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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 Penicillin sensory transducer, blar, involved in the inducibility of beta-lactamase synthesis in bacillus licheniformis is embedded in the plasma membrane via a four-alpha-helix bundle
Hardt, Karin; Joris, Bernard ULg; Lepage, Sophie et al

in Molecular Microbiology (1997), 23(5), 935-944

Prediction studies, conformational analyses and membrane-topology mapping lead to the conclusion that the penicillin sensory transducer, BlaR, involved in the inducibility of beta-lactamase synthesis in ... [more ▼]

Prediction studies, conformational analyses and membrane-topology mapping lead to the conclusion that the penicillin sensory transducer, BlaR, involved in the inducibility of beta-lactamase synthesis in Bacillus licheniformis, is embedded in the plasma membrane bilayer via four transmembrane segments TM1-TM4 that forma four-alpha-helix bundle. The extracellular 262-amino-acid-residue polypeptide, S340-R601, that is fused at the carboxy end of TM4, possesses the amino acid sequence signature of a penicilloyl serine transferase. It probably functions as penicillin sensor. As an independent entity, this polypeptide behaves as a high-affinity penicillin-binding protein. As a component of the full-size BlaR, it adopts a different conformation presumably because of interactions with the extracellular 63-amino-acid-residue P53-S115 loop that connects TM2 and TM3. Reception of the penicillin-induced signal requires a precise conformation of the sensor but it does not involve penicilloylation of the serine residue S402 of motif STYK. Signal transmission through the plasma membrane by the four-alpha-helix bundle may proceed in a way comparable to that of the aspartate receptor, Tar. Signal emission in the cytosol by the intracellular 189-amino-acid-residue Y134-K322 loop that connects TM3 and TM4, may proceed via the activation of a putative metallopeptidase. [less ▲]

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See detailPenicillin target enzyme and the antibiotic binding site
Kelly, Judith A.; Moews, Paul C.; Knox, James R. et al

in Science (1982), 218(4571), 479-481

The three-dimensional structure of a penicillin-sensitive D-alanyl-carboxypeptidase-transpeptidase has been determined by x-ray crystallography to a resolution of 2.8 angstroms. The site of binding of the ... [more ▼]

The three-dimensional structure of a penicillin-sensitive D-alanyl-carboxypeptidase-transpeptidase has been determined by x-ray crystallography to a resolution of 2.8 angstroms. The site of binding of the beta-lactam antibiotics penicillin and cephalosporin has been located. These findings constitute direct observation of the interaction of beta-lactams with a transpeptidase enzyme and establish the feasibility of defining the molecular stereochemistry of this interaction for purposes of drug design. [less ▲]

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See detailThe penicillin Target in Bacteria
Ghuysen, Jean-Marie ULg; Leyh-Bouille, Mélina; Frère, Jean-Marie ULg et al

in Spencer, B. (Ed.) Industrial Aspects of Biochemistry (FEBS Proceedings) (1974)

The bacterial target of beta-lactam antibiotics consists of a set of multiple, membrane-bound receptors. Some of them have been characterized as DD-carboxypeptidases. The DD-carboxypeptidases catalyse the ... [more ▼]

The bacterial target of beta-lactam antibiotics consists of a set of multiple, membrane-bound receptors. Some of them have been characterized as DD-carboxypeptidases. The DD-carboxypeptidases catalyse the opening of amide bonds and transfer the carbonyl carbon to an exogenous nucleophile, and are specifically designed to operate on the D-Ala-D-Ala linkageof L-R-D-Ala-D-Ala terminated peptides (where R is most often a diamino acid residue). The R61, R39 and several Bacilli DD-carboxypeptidases are known to be serine-enzymes and the G DD-carboxypeptidase has been characterized as a metallo (Zn ions) enzyme. Both the R61 and the G enzymes have been crystallized. In turn, the S. faecalis 43,000-Mr DD-carboxypeptidase, which is inhibited by low dose levels of pCMB, might be a thiol-enzyme. The goal pursued is the understanding of the mechanistic properties and functioning of the active centers of the DD-carboxypeptidases at the molecular and atomic levels. The research program involves 1) further characterization of the S. faecalis enzyme (which can be obtained in a water-soluble form); 2) isolation of various Streptomyces membrane-bound enzymes in a truly water-soluble form; 3) sequencing of the G and R61 enzymes; 4) the 2.8 A structure analysis of the G enzyme. (A similar study is conducted by Dr. J.R. Knox at the University of Connecticut, on the R61 enzyme, which enzyme is prepared and purified in this laboratory and then sent to Storrs); 5) conformational studies and quantitative structure activity relationships (QSAR). Source du résumé : http://www.researchcrossroads.org/index.php?view=article&id=50%3Agrant-details&option=com_content&Itemid=64&grant_id=4296130 [less ▲]

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See detailPENICILLIN-BINDING PROTEIN 2X OF STREPTOCOCCUS-PNEUMONIAE - ENZYMATIC-ACTIVITIES AND INTERACTIONS WITH BETA-LACTAMS
JAMIN, M.; Damblon, Christian ULg; MILLIER, S. et al

in Biochemical Journal (1993), 292(Part 3), 735-741

The high-molecular-mass penicillin-binding protein (PBP) 2x, one of the primary targets of beta-lactam antibiotics in Streptococcus pneumoniae, has been produced as a soluble form and purified in large ... [more ▼]

The high-molecular-mass penicillin-binding protein (PBP) 2x, one of the primary targets of beta-lactam antibiotics in Streptococcus pneumoniae, has been produced as a soluble form and purified in large amounts. It has been shown to catalyse hydrolysis and transfer reactions with different ester and thiolester substrates and its catalytic behaviour was often similar to that of the soluble DD-peptidase from Streptomyces R61. This provided an easy method to monitor the activity of the PBP. For the first time, a reliable kinetic study of the interaction between a lethal target and beta-lactam antibiotics has been performed. Characteristic kinetic parameters were obtained with different beta-lactam compounds. These results not only validated the mechanism established with non-essential extracellular enzymes, but will also constitute the basis for comparative studies of the low-affinity variants from penicillin-resistant strains. [less ▲]

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See detailPenicillin-binding proteins and carboxypeptidase/transpeptidase activities in Proteus vulgaris P18 and its penicillin-induced stable L-forms
Rousset, André; Nguyen-Distèche, Martine ULg; Minck, Raymond et al

in Journal of Bacteriology (1982), 152(3), 1042-1048

The originally penicillin-induced, wall-less stable L-forms of Proteus vulgaris P18, isolated by Tulasne in 1949 and since then cultured in he absence of penicillin, have kept the ability to synthesize ... [more ▼]

The originally penicillin-induced, wall-less stable L-forms of Proteus vulgaris P18, isolated by Tulasne in 1949 and since then cultured in he absence of penicillin, have kept the ability to synthesize the seven penicillin-binding proteins and the various DD- and LD-peptidase activities found in the parental bacteria and known to be involved in wall peptidoglycan metabolism. The stable L-forms, however, secrete during growth both the highly penicillin-sensitive, DD-carboxy-peptidase-transpeptidase penicillin-binding protein PBP4 (which in normal bacteria is relatively loosely bound to the plasma membrane) and the penicillin-insensitive LD-carboxypeptidase (which in normal bacteria is located in the periplasmic region). [less ▲]

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See detailThe penicillin-binding proteins in Streptococcus faecalis ATCC 9790
Coyette, Jean; Ghuysen, Jean-Marie ULg; Fontana, Roberta

in European Journal of Biochemistry (1980), 110(2), 445-456

Streptococcus faecalis ATCC 9790 possesses seven membrane-bound penicillin-binding proteins. They have been characterized with respect to their apparent molecular weights, relative abundance, specificity ... [more ▼]

Streptococcus faecalis ATCC 9790 possesses seven membrane-bound penicillin-binding proteins. They have been characterized with respect to their apparent molecular weights, relative abundance, specificity profiles for 15 different beta-lactam antibiotics and stability under various conditions. In water and at 37 degrees C, all the native penicillin-binding proteins have half-lives longer than 20 h except protein 3b (half-life of about 600 min) and protein 4 (half-life of about 175 min). The short-lived 80 000-Mr protein 4 is spontaneously converted into a 73 000-Mr water-soluble, penicillin-binding protein 4. Similarly, the short-lived 82 000-Mr protein 3b seems to be the protein from which the 72 000-Mr water-soluble protein X spontaneously originates during incubation of the membranes. Release of both proteins 4 and X from the membrane is maximal under alkaline conditions; it is not inhibited by various protease inhibitors. After exposure to trypsin, the 43 000-Mr membrane-bound penicillin binding protein 6 (a DD-carboxypeptidase) gives to a 30 000-Mr water-soluble protein 6. Like the parent protein, protein 6 exhibits both DD-carboxypeptidase activity and penicillin-binding ability. With proteins 6 and 6, low dose levels of p-chloromercuribenzoate prevent both enzyme activity and combination with penicillin, thus strongly suggesting that a thiol group is involved in the enzyme active center. We have shown previously [Coyette et al. in Eur. J. Biochem. 88, 297--305 (1978) and 75, 231--239 (1977)] that the DD-carboxypeptidase protein 6 fragments the benzylpenicillin molecule with formation of phenylacetylglycine. Breakdown of the complex formed between [14C]benzylpenicillin and 14 000-Mr membrane-bound protein 1 is also 'enzyme-catalysed'. Most likely, however, the released product is penicilloate. With all the other penicillin-binding proteins whose molecular weights are intermediate between those of proteins 1 and 6, breakdown of the complexes formed with [14C]benzylpenicillin results from proteolysis and is not due to the release of the bound metabolite. None of the penicillin-binding proteins behaves, by itself, as a lethal target for beta-lactam antibiotic action on the living cells. [less ▲]

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See detailPenicillin-binding proteins in the membranes of Streptomyces sp
Dusart, Jean; Leyh-Bouille, Mélina; Nguyen-Distèche, Martine ULg et al

in Archives Internationales de Physiologie et de Biochimie (1980, February 01), 88(1), 27-29

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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 detailThe Penicillin-Binding Proteins: Structure and Role in Peptidoglycan Biosynthesis
Sauvage, Eric ULg; Kerff, Frédéric ULg; Terrak, Mohammed ULg et al

in FEMS Microbiology Reviews (2008), 32(2), 234-58

Penicillin-binding proteins (PBPs) have been scrutinized for over 40 years. Recent structural information on PBPs together with the ongoing long-term biochemical experimental investigations, and results ... [more ▼]

Penicillin-binding proteins (PBPs) have been scrutinized for over 40 years. Recent structural information on PBPs together with the ongoing long-term biochemical experimental investigations, and results from more recent techniques such as protein localization by green fluorescent protein-fusion immunofluorescence or double-hybrid assay, have brought our understanding of the last stages of the peptidoglycan biosynthesis to an outstanding level that allows a broad outlook on the properties of these enzymes. Details are emerging regarding the interaction between the peptidoglycan-synthesizing PBPs and the peptidoglycan, their mesh net-like product that surrounds and protects bacteria. This review focuses on the detailed structure of PBPs and their implication in peptidoglycan synthesis, maturation and recycling. An overview of the content in PBPs of some bacteria is provided with an emphasis on comparing the biochemical properties of homologous PBPs (orthologues) belonging to different bacteria. [less ▲]

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See detailThe penicillin-binding site in the exocellular DD-carboxypeptidase-transpeptidase of Actinomadura R39
Duez, Colette ULg; Joris, Bernard ULg; Frère, Jean-Marie ULg et al

in Biochemical Journal (1981), 193

Heat denaturation and Pronase degradation of the complex previously formed between benzylpenicillin and the exocellular DD-carboxypeptidase-transpeptidase of Actinomadura R39 yields a heptapeptide H-Leu ... [more ▼]

Heat denaturation and Pronase degradation of the complex previously formed between benzylpenicillin and the exocellular DD-carboxypeptidase-transpeptidase of Actinomadura R39 yields a heptapeptide H-Leu-Pro-Ala-Ser-Asn-Gly-Val-OH, where the benzylpenicilloyl group is ester-linked to the serine residue. This linkage is very labile and its hydrolysis causes the release of benzylpenicilloate. In contrast, the native benzylpenicilloyl-enzyme complex is very stable (half-life 70h at 370C) and its breakdown proceeds via fragmentation of the bound benzylpenicilloyl group [Fuad, Frere, Ghuysen, Duez & Iwatsubo (1976) Biochem. J. 155, 623-6291. [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 detailPenicillin-sensitive DD-carboxypeptidase from Streptomyces strain R 61
Leyh-Bouille, Mélina; Coyette, Jacques; Ghuysen, Jean-Marie ULg et al

in Biochemistry (1971), 10(11), 2163-2170

The D-alanyl-D-alanine carboxypeptidase excreted by the penicillin-sensitive Streptomyces strain R 61 is an anionic protein at pH 6.5. It does not require cations for its action. By comparison with the ... [more ▼]

The D-alanyl-D-alanine carboxypeptidase excreted by the penicillin-sensitive Streptomyces strain R 61 is an anionic protein at pH 6.5. It does not require cations for its action. By comparison with the penicillin-resistant DD-carboxypeptidase from Streptomyces albus G, the penicillin-sensitive R 61 enzyme has high Km values with all the peptides which were used but the alignment of catalytic groups is more effective in promoting hydrolysis of the peptides (high Vmax values). Moreover, the substrate structures required by the two enzymes show some differences. In contrast to the albus G DD -carboxypeptidase which is either not, or very little, affected by penicillins, the R 61 enzyme is inhibited by low dose levels of penicillin G and by cephalothin [less ▲]

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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 ▲]

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See detailPenicillin-sensitive enzymes in peptidoglycan biosynthesis
Frère, Jean-Marie ULg; Joris, Bernard ULg

in CRC Critical Reviews in Microbiology (1985), 11

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See detailPenicillin-Sensitive Enzymes of Peptidoglycan Metabolism
Ghuysen, Jean-Marie ULg

in Critical Reviews in Microbiology (1977)

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See detailPenicillins and Δ3-cephalosporins as inhibitors and mechanism-based inactivators of D-alanyl-D-Ala peptidases
Ghuysen, Jean-Marie ULg; Frère, Jean-Marie ULg; Leyh-Bouille, Mélina et al

in Burgen, A. S. V.; Roberts, G. C. K. (Eds.) Topics in molecular pharmacology (1981)

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See detailPenile aneurysmal bone cyst causing urethral obstruction in a dog
Saulnier-Troff, François-Guillaume; Busoni, Valeria ULg; Hamaide, Annick ULg

Poster (2008, July)

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See detailPenile Prosthesis in the Age of the Blue Pill
Andrianne, Robert ULg

in Acta Chirurgica Belgica (2010), (110), 149-152

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See detailPenile prosthesis, sexual satisfaction and representation of male erotic value
Kempeneers, Philippe ULg; Andrianne, Robert ULg; Mormont, Christian ULg

in Sexual & Relationship Therapy (2004), 19(4),

A follow-up study conducted among 39 implanted patients and 30 partners shows that subjects' satisfaction towards prosthetic-sexulaity depends on their representation of male erotic value. The less ... [more ▼]

A follow-up study conducted among 39 implanted patients and 30 partners shows that subjects' satisfaction towards prosthetic-sexulaity depends on their representation of male erotic value. The less satisfied patients are sensitive to a normative representation that associates erotic value to criteria of "sponataneity", "naturalness", "tall an non-assisted erections". Their main dissatisfaction likely derives from the insufficiency of a prosthetic solution to restore a male self-image based on such criteria. This induces a more important impact on satisfaction rates than do functional problems (e.g. difficulties in manipulating the device, unwanted deflations, uncomfortable sensations). These patients also show an attribution bias consisting in attributing erroneously the same dissatisfaction and negative attitude towards prosthetic sexuality to their partner. Therfore, in addition to surgery, a psychosexual support is necessary to modify erotic representations and to improve the communication between the partners in order to increase sexual satisfaction with prosthesis-assisted sexuality [less ▲]

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