Interplay between Penicillin-binding proteins and SEDS proteins promotes bacterial cell wall synthesis.
Leclercq, Sophie ; Derouaux, Adeline ; Olatunji, Samir et al
in Scientific Reports (2017), 7
Bacteria utilize specialized multi-protein machineries to synthesize the essential peptidoglycan (PG) cell wall during growth and division. The divisome controls septal PG synthesis and separation of ... [more ▼]
Bacteria utilize specialized multi-protein machineries to synthesize the essential peptidoglycan (PG) cell wall during growth and division. The divisome controls septal PG synthesis and separation of daughter cells. In E. coli, the lipid II transporter candidate FtsW is thought to work in concert with the PG synthases penicillin-binding proteins PBP3 and PBP1b. Yet, the exact molecular mechanisms of their function in complexes are largely unknown. We show that FtsW interacts with PBP1b and lipid II and that PBP1b, FtsW and PBP3 co-purify suggesting that they form a trimeric complex. We also show that the large loop between transmembrane helices 7 and 8 of FtsW is important for the interaction with PBP3. Moreover, we found that FtsW, but not the other flippase candidate MurJ, impairs lipid II polymerization and peptide cross-linking activities of PBP1b, and that PBP3 relieves these inhibitory effects. All together the results suggest that FtsW interacts with lipid II preventing its polymerization by PBP1b unless PBP3 is also present, indicating that PBP3 facilitates lipid II release and/or its transfer to PBP1b after transport across the cytoplasmic membrane. This tight regulatory mechanism is consistent with the cell's need to ensure appropriate use of the limited pool of lipid II. [less ▲]Detailed reference viewed: 13 (6 ULg)
Glycosyltransferases and Transpeptidases/Penicillin-Binding Proteins: Valuable Targets for New Antibacterials.
Sauvage, Eric ; Terrak, Mohammed
in Antibiotics (2016), 5(1),
Peptidoglycan (PG) is an essential macromolecular sacculus surrounding most bacteria. It is assembled by the glycosyltransferase (GT) and transpeptidase (TP) activities of multimodular penicillin-binding ... [more ▼]
Peptidoglycan (PG) is an essential macromolecular sacculus surrounding most bacteria. It is assembled by the glycosyltransferase (GT) and transpeptidase (TP) activities of multimodular penicillin-binding proteins (PBPs) within multiprotein complex machineries. Both activities are essential for the synthesis of a functional stress-bearing PG shell. Although good progress has been made in terms of the functional and structural understanding of GT, finding a clinically useful antibiotic against them has been challenging until now. In contrast, the TP/PBP module has been successfully targeted by beta-lactam derivatives, but the extensive use of these antibiotics has selected resistant bacterial strains that employ a wide variety of mechanisms to escape the lethal action of these antibiotics. In addition to traditional beta-lactams, other classes of molecules (non-beta-lactams) that inhibit PBPs are now emerging, opening new perspectives for tackling the resistance problem while taking advantage of these valuable targets, for which a wealth of structural and functional knowledge has been accumulated. The overall evidence shows that PBPs are part of multiprotein machineries whose activities are modulated by cofactors. Perturbation of these systems could lead to lethal effects. Developing screening strategies to take advantage of these mechanisms could lead to new inhibitors of PG assembly. In this paper, we present a general background on the GTs and TPs/PBPs, a survey of recent issues of bacterial resistance and a review of recent works describing new inhibitors of these enzymes. [less ▲]Detailed reference viewed: 18 (2 ULg)
Structure-Activity Relationships of Novel Tryptamine-Based Inhibitors of Bacterial Transglycosylase.
; ; et al
in Journal of medicinal chemistry (2015)
Penicillin-binding proteins represent well-established, validated, and still very promising targets for the design and development of new antibacterial agents. The transglycosylase domain of penicillin ... [more ▼]
Penicillin-binding proteins represent well-established, validated, and still very promising targets for the design and development of new antibacterial agents. The transglycosylase domain of penicillin-binding proteins is especially important, as it catalyzes polymerization of glycan chains, using the peptidoglycan precursor lipid II as a substrate. On the basis of the previous discovery of a noncovalent small-molecule inhibitor of transglycosylase activity, we systematically explored the structure-activity relationships of these tryptamine-based inhibitors. The main aim was to reduce the nonspecific cytotoxic properties of the initial hit compound and concurrently to retain the mode of its inhibition. A focused library of tryptamine-based compounds was synthesized, characterized, and evaluated biochemically. The results presented here show the successful reduction of the nonspecific cytotoxicity, and the retention of the inhibition of transglycosylase enzymatic activity, as well as the ability of these compounds to bind to lipid II and to have antibacterial actions. [less ▲]Detailed reference viewed: 36 (5 ULg)
In vitro reconstitution of multi-proteins complexes of the peptidoglycan synthesis machinery of Escherichia coli
; Olatunji, Samir ; Derouaux, Adeline et al
Poster (2015, September)Detailed reference viewed: 37 (2 ULg)
Electron paramagnetic resonance and fluorescence studies on potential anticancer properties of two new Ru(II) complexes : preliminary results
Collienne, Simon ; Terrak, Mohammed ; Mouithys-Mickalad, Ange et al
Poster (2015, May 22)
Fight against cancer is a priority of today’s research. Since the discovery of the anticancer properties of cisplatin (CisPt) in 1965 by Rosenberg , the treatment of cancer by chemotherapy has known ... [more ▼]
Fight against cancer is a priority of today’s research. Since the discovery of the anticancer properties of cisplatin (CisPt) in 1965 by Rosenberg , the treatment of cancer by chemotherapy has known great improvements. Unfortunately, CisPt has several side effects and is not effective against all kinds of cancer. Nevertheless its use highlights the great potential of organometallic compounds in the treatment of cancer . Here we investigated the potential anticancer properties of two new organometallic compounds based on ruthenium II : [RuCl(p-cymene)(S2C.IDip)]+(PF6)- and [RuCl(p-cymene)(S2C.ICy)]+(PF6)-, named as LDO436 and LDO437 respectively. [less ▲]Detailed reference viewed: 87 (30 ULg)
Positive cooperativity between acceptor and donor sites of the peptidoglycan glycosyltransferase.
; Dahmane, Ismahene ; Derouaux, Adeline et al
in Biochemical pharmacology (2015), 93(2), 141-50
The glycosyltransferases of family 51 (GT51) catalyze the polymerization of lipid II to form linear glycan chains, which, after cross linking by the transpeptidases, form the net-like peptidoglycan ... [more ▼]
The glycosyltransferases of family 51 (GT51) catalyze the polymerization of lipid II to form linear glycan chains, which, after cross linking by the transpeptidases, form the net-like peptidoglycan macromolecule. The essential function of the GT makes it an attractive antimicrobial target; therefore a better understanding of its function and its mechanism of interaction with substrates could help in the design and the development of new antibiotics. In this work, we have used a surface plasmon resonance Biacore((R)) biosensor, based on an amine derivative of moenomycin A immobilized on a sensor chip surface, to investigate the mechanism of binding of substrate analogous inhibitors to the GT. Addition of increasing concentrations of moenomycin A to the Staphylococcus aureus MtgA led to reduced binding of the protein to the sensor chip as expected. Remarkably, in the presence of low concentrations of the most active disaccharide inhibitors, binding of MtgA to immobilized moenomycin A was found to increase; in contrast competition with moenomycin A occurred only at high concentrations. This finding suggests that at low concentrations, the lipid II analogs bind to the acceptor site and induce a cooperative binding of moenomycin A to the donor site. Our results constitute the first indication of the existence of a positive cooperativity between the acceptor and the donor sites of peptidoglycan GTs. In addition, our study indicates that a modification of two residues (L119N and F120S) within the hydrophobic region of MtgA can yield monodisperse forms of the protein with apparently no change in its secondary structure content, but this is at the expense of the enzyme function. [less ▲]Detailed reference viewed: 100 (18 ULg)
Study of the activities of PBP3/PBP1b from Escherichia coli and the effect of the immediate divisome partners.
; Derouaux, Adeline ; Terrak, Mohammed
Poster (2013, September 23)Detailed reference viewed: 18 (10 ULg)
The crystal structure of the cell division amidase AmiC reveals the fold of the AMIN domain, a new peptidoglycan binding domain.
; Herman, Raphaël ; Sauvage, Eric et al
in Molecular microbiology (2013)
Binary fission is the ultimate step of the prokaryotic cell cycle. In Gram-negative bacteria like Escherichia coli, this step implies the invagination of three biological layers (cytoplasmic membrane ... [more ▼]
Binary fission is the ultimate step of the prokaryotic cell cycle. In Gram-negative bacteria like Escherichia coli, this step implies the invagination of three biological layers (cytoplasmic membrane, peptidoglycan and outer membrane), biosynthesis of the new poles and eventually, daughter cells separation. The latter requires the coordinated action of the N-acetylmuramyl-L-alanine amidases AmiA/B/C and their LytM activators EnvC and NlpD to cleave the septal peptidoglycan. We present here the 2.5 A crystal structure of AmiC which includes the first report of an AMIN domain structure, a beta-sandwich of two symmetrical four-stranded beta-sheets exposing highly conserved motifs on the two outer faces. We show that this N-terminal domain, involved in the localization of AmiC at the division site, is a new peptidoglycan-binding domain. The C-terminal catalytic domain shows an auto-inhibitory alpha helix obstructing the active site. AmiC lacking this helix exhibits by itself an activity comparable to that of the wild type AmiC activated by NlpD. We also demonstrate the interaction between AmiC and NlpD by microscale thermophoresis and confirm the importance of the active site blocking alpha helix in the regulation of the amidase activity. [less ▲]Detailed reference viewed: 32 (11 ULg)
Characterization of amylolysin, a novel lantibiotic from Bacillus amyloliquefaciens GA1
Arguelles Arias, Anthony ; Ongena, Marc ; et al
in PLoS ONE (2013), 8(12),
Background: Lantibiotics are heat-stable peptides characterized by the presence of thioether amino acid lanthionine and methyllanthionine. They are capable to inhibit the growth of Gram-positive bacteria ... [more ▼]
Background: Lantibiotics are heat-stable peptides characterized by the presence of thioether amino acid lanthionine and methyllanthionine. They are capable to inhibit the growth of Gram-positive bacteria, including Listeria monocytogenes, Staphylococcus aureus or Bacillus cereus, the causative agents of food-borne diseases or nosocomial infections. Lantibiotic biosynthetic machinery is encoded by gene cluster composed by a structural gene that codes for a pre-lantibiotic peptide and other genes involved in pre-lantibiotic modifications, regulation, export and immunity. Methodology/Findings: Bacillus amyloliquefaciens GA1 was found to produce an antimicrobial peptide, named amylolysin, active on an array of Gram-positive bacteria, including methicillin resistant S. aureus. Genome characterization led to the identification of a putative lantibiotic gene cluster that comprises a structural gene (amlA) and genes involved in modification (amlM), transport (amlT), regulation (amlKR) and immunity (amlFE). Disruption of amlA led to loss of biological activity, confirming thus that the identified gene cluster is related to amylolysin synthesis. MALDI-TOF and LC-MS analysis on purified amylolysin demonstrated that this latter corresponds to a novel lantibiotic not described to date. The ability of amylolysin to interact in vitro with the lipid II, the carrier of peptidoglycan monomers across the cytoplasmic membrane and the presence of a unique modification gene suggest that the identified peptide belongs to the group B lantibiotic. Amylolysin immunity seems to be driven by only two AmlF and AmlE proteins, which is uncommon within the Bacillus genus. Conclusion/Significance: Apart from mersacidin produced by Bacillus amyloliquefaciens strains Y2 and HIL Y-85,544728, reports on the synthesis of type B-lantibiotic in this species are scarce. This study reports on a genetic and structural characterization of another representative of the type B lantibiotic in B. amyloliquefaciens. Copyright: © 2013 Arguelles Arias et al. [less ▲]Detailed reference viewed: 55 (21 ULg)
Peptidoglycan glycosyltransferase substrate mimics as templates for the design of new antibacterial drugs.
Derouaux, Adeline ; Sauvage, Eric ; Terrak, Mohammed
in Frontiers in immunology (2013), 4
Peptidoglycan (PG) is an essential net-like macromolecule that surrounds bacteria, gives them their shape, and protects them against their own high osmotic pressure. PG synthesis inhibition leads to ... [more ▼]
Peptidoglycan (PG) is an essential net-like macromolecule that surrounds bacteria, gives them their shape, and protects them against their own high osmotic pressure. PG synthesis inhibition leads to bacterial cell lysis, making it an important target for many antibiotics. The final two reactions in PG synthesis are performed by penicillin-binding proteins (PBPs). Their glycosyltransferase (GT) activity uses the lipid II precursor to synthesize glycan chains and their transpeptidase (TP) activity catalyzes the cross-linking of two glycan chains via the peptide side chains. Inhibition of either of these two reactions leads to bacterial cell death. beta-lactam antibiotics target the transpeptidation reaction while antibiotic therapy based on inhibition of the GTs remains to be developed. Ongoing research is trying to fill this gap by studying the interactions of GTs with inhibitors and substrate mimics and utilizing the latter as templates for the design of new antibiotics. In this review we present an updated overview on the GTs and describe the structure-activity relationship of recently developed synthetic ligands. [less ▲]Detailed reference viewed: 32 (5 ULg)
Structure of the E. coli amidase AmiC and its activation by the LytM cofactor NlpD
Kerff, Frédéric ; Rocaboy, Mathieu ; Herman, Raphaël et al
Poster (2012, June 25)Detailed reference viewed: 36 (9 ULg)
Synthesis of Modified Peptidoglycan Precursor Analogues for the Inhibition of Glycosyltransferase.
; Derouaux, Adeline ; et al
in Journal of the American Chemical Society (2012)
The peptidoglycan glycosyltransferases (GTs) are essential enzymes that catalyze the polymerization of glycan chains of the bacterial cell wall from lipid II and thus constitute a validated antibacterial ... [more ▼]
The peptidoglycan glycosyltransferases (GTs) are essential enzymes that catalyze the polymerization of glycan chains of the bacterial cell wall from lipid II and thus constitute a validated antibacterial target. Their enzymatic cavity is composed of a donor site for the growing glycan chain (where the inhibitor moenomycin binds) and an acceptor site for lipid II substrate. In order to find lead inhibitors able to fill this large active site, we have synthesized a series of substrate analogues of lipid I and lipid II with variations in the lipid, the pyrophosphate, and the peptide moieties and evaluated their biological effect on the GT activity of E. coli PBP1b and their antibacterial potential. We found several compounds able to inhibit the GT activity in vitro and cause growth defect in Bacillus subtilis . The more active was C16-phosphoglycerate-MurNAc-(l-Ala-d-Glu)-GlcNAc, which also showed antibacterial activity. These molecules are promising leads for the design of new antibacterial GT inhibitors. [less ▲]Detailed reference viewed: 37 (6 ULg)
Cooperativity of peptidoglycan synthases active in bacterial cell elongation.
; ; Terrak, Mohammed et al
in Molecular Microbiology (2012), 85(1), 179-94
Growth of the bacterial cell wall peptidoglycan sacculus requires the co-ordinated activities of peptidoglycan synthases, hydrolases and cell morphogenesis proteins, but the details of these interactions ... [more ▼]
Growth of the bacterial cell wall peptidoglycan sacculus requires the co-ordinated activities of peptidoglycan synthases, hydrolases and cell morphogenesis proteins, but the details of these interactions are largely unknown. We now show that the Escherichia coli peptidoglycan glycosyltrasferase-transpeptidase PBP1A interacts with the cell elongation-specific transpeptidase PBP2 in vitro and in the cell. Cells lacking PBP1A are thinner and initiate cell division later in the cell cycle. PBP1A localizes mainly to the cylindrical wall of the cell, supporting its role in cell elongation. Our in vitro peptidoglycan synthesis assays provide novel insights into the cooperativity of peptidoglycan synthases with different activities. PBP2 stimulates the glycosyltransferase activity of PBP1A, and PBP1A and PBP2 cooperate to attach newly synthesized peptidoglycan to sacculi. PBP2 has peptidoglycan transpeptidase activity in the presence of active PBP1A. Our data also provide a possible explanation for the depletion of lipid II precursors in penicillin-treated cells. [less ▲]Detailed reference viewed: 14 (0 ULg)
Specificity of E. coli PBP1b for the substrate and inhibition of its GT activity.
Terrak, Mohammed ; ;
Conference (2011, September 29)Detailed reference viewed: 15 (4 ULg)
Tryptamine-derived compounds as antibacterial agents.
Terrak, Mohammed ; ; et al
Patent (2011)Detailed reference viewed: 27 (1 ULg)
Small molecule inhibitors of peptidoglycan synthesis targeting the lipid II precursor.
Derouaux, Adeline ; ; et al
in Biochemical Pharmacology (2011), 81(9), 1098-105
Bacterial peptidoglycan glycosyltransferases (GTs) of family 51 catalyze the polymerization of the lipid II precursor into linear peptidoglycan strands. This activity is essential to bacteria and ... [more ▼]
Bacterial peptidoglycan glycosyltransferases (GTs) of family 51 catalyze the polymerization of the lipid II precursor into linear peptidoglycan strands. This activity is essential to bacteria and represents a validated target for the development of new antibacterials. Application of structure-based virtual screening to the National Cancer Institute library using eHits program and the structure of the glycosyltransferase domain of the Staphylococcus aureus penicillin-binding protein 2 resulted in the identification of two small molecules analogues 5, a 2-[1-[(2-chlorophenyl)methyl]-2-methyl-5-methylsulfanylindol-3-yl]ethanamine and 5b, a 2-[1-[(3,4-dichlorophenyl)methyl]-2-methyl-5-methylsulfanylindol-3-yl]ethanamine that exhibit antibacterial activity against several Gram-positive bacteria but were less active on Gram-negative bacteria. The two compounds inhibit the activity of five GTs in the micromolar range. Investigation of the mechanism of action shows that the compounds specifically target peptidoglycan synthesis. Unexpectedly, despite the fact that the compounds were predicted to bind to the GT active site, compound 5b was found to interact with the lipid II substrate via the pyrophosphate motif. In addition, this compound showed a negatively charged phospholipid-dependent membrane depolarization and disruption activity. These small molecules are promising leads for the development of more active and specific compounds to target the essential GT step in cell wall synthesis. [less ▲]Detailed reference viewed: 89 (15 ULg)
Monofunctional transglycosylases are not essential for Staphylococcus aureus cell wall synthesis.
; ; et al
in Journal of Bacteriology (2011), 193(10), 2549-56
The polymerization of peptidoglycan is the result of two types of enzymatic activities: transglycosylation, the formation of linear glycan chains, and transpeptidation, the formation of peptide cross ... [more ▼]
The polymerization of peptidoglycan is the result of two types of enzymatic activities: transglycosylation, the formation of linear glycan chains, and transpeptidation, the formation of peptide cross-bridges between the glycan strands. Staphylococcus aureus has four penicillin binding proteins (PBP1 to PBP4) with transpeptidation activity, one of which, PBP2, is a bifunctional enzyme that is also capable of catalyzing transglycosylation reactions. Additionally, two monofunctional transglycosylases have been reported in S. aureus: MGT, which has been shown to have in vitro transglycosylase activity, and a second putative transglycosylase, SgtA, identified only by sequence analysis. We have now shown that purified SgtA has in vitro transglycosylase activity and that both MGT and SgtA are not essential in S. aureus. However, in the absence of PBP2 transglycosylase activity, MGT but not SgtA becomes essential for cell viability. This indicates that S. aureus cells require one transglycosylase for survival, either PBP2 or MGT, both of which can act as the sole synthetic transglycosylase for cell wall synthesis. We have also shown that both MGT and SgtA interact with PBP2 and other enzymes involved in cell wall synthesis in a bacterial two-hybrid assay, suggesting that these enzymes may work in collaboration as part of a larger, as-yet-uncharacterized cell wall-synthetic complex. [less ▲]Detailed reference viewed: 43 (18 ULg)
Optimization of conditions for the glycosyltransferase activity of penicillin-binding protein 1a from Thermotoga maritima.
; Terrak, Mohammed ; Derouaux, Adeline et al
in FEBS Journal (2010), 277(20), 4290-8
Cell wall biosynthesis is a key target for antibacterial drugs. The major constituent of the bacterial wall, peptidoglycan, is a netlike polymer responsible for the size and shape of the cell and for ... [more ▼]
Cell wall biosynthesis is a key target for antibacterial drugs. The major constituent of the bacterial wall, peptidoglycan, is a netlike polymer responsible for the size and shape of the cell and for resisting osmotic pressure. It consists of glycan chains of repeating disaccharide units cross-linked through short peptide chains. Peptidoglycan assembly is catalyzed by the periplasmic domain of bifunctional class A penicillin-binding proteins. Cross-linking of the peptide chains is catalyzed by their transpeptidase module, which can be inhibited by the most widely used antibiotics, the beta-lactams. In contrast, no drug in clinical use inhibits the polymerization of the glycan chains, catalyzed by their glycosyltransferase module, although it is an obvious target. We report here the purification of the ectodomain of the class A penicillin-binding protein 1a from Thermotoga maritima (Tm-1a*), expressed recombinantly in Escherichia coli. A detergent screen showed that detergents with shorter aliphatic chains were better solubilizers. Cyclohexyl-hexyl-beta-D-maltoside-purified Tm-1a* was found to be monomeric and to have improved thermal stability. A miniaturized, multiwell continuous fluorescence assay of the glycosyltransferase activity was used to screen for optimal reaction conditions. Tm-1a* was active as a glycosyltransferase, catalyzing the formation of glycan chains up to 16 disaccharide units long. Our results emphasize the importance of the detergent in preparing a stable monomeric ectodomain of a class A penicillin-binding protein. Our assay could be used to screen collections of compounds for inhibitors of peptidoglycan glycosyltransferases that could serve as the basis for the development of novel antibiotics. [less ▲]Detailed reference viewed: 38 (13 ULg)
Identification and characterization of novel peptidoglycan glycosyltransferase inhibitors with antibacterial activity
Derouaux, Adeline ; ; et al
Poster (2009, November)Detailed reference viewed: 28 (3 ULg)