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Brötz-Oesterhelt H, Vorbach A. Reprogramming of the Caseinolytic Protease by ADEP Antibiotics: Molecular Mechanism, Cellular Consequences, Therapeutic Potential. Front Mol Biosci 2021; 8:690902. [PMID: 34109219 PMCID: PMC8182300 DOI: 10.3389/fmolb.2021.690902] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2021] [Accepted: 04/28/2021] [Indexed: 12/14/2022] Open
Abstract
Rising antibiotic resistance urgently calls for the discovery and evaluation of novel antibiotic classes and unique antibiotic targets. The caseinolytic protease Clp emerged as an unprecedented target for antibiotic therapy 15 years ago when it was observed that natural product-derived acyldepsipeptide antibiotics (ADEP) dysregulated its proteolytic core ClpP towards destructive proteolysis in bacterial cells. A substantial database has accumulated since on the interaction of ADEP with ClpP, which is comprehensively compiled in this review. On the molecular level, we describe the conformational control that ADEP exerts over ClpP, the nature of the protein substrates degraded, and the emerging structure-activity-relationship of the ADEP compound class. On the physiological level, we review the multi-faceted antibacterial mechanism, species-dependent killing modes, the activity against carcinogenic cells, and the therapeutic potential of the compound class.
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Affiliation(s)
- Heike Brötz-Oesterhelt
- Microbial Bioactive Compounds, Interfaculty Institute of Microbiology and Infection Medicine, University of Tuebingen, Tübingen, Germany.,Cluster of Excellence: Controlling Microbes to Fight Infection, Tübingen, Germany
| | - Andreas Vorbach
- Microbial Bioactive Compounds, Interfaculty Institute of Microbiology and Infection Medicine, University of Tuebingen, Tübingen, Germany
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Silber N, Matos de Opitz CL, Mayer C, Sass P. Cell division protein FtsZ: from structure and mechanism to antibiotic target. Future Microbiol 2020; 15:801-831. [DOI: 10.2217/fmb-2019-0348] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Antimicrobial resistance to virtually all clinically applied antibiotic classes severely limits the available options to treat bacterial infections. Hence, there is an urgent need to develop and evaluate new antibiotics and targets with resistance-breaking properties. Bacterial cell division has emerged as a new antibiotic target pathway to counteract multidrug-resistant pathogens. New approaches in antibiotic discovery and bacterial cell biology helped to identify compounds that either directly interact with the major cell division protein FtsZ, thereby perturbing the function and dynamics of the cell division machinery, or affect the structural integrity of FtsZ by inducing its degradation. The impressive antimicrobial activities and resistance-breaking properties of certain compounds validate the inhibition of bacterial cell division as a promising strategy for antibiotic intervention.
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Affiliation(s)
- Nadine Silber
- Department of Microbial Bioactive Compounds, Interfaculty Institute of Microbiology & Infection Medicine, University of Tübingen, Auf der Morgenstelle 28, Tübingen 72076, Germany
| | - Cruz L Matos de Opitz
- Department of Microbial Bioactive Compounds, Interfaculty Institute of Microbiology & Infection Medicine, University of Tübingen, Auf der Morgenstelle 28, Tübingen 72076, Germany
| | - Christian Mayer
- Department of Microbial Bioactive Compounds, Interfaculty Institute of Microbiology & Infection Medicine, University of Tübingen, Auf der Morgenstelle 28, Tübingen 72076, Germany
| | - Peter Sass
- Department of Microbial Bioactive Compounds, Interfaculty Institute of Microbiology & Infection Medicine, University of Tübingen, Auf der Morgenstelle 28, Tübingen 72076, Germany
- German Center for Infection Research (DZIF), partner site Tübingen, Tübingen 72076, Germany
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The ADEP Biosynthetic Gene Cluster in Streptomyces hawaiiensis NRRL 15010 Reveals an Accessory clpP Gene as a Novel Antibiotic Resistance Factor. Appl Environ Microbiol 2019; 85:AEM.01292-19. [PMID: 31399403 DOI: 10.1128/aem.01292-19] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Accepted: 08/02/2019] [Indexed: 02/06/2023] Open
Abstract
The increasing threat posed by multiresistant bacterial pathogens necessitates the discovery of novel antibacterials with unprecedented modes of action. ADEP1, a natural compound produced by Streptomyces hawaiiensis NRRL 15010, is the prototype for a new class of acyldepsipeptide (ADEP) antibiotics. ADEP antibiotics deregulate the proteolytic core ClpP of the bacterial caseinolytic protease, thereby exhibiting potent antibacterial activity against Gram-positive bacteria, including multiresistant pathogens. ADEP1 and derivatives, here collectively called ADEP, have been previously investigated for their antibiotic potency against different species, structure-activity relationship, and mechanism of action; however, knowledge on the biosynthesis of the natural compound and producer self-resistance have remained elusive. In this study, we identified and analyzed the ADEP biosynthetic gene cluster in S. hawaiiensis NRRL 15010, which comprises two NRPSs, genes necessary for the biosynthesis of (4S,2R)-4-methylproline, and a type II polyketide synthase (PKS) for the assembly of highly reduced polyenes. While no resistance factor could be identified within the gene cluster itself, we discovered an additional clpP homologous gene (named clpP ADEP) located further downstream of the biosynthetic genes, separated from the biosynthetic gene cluster by several transposable elements. Heterologous expression of ClpPADEP in three ADEP-sensitive Streptomyces species proved its role in conferring ADEP resistance, thereby revealing a novel type of antibiotic resistance determinant.IMPORTANCE Antibiotic acyldepsipeptides (ADEPs) represent a promising new class of potent antibiotics and, at the same time, are valuable tools to study the molecular functioning of their target, ClpP, the proteolytic core of the bacterial caseinolytic protease. Here, we present a straightforward purification procedure for ADEP1 that yields substantial amounts of the pure compound in a time- and cost-efficient manner, which is a prerequisite to conveniently study the antimicrobial effects of ADEP and the operating mode of bacterial ClpP machineries in diverse bacteria. Identification and characterization of the ADEP biosynthetic gene cluster in Streptomyces hawaiiensis NRRL 15010 enables future bioinformatics screenings for similar gene clusters and/or subclusters to find novel natural compounds with specific substructures. Most strikingly, we identified a cluster-associated clpP homolog (named clpP ADEP) as an ADEP resistance gene. ClpPADEP constitutes a novel bacterial resistance factor that alone is necessary and sufficient to confer high-level ADEP resistance to Streptomyces across species.
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Mukherjee S, Joardar N, Mondal S, Schiefer A, Hoerauf A, Pfarr K, Babu SPS. Quinolone-fused cyclic sulfonamide as a novel benign antifilarial agent. Sci Rep 2018; 8:12073. [PMID: 30104608 PMCID: PMC6089915 DOI: 10.1038/s41598-018-30610-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Accepted: 07/31/2018] [Indexed: 01/02/2023] Open
Abstract
Search of potent antifilarial drugs has been a major thrust area in tropical medicine research over the decades. Herein, we report 4,7-dimethyl-3,4,7,8-tetrahydro-3λ6-[1,2]thiazino[4,3-f]quinoline-3,3,8-trione (8l) as a new class of antifilarial agent which is extremely potent, with lethality against all the developmental stages (oocyte, microfilaria and adult) of the filarial parasite Setaria cervi. Molecular investigation on its mode of action revealed that 8l is a typical inducer of reactive oxygen species that triggers oxidative stress inside the filarid and further signals induction of apoptosis by activating both intrinsic and extrinsic pathways. Moreover, 8l is also active against Wolbachia, the essential endosymbiont of several human infectious filarids. Selective toxicity against filarial parasites and non-toxic nature in rat model were found as unique traits of 8l to be a future medicine. Taken en masse, this maiden report on a novel quinolone fused cyclic sulfonamide presents a promising therapeutic lead for lymphatic filariasis in future.
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Malik IT, Brötz-Oesterhelt H. Conformational control of the bacterial Clp protease by natural product antibiotics. Nat Prod Rep 2017; 34:815-831. [DOI: 10.1039/c6np00125d] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Natural products targeting the bacterial Clp protease unravel key interfaces for protein–protein–interaction and long-distance conformational control.
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Affiliation(s)
- I. T. Malik
- Department of Microbial Bioactive Compounds
- Interfaculty Institute of Microbiology and Infection Medicine
- University of Tuebingen
- Germany
| | - H. Brötz-Oesterhelt
- Department of Microbial Bioactive Compounds
- Interfaculty Institute of Microbiology and Infection Medicine
- University of Tuebingen
- Germany
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Gil F, Paredes-Sabja D. Acyldepsipeptide antibiotics as a potential therapeutic agent against Clostridium difficile recurrent infections. Future Microbiol 2016; 11:1179-89. [DOI: 10.2217/fmb-2016-0064] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Alternative antimicrobial therapies based on acyldepsipeptides may hold promising results, based on the fact that they have shown to efficiently eradicate persister cells, stationary cells and cell in biofilm structures of several pathogenic bacteria from the infected host. Clostridium difficile infection is considered the result of extensive hospital use of expanded-spectrum antibiotics, which cause dysbiosis of the intestinal microbiota, enhancing susceptibility to infection and persistence. Considering the urgent need for the development of novel and efficient antimicrobial strategies against C. difficile, we review the potential application to treat C. difficile infections of acyldepsipeptides family of antibiotics, its mechanism of action and current developmental stages.
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Affiliation(s)
- Fernando Gil
- Microbiota–Host Interactions & Clostridia Research Group, Departamento de Ciencias Biológicas, Facultad de Ciencias Biológicas, Universidad Andres Bello, Santiago, Chile
| | - Daniel Paredes-Sabja
- Microbiota–Host Interactions & Clostridia Research Group, Departamento de Ciencias Biológicas, Facultad de Ciencias Biológicas, Universidad Andres Bello, Santiago, Chile
- Center for Bioinformatic & Integrative Biology, Facultad de Ciencias Biológicas, Universidad Andres Bello, Santiago, Chile
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Nag JK, Chahar D, Shrivastava N, Gupta CL, Bajpai P, Chandra D, Misra-Bhattacharya S. Functional attributes of evolutionary conserved Arg45 of Wolbachia (Brugia malayi) translation initiation factor-1. Future Microbiol 2016; 11:195-214. [PMID: 26855259 DOI: 10.2217/fmb.15.135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
AIM Wolbachia is a promising antifilarial chemotherapeutic target. Translation initiation factor-1 (Tl IF-1) is an essential factor in prokaryotes. Functional characterization of Wolbachia's novel proteins/enzymes is necessary for the development of adulticidal drugs. MATERIALS & METHODS Mutant, Wol Tl IF-1 R45D was constructed by site directed mutagenesis. Fluorimetry and size exclusion chromatography were used to determine the biophysical characteristics. Mobility shift assay and fluorescence resonance energy transfer were used to investigate the functional aspect of Wol Tl IF-1 with its mutant. RESULTS Both wild and mutant were in monomeric native conformations. Wild exhibits nonspecific binding with ssRNA/ssDNA fragments under electrostatic conditions and showed annealing and displacement of RNA strands in comparison to mutant. CONCLUSION Point mutation impaired RNA chaperone activity of the mutant and its interaction with nucleotides.
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Affiliation(s)
- Jeetendra Kumar Nag
- Division of Parasitology, CSIR-Central Drug Research Institute, BS 10/1, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow (UP) 226031, India.,Department of Biochemistry, Lucknow University, Lucknow (UP) 226007, India
| | - Dhanvantri Chahar
- Division of Parasitology, CSIR-Central Drug Research Institute, BS 10/1, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow (UP) 226031, India.,Academy of Scientific & Innovative Research, Coordination Office, Mathura Road, CRRI, Jasola, New Delhi 110020, India
| | - Nidhi Shrivastava
- Division of Parasitology, CSIR-Central Drug Research Institute, BS 10/1, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow (UP) 226031, India
| | - Chhedi Lal Gupta
- Department of Biosciences, Integral University, Lucknow (UP) 226026, India
| | - Preeti Bajpai
- Department of Biosciences, Integral University, Lucknow (UP) 226026, India
| | - Deepak Chandra
- Department of Biochemistry, Lucknow University, Lucknow (UP) 226007, India
| | - Shailja Misra-Bhattacharya
- Division of Parasitology, CSIR-Central Drug Research Institute, BS 10/1, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow (UP) 226031, India.,Academy of Scientific & Innovative Research, Coordination Office, Mathura Road, CRRI, Jasola, New Delhi 110020, India
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Pseudomonas aeruginosa Lon and ClpXP proteases: roles in linking carbon catabolite repression system with quorum-sensing system. Curr Genet 2015; 62:1-6. [PMID: 26045103 DOI: 10.1007/s00294-015-0499-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Revised: 05/25/2015] [Accepted: 05/26/2015] [Indexed: 12/17/2022]
Abstract
Quorum sensing (QS) plays critical roles in virulence gene expression and the pathogenesis of Pseudomonas aeruginosa, an important human pathogen. However, the regulatory effects, especially that occur directly upstream of the QS system, remain largely unknown. Here, we review recent advances in the understanding of the key component of carbon catabolite repression (CCR) system and protein quality control (PQC) system in regulating the QS system in P. aeruginosa. We propose that PQC proteases Lon and ClpXP may have an important role in linking CCR with QS, and thus contribute to the integration of nutritional cues into the regulatory network governing the virulence factors expression in P. aeruginosa.
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Cloning, expression and characterization of UDP-N-acetylglucosamine enolpyruvyl transferase (MurA) from Wolbachia endosymbiont of human lymphatic filarial parasite Brugia malayi. PLoS One 2014; 9:e99884. [PMID: 24941309 PMCID: PMC4062475 DOI: 10.1371/journal.pone.0099884] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Accepted: 05/19/2014] [Indexed: 12/21/2022] Open
Abstract
Wolbachia, an endosymbiont of filarial nematode, is considered a promising target for treatment of lymphatic filariasis. Although functional characterization of the Wolbachia peptidoglycan assembly has not been fully explored, the Wolbachia genome provides evidence for coding all of the genes involved in lipid II biosynthesis, a part of peptidoglycan biosynthesis pathway. UDP-N-acetylglucosamine enolpyruvyl transferase (MurA) is one of the lipid II biosynthesis pathway enzymes and it has inevitably been recognized as an antibiotic target. In view of the vital role of MurA in bacterial viability and survival, MurA ortholog from Wolbachia endosymbiont of Brugia malayi (wBm-MurA) was cloned, expressed and purified for further molecular characterization. The enzyme kinetics and inhibition studies were undertaken using fosfomycin. wBm-MurA was found to be expressed in all the major life stages of B. malayi and was immunolocalized in Wolbachia within the microfilariae and female adults by the confocal microscopy. Sequence analysis suggests that the amino acids crucial for enzymatic activity are conserved. The purified wBm-MurA was shown to possess the EPSP synthase (3-phosphoshikimate 1-carboxyvinyltransferase) like activity at a broad pH range with optimal activity at pH 7.5 and 37°C temperature. The apparent affinity constant (Km) for the substrate UDP-N-acetylglucosamine was found to be 0.03149 mM and for phosphoenolpyruvate 0.009198 mM. The relative enzymatic activity was inhibited ∼2 fold in presence of fosfomycin. Superimposition of the wBm-MurA homology model with the structural model of Haemophilus influenzae (Hi-MurA) suggests binding of fosfomycin at the same active site. The findings suggest wBm-MurA to be a putative antifilarial drug target for screening of novel compounds.
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Nag JK, Shrivastava N, Chahar D, Gupta CL, Bajpai P, Misra-Bhattacharya S. Wolbachia transcription elongation factor "Wol GreA" interacts with α2ββ'σ subunits of RNA polymerase through its dimeric C-terminal domain. PLoS Negl Trop Dis 2014; 8:e2930. [PMID: 24945631 PMCID: PMC4063747 DOI: 10.1371/journal.pntd.0002930] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Accepted: 04/25/2014] [Indexed: 01/16/2023] Open
Abstract
OBJECTIVES Wolbachia, an endosymbiont of filarial nematode, is considered a promising target for therapy against lymphatic filariasis. Transcription elongation factor GreA is an essential factor that mediates transcriptional transition from abortive initiation to productive elongation by stimulating the escape of RNA polymerase (RNAP) from native prokaryotic promoters. Upon screening of 6257 essential bacterial genes, 57 were suggested as potential future drug targets, and GreA is among these. The current study emphasized the characterization of Wol GreA with its domains. METHODOLOGY/PRINCIPAL FINDINGS Biophysical characterization of Wol GreA with its N-terminal domain (NTD) and C-terminal domain (CTD) was performed with fluorimetry, size exclusion chromatography, and chemical cross-linking. Filter trap and far western blotting were used to determine the domain responsible for the interaction with α2ββ'σ subunits of RNAP. Protein-protein docking studies were done to explore residual interaction of RNAP with Wol GreA. The factor and its domains were found to be biochemically active. Size exclusion and chemical cross-linking studies revealed that Wol GreA and CTD exist in a dimeric conformation while NTD subsists in monomeric conformation. Asp120, Val121, Ser122, Lys123, and Ser134 are the residues of CTD through which monomers of Wol GreA interact and shape into a dimeric conformation. Filter trap, far western blotting, and protein-protein docking studies revealed that dimeric CTD of Wol GreA through Lys82, Ser98, Asp104, Ser105, Glu106, Tyr109, Glu116, Asp120, Val121, Ser122, Ser127, Ser129, Lys140, Glu143, Val147, Ser151, Glu153, and Phe163 residues exclusively participates in binding with α2ββ'σ subunits of polymerase. CONCLUSIONS/SIGNIFICANCE To the best of our knowledge, this research is the first documentation of the residual mode of action in wolbachial mutualist. Therefore, findings may be crucial to understanding the transcription mechanism of this α-proteobacteria and in deciphering the role of Wol GreA in filarial development.
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Affiliation(s)
- Jeetendra Kumar Nag
- Division of Parasitology, CSIR-Central Drug Research Institute, Lucknow, India
| | - Nidhi Shrivastava
- Division of Parasitology, CSIR-Central Drug Research Institute, Lucknow, India
| | - Dhanvantri Chahar
- Division of Parasitology, CSIR-Central Drug Research Institute, Lucknow, India
- Academy of Scientific and Innovative Research, New Delhi, India
| | | | - Preeti Bajpai
- Department of Biosciences, Integral University, Lucknow, India
| | - Shailja Misra-Bhattacharya
- Division of Parasitology, CSIR-Central Drug Research Institute, Lucknow, India
- Academy of Scientific and Innovative Research, New Delhi, India
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Integrated transcriptomic and proteomic analysis of the global response of Wolbachia to doxycycline-induced stress. ISME JOURNAL 2013; 8:925-37. [PMID: 24152719 PMCID: PMC3960535 DOI: 10.1038/ismej.2013.192] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Revised: 09/12/2013] [Accepted: 09/20/2013] [Indexed: 01/05/2023]
Abstract
The bacterium Wolbachia (order Rickettsiales), representing perhaps the most abundant vertically transmitted microbe worldwide, infects arthropods and filarial nematodes. In arthropods, Wolbachia can induce reproductive alterations and interfere with the transmission of several arthropod-borne pathogens. In addition, Wolbachia is an obligate mutualist of the filarial parasites that cause lymphatic filariasis and onchocerciasis in the tropics. Targeting Wolbachia with tetracycline antibiotics leads to sterilisation and ultimately death of adult filariae. However, several weeks of treatment are required, restricting the implementation of this control strategy. To date, the response of Wolbachia to stress has not been investigated, and almost nothing is known about global regulation of gene expression in this organism. We exposed an arthropod Wolbachia strain to doxycycline in vitro, and analysed differential expression by directional RNA-seq and label-free, quantitative proteomics. We found that Wolbachia responded not only by modulating expression of the translation machinery, but also by upregulating nucleotide synthesis and energy metabolism, while downregulating outer membrane proteins. Moreover, Wolbachia increased the expression of a key component of the twin-arginine translocase (tatA) and a phosphate ABC transporter ATPase (PstB); the latter is associated with decreased susceptibility to antimicrobials in free-living bacteria. Finally, the downregulation of 6S RNA during translational inhibition suggests that this small RNA is involved in growth rate control. Despite its highly reduced genome, Wolbachia shows a surprising ability to regulate gene expression during exposure to a potent stressor. Our findings have general relevance for the chemotherapy of obligate intracellular bacteria and the mechanistic basis of persistence in the Rickettsiales.
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Sass P, Brötz-Oesterhelt H. Bacterial cell division as a target for new antibiotics. Curr Opin Microbiol 2013; 16:522-30. [DOI: 10.1016/j.mib.2013.07.006] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Revised: 07/04/2013] [Accepted: 07/04/2013] [Indexed: 01/22/2023]
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Sowole MA, Alexopoulos JA, Cheng YQ, Ortega J, Konermann L. Activation of ClpP protease by ADEP antibiotics: insights from hydrogen exchange mass spectrometry. J Mol Biol 2013; 425:4508-19. [PMID: 23948506 DOI: 10.1016/j.jmb.2013.08.005] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Revised: 07/27/2013] [Accepted: 08/06/2013] [Indexed: 10/26/2022]
Abstract
The bacterial protease ClpP consists of 14 subunits that assemble into two stacked heptameric rings. The central degradation chamber can be accessed via axial pores. In free ClpP, these pores are obstructed by the N-terminal regions of the seven subunits at either end of the barrel. Acyldepsipeptides (ADEPs) are antibacterial compounds that bind in hydrophobic clefts surrounding the pore region, causing the pores to open up. The ensuing uncontrolled degradation of intracellular proteins is responsible for the antibiotic activity of ADEPs. Recently published X-ray structures yielded conflicting models regarding the conformation adopted by the N-terminal regions in the open state. Here, we use hydrogen/deuterium exchange (HDX) mass spectrometry to obtain complementary insights into the ClpP behavior with and without ADEP1. Ligand binding causes rigidification of the equatorial belt, accompanied by destabilization in the vicinity of the binding clefts. The N-terminal regions undergo rapid deuteration with only minor changes after ADEP1 binding, revealing a lack of stable H-bonding. Our data point to a mechanism where the pore opening mechanism is mediated primarily by changes in the packing of N-terminal nonpolar side chains. We propose that a "hydrophobic plug" causes pore blockage in ligand-free ClpP. ADEP1 binding provides new hydrophobic anchor points that nonpolar N-terminal residues can interact with. In this way, ADEP1 triggers the transition to an open conformation, where nonpolar moieties are clustered around the rim of the pore. This proposed mechanism helps reconcile the conflicting models that had been put forward earlier.
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Affiliation(s)
- Modupeola A Sowole
- Department of Chemistry, The University of Western Ontario, London, Ontario, N6A 5B7, Canada
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Wolbachia: Can we save lives with a great pandemic? Trends Parasitol 2013; 29:385-93. [PMID: 23845310 DOI: 10.1016/j.pt.2013.06.003] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Revised: 06/07/2013] [Accepted: 06/10/2013] [Indexed: 11/21/2022]
Abstract
Wolbachia pipientis is the most common bacterial infection in the animal world and wields a vast influence on invertebrate reproduction, sex determination, speciation, and behavior worldwide. These avenues of research have made seminal gains, including the latest use of Wolbachia to alter mosquito populations and a strengthened focus on using anti-Wolbachia therapies against filarial nematode infections. This work is further bolstered by a more refined knowledge of Wolbachia biology spanning mechanisms to relevance. Here we tally the most up-to-date knowledge in the field and review the immense implications that this global infection has for the basic and applied life sciences.
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