lactamines
Charlier, Paulette ULg; Coyette, Jacques ULg; Dehareng, Dominique ULg et al

in Medecine Sciences : M/S (1998), 14(5), 544-555

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See detailPenicillin-binding proteins. Wall peptidoglycan assembly and resistance to penicillin: facts, doubts and hopes
Ghuysen, Jean-Marie ULg; Charlier, Paulette ULg; Coyette, Jacques ULg et al

in International Journal of Antimicrobial Agents (1997), 8(1), 45-60

As the protein sequence and structure databases expand, the relationships between proteins, the notion of protein superfamily, and the driving forces of evolution are better understood. Key steps of the ... [more ▼]

As the protein sequence and structure databases expand, the relationships between proteins, the notion of protein superfamily, and the driving forces of evolution are better understood. Key steps of the synthesis of the bacterial cell wall peptidoglycan are revisited in light of these advances. The reactions through which the D-alanyl-D-alanine depeptide is formed, utilized, and hydrolyzed and the sites of action of the glycopeptide and β-lactam antibiotics illustrate the concept according to which new enzyme functions evolve as a result of tinkering of existing proteins. This occurs by the acquisition of local structural changes, the fusion into mul-timodular polypeptides, and the association into multiprotein complexes. [less ▲]

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See detailImportance of the E-46-D-160 Polypeptide Segment of the Non-Penicillin-Binding Module for the Folding of the Low-Affinity, Multimodular Class B Penicillin-Binding Protein 5 of Enterococcus Hirae
Mollerach, Marta E.; Partoune, Pierre; Coyette, Jacques ULg et al

in Journal of Bacteriology (1996), 178(6), 1774-1775

Compared with the other class B multimodular penicillin- binding proteins (PBPs), the low-affinity PBP5 responsible for penicillin resistance in Enterococcus hirae R40, has an extended non-penicillin ... [more ▼]

Compared with the other class B multimodular penicillin- binding proteins (PBPs), the low-affinity PBP5 responsible for penicillin resistance in Enterococcus hirae R40, has an extended non-penicillin-binding module because of the presence of an approximately 110-amino-acid E-46(-)D-160 insert downstream from the membrane anchor. Expression of pbp5 genes lacking various parts of the insert-encoding region gives rise to proteins that are inert in terms of penicillin binding, showing that during folding of the PBP, the insert plays a role in the acquisition of a correct penicillin-binding configuration by the G-364(-)Q-678 carboxy-terminal module. [less ▲]

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See detailModular Design of the Bi(multi?) functional penicillin-binding proteins
Englebert, Serge; El Kharroubi, Aboubaker; Piras, Graziella et al

in De pedro; Höltje, J. V.; Loffelhardt, W. (Eds.) Bacterial Growth & Lysis Metabolism and Structure of the Bacterial Sacculus (1993)

Proceedings of a symposium held in Mallorca, Spain in April 1992. The goal of the meeting was to assess the present state of knowledge on the structure and physiology of the bacterium murien sacculus, and ... [more ▼]

Proceedings of a symposium held in Mallorca, Spain in April 1992. The goal of the meeting was to assess the present state of knowledge on the structure and physiology of the bacterium murien sacculus, and develop new hypotheses and strategies to promote further development of the field. The contributions reflect broadly different approaches. Papers discuss structure and chemistry, biosynthesis and maturation, regulation and control of cell wall hydrolases, penicillin interactive proteins, morphogenesis and septum formation, and cell growth. Annotation c. Book News, Inc., Portland, OR (booknews.com) [less ▲]

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See detailAntibacterial activity of 5-acylaminothiazole derivatives, synthetic drugs related to β-lactam antibiotics
Pirotte, Bernard ULg; Delarge, Jacques; Coyette, Jacques ULg et al

in Journal of Antibiotics (The) (1991), 44

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See detailAcyltransferase activities of the high-molecular-mass essential penicillin-binding proteins
Adam, Maggy; Damblon, Christian ULg; Jamin, Marc et al

in Biochemical Journal (1991), 279(Part 2), 601-604

The high-molecular-mass penicillin-binding proteins (HMM-PBPs), present in the cytoplasmic membranes of all eubacteria, are involved in important physiological events such as cell elongation, septation or ... [more ▼]

The high-molecular-mass penicillin-binding proteins (HMM-PBPs), present in the cytoplasmic membranes of all eubacteria, are involved in important physiological events such as cell elongation, septation or shape determination. Up to now it has, however, been very difficult or impossible to study the catalytic properties of the HMM-PBPs in vitro. With simple substrates, we could demonstrate that several of these proteins could catalyse the hydrolysis of some thioesters or the transfer of their acyl moiety on the amino group of a suitable acceptor nucleophile. Many of the acyl-donor substrates were hippuric acid or benzoyl-D-alanine derivatives, and their spectroscopic properties enabled a direct monitoring of the enzymic reaction. In their presence, the binding of radioactive penicillin to the PBPs was also inhibited. [less ▲]

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See detailCharacterization of an Enterococcus Hirae Penicillin-Binding Protein 3 with Low Penicillin Affinity
Piras, Graziella; El Kharroubi, Aboubaker; van Beeumen, Jozef et al

in Journal of Bacteriology (1990), 172(12), 6856-6862

Enterococcus hirae S185, a clinical isolate from swine intestine, exhibits a relatively high resistance to penicillin and contains two 77-kDa penicillin-binding proteins 3 of high (PBP 3s) and low (PBP 3r ... [more ▼]

Enterococcus hirae S185, a clinical isolate from swine intestine, exhibits a relatively high resistance to penicillin and contains two 77-kDa penicillin-binding proteins 3 of high (PBP 3s) and low (PBP 3r) affinity to penicillin, respectively. A laboratory mutant S185r has been obtained which overproduces PBP 3r and has a highly increased resistance to penicillin. Peptide fragments specifically produced by trypsin and SV8 protease digestions of PBP 3r were isolated, and the amino acid sequences of their amino terminal regions were determined. On the basis of these sequences, oligonucleotides were synthesized and used as primers to generate, by polymerization chain reaction, a 233-bp DNA fragment the sequence of which translated into a 73-amino-acid peptide segment of PBP 3r. These structural data led to the conclusion that the E. hirae PBP 3r and the methicillin-resistant staphylococcal PBP 2' are members of the same class of high-Mr PBPs. As shown by immunological tests, PBP 3r is not related to PBP 3s but, in contrast, is related to the 71-kDa PBP 5 of low penicillin affinity which is responsible for penicillin resistance in E. hirae ATCC 9790 and R40. [less ▲]

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See detailCharacterization of the Trypsin-Solubilized Penicillin-Binding Proteins of Enterococcus hirae (Streptococcus faecium)
El Kharroubi, Aboubaker; Jacques, Philippe; Piras, Graziella 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 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 detailActive-site-serine D-alanyl-D-alanine-cleaving-peptidase-catalysed acyl-transfer reactions. Procedures for studying the penicillin-binding proteins of bacterial plasma membranes
Ghuysen, Jean-Marie ULg; Frère, Jean-Marie ULg; Leyh-Bouille, Mélina et al

in Biochemical Journal (1986), 235(1), 159-165

Under certain conditions, the values of the parameters that govern the interactions between the active-site-serine D-alanyl-D-alanine-cleaving peptidases and both carbonyl-donor substrates and beta-lactam ... [more ▼]

Under certain conditions, the values of the parameters that govern the interactions between the active-site-serine D-alanyl-D-alanine-cleaving peptidases and both carbonyl-donor substrates and beta-lactam suicide substrates can be determined on the basis of the amounts of (serine ester-linked) acyl-protein formed during the reactions. Expressing the 'affinity' of a beta-lactam compound for a DD-peptidase in terms of second-order rate constant of enzyme acylation and first-order rate constant of acyl-enzyme breakdown rests upon specific features of the interaction (at a given temperature) and permits study of structure-activity relationships, analysis of the mechanism of intrinsic resistance and use of a 'specificity index' to define the capacity of a beta-lactam compound of discriminating between various sensitive enzymes. From knowledge of the first-order rate constant of acyl-enzyme breakdown and the given time of incubation, the beta-lactam compound concentrations that are necessary to achieve given extents of DD-peptidase inactivation can be converted into the second-order rate constant of enzyme acylation. The principles thus developed can be applied to the study of the multiple penicillin-binding proteins that occur in the plasma membranes of bacteria. [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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See detailBacterial wall peptidoglycan, DD-peptidases and beta-lactam antibiotics
Ghuysen, Jean-Marie ULg; Frère, Jean-Marie ULg; Leyh-Bouille, Mélina et al

in Scandinavian Journal of Infectious Diseases (1984), 42

Wall peptidoglycan expansion in bacteria rests upon a cytoplasmic D-Ala: D-Ala ligase (ADP) which catalyses synthesis of a D-Ala-D-Ala dipeptide (with accompanying hydrolysis of one molecule of ATP) and a ... [more ▼]

Wall peptidoglycan expansion in bacteria rests upon a cytoplasmic D-Ala: D-Ala ligase (ADP) which catalyses synthesis of a D-Ala-D-Ala dipeptide (with accompanying hydrolysis of one molecule of ATP) and a set of DD-peptidases which utilize this D-Ala-D-Ala dipeptide--once it has been translocated at the outer face of the plasma membrane as the C-terminal portion of a disaccharide peptide unit--as carbonyl donor for transpeptidation and carboxypeptidation reactions (without additional energy expenditure). Four DD-peptidases have been selected which differ from each other with respect to the effects that amino compounds exert on the fate and rate of consumption of a D-Ala-D-Ala terminated amide carbonyl donor analogue. They serve as models to understand the different mechanisms by which the DD-peptidases perform catalysis and show widely varying responses to the action of beta-lactams, from extreme sensitivity to very high resistance. [less ▲]

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See detailOn the Active Centers of Serine and Zn II DD-carboxyppetidases
Charlier, Paulette ULg; Coyette, Jacques ULg; Dideberg, Otto et al

in Gregory, G.I. (Ed.) Recent advances in the Chemistry of beta-lactam antibiotics (1980)

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