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Sarangi A, Singh SP, Das BS, Rajput S, Fatima S, Bhattacharya D. Mycobacterial biofilms: A therapeutic target against bacterial persistence and generation of antibiotic resistance. Heliyon 2024; 10:e32003. [PMID: 38882302 PMCID: PMC11176842 DOI: 10.1016/j.heliyon.2024.e32003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Revised: 05/24/2024] [Accepted: 05/27/2024] [Indexed: 06/18/2024] Open
Abstract
Mycobacterium tuberculosis (M. tb) is the causative agent of Tuberculosis, one of the deadliest infectious diseases. According to the WHO Report 2023, in 2022, approximately 10.6 million people got infected with TB, and 1.6 million died. It has multiple antibiotics for treatment, but the major drawback of anti-tuberculosis therapy (ATT) is, its prolonged treatment duration. The major contributors to the lengthy treatment period are mycobacterial persistence and drug tolerance. Persistent M. tb is phenotypically drug tolerant and metabolically slow down which makes it difficult to be eliminated during ATT. These persisting bacteria are a huge reservoir of impending disease, waiting to get reactivated upon the onset of an immune compromising state. Directly Observed Treatment Short-course, although effective against replicating bacteria; fails to eliminate the drug-tolerant persisters making TB still the second-highest killer globally. There are different mechanisms for the development of drug-tolerant mycobacterial populations being investigated. Recently, the role of biofilms in the survival and host-evasion mechanism of persisters has come to light. Therefore, it is crucial to understand the mechanism of adaptation, survival and attainment of drug tolerance by persisting M. tb-populations, in order to design better immune responses and therapeutics for the effective elimination of these bacteria by reducing the duration of treatment and also circumvent the generation of drug-resistance to achieve the goal of global eradication of TB. This review summarizes the drug-tolerance mechanism and biofilms' role in providing a niche to dormant-M.tb. We also discuss methods of targeting biofilms to achieve sterile eradication of the mycobacteria and prevent its reactivation by achieving adequate immune responses.
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Affiliation(s)
- Ashirbad Sarangi
- Centre for Biotechnology, School of Pharmaceutical Sciences, Siksha 'O' Anusandhan (Deemed to be University), Bhubaneswar, Odisha, India
| | - Shashi Prakash Singh
- Vaccine and Gene Therapy Institute (VGTI) Oregon National Primate Research Centre (ONPRC) Oregon Health and Science University (OHSU) Beaverton, Oregon, USA
| | - Bhabani Shankar Das
- Centre for Biotechnology, School of Pharmaceutical Sciences, Siksha 'O' Anusandhan (Deemed to be University), Bhubaneswar, Odisha, India
| | - Sristi Rajput
- Departmental of Biological Sciences, Indian Institute of Science Education and Research (IISER), Bhopal, Madhya Pradesh, India
| | - Samreen Fatima
- UMass Chan Medical School, University of Massachusetts, Worcester, MA, USA
| | - Debapriya Bhattacharya
- Centre for Biotechnology, School of Pharmaceutical Sciences, Siksha 'O' Anusandhan (Deemed to be University), Bhubaneswar, Odisha, India
- Departmental of Biological Sciences, Indian Institute of Science Education and Research (IISER), Bhopal, Madhya Pradesh, India
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2
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Toward understanding the emergence of life: A dual function of the system of nucleotides in the metabolically closed autopoietic organization. Biosystems 2023; 224:104837. [PMID: 36649884 DOI: 10.1016/j.biosystems.2023.104837] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 01/05/2023] [Accepted: 01/10/2023] [Indexed: 01/15/2023]
Abstract
General structure of metabolism includes the reproduction of catalysts that govern metabolism. In this structure, the system becomes autopoietic in the sense of Maturana and Varela, and it is closed to efficient causation as defined by Robert Rosen. The autopoietic maintenance and operation of the catalysts takes place via the set of free nucleotides while the synthesis of catalysts occurs via the information encoded by the set of nucleotides arranged in polymers of RNA and DNA. Both energy charge and genetic information use the components of the same pool of nucleoside triphosphates, which is equilibrated by thermodynamic buffering enzymes such as nucleoside diphosphate kinase and adenylate kinase. This occurs in a way that the system becomes internally stable and metabolically closed, which initially could be realized at the level of ribozymes catalyzing basic metabolic reactions as well as own reproduction. The function of ATP, GTP, UTP, and CTP is dual, as these species participate both in the general metabolism as free nucleotides and in the transfer of genetic information via covalent polymerization to nucleic acids. The changes in their pools directly impact both bioenergetic pathways and nucleic acid turnover. Here we outline the concept of metabolic closure of biosystems grounded in the dual function of nucleotide coenzymes that serve both as energetic and informational molecules and through this duality generate the autopoietic performance and the ability for codepoietic evolutionary transformations of living systems starting from the emergence of prebiotic systems.
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3
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Ongwae GM, Lepori I, Chordia MD, Dalesandro BE, Apostolos AJ, Siegrist MS, Pires MM. Measurement of Small Molecule Accumulation into Diderm Bacteria. ACS Infect Dis 2023; 9:97-110. [PMID: 36530146 DOI: 10.1021/acsinfecdis.2c00435] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Some of the most dangerous bacterial pathogens (Gram-negative and mycobacterial) deploy a formidable secondary membrane barrier to reduce the influx of exogenous molecules. For Gram-negative bacteria, this second exterior membrane is known as the outer membrane (OM), while for the Gram-indeterminate Mycobacteria, it is known as the "myco" membrane. Although different in composition, both the OM and mycomembrane are key structures that restrict the passive permeation of small molecules into bacterial cells. Although it is well-appreciated that such structures are principal determinants of small molecule permeation, it has proven to be challenging to assess this feature in a robust and quantitative way or in complex, infection-relevant settings. Herein, we describe the development of the bacterial chloro-alkane penetration assay (BaCAPA), which employs the use of a genetically encoded protein called HaloTag, to measure the uptake and accumulation of molecules into model Gram-negative and mycobacterial species, Escherichia coli and Mycobacterium smegmatis, respectively, and into the human pathogen Mycobacterium tuberculosis. The HaloTag protein can be directed to either the cytoplasm or the periplasm of bacteria. This offers the possibility of compartmental analysis of permeation across individual cell membranes. Significantly, we also showed that BaCAPA can be used to analyze the permeation of molecules into host cell-internalized E. coli and M. tuberculosis, a critical capability for analyzing intracellular pathogens. Together, our results show that BaCAPA affords facile measurement of permeability across four barriers: the host plasma and phagosomal membranes and the diderm bacterial cell envelope.
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Affiliation(s)
- George M Ongwae
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904, United States
| | - Irene Lepori
- Department of Microbiology, University of Massachusetts, Amherst, Massachusetts 01003, United States
| | - Mahendra D Chordia
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904, United States
| | - Brianna E Dalesandro
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904, United States
| | - Alexis J Apostolos
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904, United States
| | - M Sloan Siegrist
- Department of Microbiology, University of Massachusetts, Amherst, Massachusetts 01003, United States.,Molecular and Cellular Biology Graduate Program, University of Massachusetts, Amherst, Massachusetts 01003, United States
| | - Marcos M Pires
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904, United States
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4
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Trejo A, Masdeu C, Serrano-Pérez I, Pedrola M, Juanola N, Ghashghaei O, Jiménez-Galisteo G, Lavilla R, Palacios F, Alonso C, Viñas M. Efficient AntiMycolata Agents by Increasing the Lipophilicity of Known Antibiotics through Multicomponent Reactions. Antibiotics (Basel) 2023; 12:83. [PMID: 36671284 PMCID: PMC9854905 DOI: 10.3390/antibiotics12010083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 12/28/2022] [Accepted: 12/29/2022] [Indexed: 01/06/2023] Open
Abstract
New antibiotic agents were prepared using Povarov and Ugi multicomponent reactions upon the known drugs sulfadoxine and dapsone. The prepared derivatives, with increased lipophilicity, showed improved efficiency against Mycolata bacteria. Microbiological guidance for medicinal chemistry is a powerful tool to design new and effective antimicrobials. In this case, the readily synthesized compounds open new possibilities in the search for antimicrobials active on mycolic acid-containing bacteria.
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Affiliation(s)
- Angela Trejo
- Departamento de Química Orgánica I, Facultad de Farmacia, Universidad del País Vasco/Euskal Herriko, Unibertsitatea (UPV/EHU), Paseo de la Universidad 7, 01006 Vitoria-Gasteiz, Spain
| | - Carme Masdeu
- Departamento de Química Orgánica I, Facultad de Farmacia, Universidad del País Vasco/Euskal Herriko, Unibertsitatea (UPV/EHU), Paseo de la Universidad 7, 01006 Vitoria-Gasteiz, Spain
| | - Irene Serrano-Pérez
- Laboratory of Molecular Microbiology & Antimicrobials, Department of Pathology & Experimental Therapeutics, Medical School, University of Barcelona and IDIBELL, Feixa Llarga, s/n, 08907 Hospitalet de Llobregat, Spain
| | - Marina Pedrola
- Laboratory of Medicinal Chemistry, Faculty of Pharmacy and Food Sciences and Institute of Biomedicine (IBUB), University of Barcelona, Av. de Joan XXIII, 27-31, 08028 Barcelona, Spain
| | - Narcís Juanola
- Laboratory of Medicinal Chemistry, Faculty of Pharmacy and Food Sciences and Institute of Biomedicine (IBUB), University of Barcelona, Av. de Joan XXIII, 27-31, 08028 Barcelona, Spain
| | - Ouldouz Ghashghaei
- Laboratory of Medicinal Chemistry, Faculty of Pharmacy and Food Sciences and Institute of Biomedicine (IBUB), University of Barcelona, Av. de Joan XXIII, 27-31, 08028 Barcelona, Spain
| | - Guadalupe Jiménez-Galisteo
- Laboratory of Molecular Microbiology & Antimicrobials, Department of Pathology & Experimental Therapeutics, Medical School, University of Barcelona and IDIBELL, Feixa Llarga, s/n, 08907 Hospitalet de Llobregat, Spain
| | - Rodolfo Lavilla
- Laboratory of Medicinal Chemistry, Faculty of Pharmacy and Food Sciences and Institute of Biomedicine (IBUB), University of Barcelona, Av. de Joan XXIII, 27-31, 08028 Barcelona, Spain
| | - Francisco Palacios
- Departamento de Química Orgánica I, Facultad de Farmacia, Universidad del País Vasco/Euskal Herriko, Unibertsitatea (UPV/EHU), Paseo de la Universidad 7, 01006 Vitoria-Gasteiz, Spain
| | - Concepción Alonso
- Departamento de Química Orgánica I, Facultad de Farmacia, Universidad del País Vasco/Euskal Herriko, Unibertsitatea (UPV/EHU), Paseo de la Universidad 7, 01006 Vitoria-Gasteiz, Spain
| | - Miguel Viñas
- Laboratory of Molecular Microbiology & Antimicrobials, Department of Pathology & Experimental Therapeutics, Medical School, University of Barcelona and IDIBELL, Feixa Llarga, s/n, 08907 Hospitalet de Llobregat, Spain
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5
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Tan YZ, Mancia F. Structure and Function of Mycobacterial Arabinofuranosyltransferases. Subcell Biochem 2022; 99:379-391. [PMID: 36151383 DOI: 10.1007/978-3-031-00793-4_12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The mycobacteria genus is responsible for numerous infectious diseases that have afflicted the human race since antiquity-tuberculosis and leprosy in particular. An important contributor to their evolutionary success is their unique cell envelope, which constitutes a quasi-impermeable barrier, protecting the microorganism from external threats, antibiotics included. The arabinofuranosyltransferases are a family of enzymes, unique to the Actinobacteria family that mycobacteria genus belongs to, that are critical to building of this cell envelope. In this chapter, we will analyze available structures of members of the mycobacterial arabinofuranosyltransferase, clarify their function, as well as explore the common themes present amongst this family of enzymes, as revealed by recent research.
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Affiliation(s)
- Yong Zi Tan
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore.
- Disease Intervention Technology Laboratory (DITL), Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore.
| | - Filippo Mancia
- Department of Physiology and Cellular Biophysics, Columbia University, NY, USA
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6
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Hosfelt J, Richards A, Zheng M, Adura C, Nelson B, Yang A, Fay A, Resager W, Ueberheide B, Glickman JF, Lupoli TJ. An allosteric inhibitor of bacterial Hsp70 chaperone potentiates antibiotics and mitigates resistance. Cell Chem Biol 2021; 29:854-869.e9. [PMID: 34818532 DOI: 10.1016/j.chembiol.2021.11.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Revised: 09/20/2021] [Accepted: 11/02/2021] [Indexed: 12/23/2022]
Abstract
DnaK is the bacterial homolog of Hsp70, an ATP-dependent chaperone that helps cofactor proteins to catalyze nascent protein folding and salvage misfolded proteins. In the pathogen Mycobacterium tuberculosis, the causative agent of tuberculosis (TB), DnaK and its cofactors are proposed antimycobacterial targets, yet few small-molecule inhibitors or probes exist for these families of proteins. Here, we describe the repurposing of a drug called telaprevir that is able to allosterically inhibit the ATPase activity of DnaK and to prevent chaperone function by mimicking peptide substrates. In mycobacterial cells, telaprevir disrupts DnaK- and cofactor-mediated cellular proteostasis, resulting in enhanced efficacy of aminoglycoside antibiotics and reduced resistance to the frontline TB drug rifampin. Hence, this work contributes to a small but growing collection of protein chaperone inhibitors, and it demonstrates that these molecules disrupt bacterial mechanisms of survival in the presence of different antibiotic classes.
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Affiliation(s)
- Jordan Hosfelt
- Department of Chemistry, New York University, New York, NY 10003, USA
| | - Aweon Richards
- Department of Chemistry, New York University, New York, NY 10003, USA
| | - Meng Zheng
- Department of Chemistry, New York University, New York, NY 10003, USA
| | - Carolina Adura
- High-Throughput and Spectroscopy Resource Center, The Rockefeller University, New York, NY 10065, USA
| | - Brock Nelson
- Department of Chemistry, New York University, New York, NY 10003, USA
| | - Amy Yang
- Department of Chemistry, New York University, New York, NY 10003, USA
| | - Allison Fay
- Immunology Program, Sloan Kettering Insitute, New York, NY 10065, USA
| | - William Resager
- Departments of Biochemistry and Molecular Pharmacology, Neurology and Director Proteomics Lab, Division of Advanced Research Technologies, NYU Grossman School of Medicine, New York, NY 10016, USA
| | - Beatrix Ueberheide
- Departments of Biochemistry and Molecular Pharmacology, Neurology and Director Proteomics Lab, Division of Advanced Research Technologies, NYU Grossman School of Medicine, New York, NY 10016, USA
| | - J Fraser Glickman
- High-Throughput and Spectroscopy Resource Center, The Rockefeller University, New York, NY 10065, USA
| | - Tania J Lupoli
- Department of Chemistry, New York University, New York, NY 10003, USA.
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7
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Tandi M, Sundriyal S. Recent trends in the design of antimicrobial agents using Ugi-multicomponent reaction. J INDIAN CHEM SOC 2021. [DOI: 10.1016/j.jics.2021.100106] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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8
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First Penicillin-Binding Protein Occupancy Patterns for 15 β-Lactams and β-Lactamase Inhibitors in Mycobacterium abscessus. Antimicrob Agents Chemother 2020; 65:AAC.01956-20. [PMID: 33106266 DOI: 10.1128/aac.01956-20] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 10/21/2020] [Indexed: 02/06/2023] Open
Abstract
Mycobacterium abscessus causes serious infections that often require over 18 months of antibiotic combination therapy. There is no standard regimen for the treatment of M. abscessus infections, and the multitude of combinations that have been used clinically have had low success rates and high rates of toxicities. With β-lactam antibiotics being safe, double β-lactam and β-lactam/β-lactamase inhibitor combinations are of interest for improving the treatment of M. abscessus infections and minimizing toxicity. However, a mechanistic approach for building these combinations is lacking since little is known about which penicillin-binding protein (PBP) target receptors are inactivated by different β-lactams in M. abscessus We determined the preferred PBP targets of 13 β-lactams and 2 β-lactamase inhibitors in two M. abscessus strains and identified PBP sequences by proteomics. The Bocillin FL binding assay was used to determine the β-lactam concentrations that half-maximally inhibited Bocillin binding (50% inhibitory concentrations [IC50s]). Principal component analysis identified four clusters of PBP occupancy patterns. Carbapenems inactivated all PBPs at low concentrations (0.016 to 0.5 mg/liter) (cluster 1). Cephalosporins (cluster 2) inactivated PonA2, PonA1, and PbpA at low (0.031 to 1 mg/liter) (ceftriaxone and cefotaxime) or intermediate (0.35 to 16 mg/liter) (ceftazidime and cefoxitin) concentrations. Sulbactam, aztreonam, carumonam, mecillinam, and avibactam (cluster 3) inactivated the same PBPs as cephalosporins but required higher concentrations. Other penicillins (cluster 4) specifically targeted PbpA at 2 to 16 mg/liter. Carbapenems, ceftriaxone, and cefotaxime were the most promising β-lactams since they inactivated most or all PBPs at clinically relevant concentrations. These first PBP occupancy patterns in M. abscessus provide a mechanistic foundation for selecting and optimizing safe and effective combination therapies with β-lactams.
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9
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Dai T, Xie J, Zhu Q, Kamariza M, Jiang K, Bertozzi CR, Rao J. A Fluorogenic Trehalose Probe for Tracking Phagocytosed Mycobacterium tuberculosis. J Am Chem Soc 2020; 142:15259-15264. [DOI: 10.1021/jacs.0c07700] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Tingting Dai
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Jinghang Xie
- Department of Radiology, Molecular Imaging Program at Stanford, Stanford University School of Medicine, Stanford, California 94305, United States
| | - Qihua Zhu
- Department of Radiology, Molecular Imaging Program at Stanford, Stanford University School of Medicine, Stanford, California 94305, United States
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, 211198, China
- Jiangsu Key Laboratory of Drug Design and Optimization, Department of Medicinal Chemistry, China Pharmaceutical University, Nanjing 211198, China
| | - Mireille Kamariza
- Department of Biology, Stanford University, Stanford, California 94305, United States
| | - Ke Jiang
- Department of Radiology, Molecular Imaging Program at Stanford, Stanford University School of Medicine, Stanford, California 94305, United States
| | - Carolyn R. Bertozzi
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
- Howard Hughes Medical Institute, Stanford University, Stanford, California 94305, United States
| | - Jianghong Rao
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
- Department of Radiology, Molecular Imaging Program at Stanford, Stanford University School of Medicine, Stanford, California 94305, United States
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10
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Tan YZ, Zhang L, Rodrigues J, Zheng RB, Giacometti SI, Rosário AL, Kloss B, Dandey VP, Wei H, Brunton R, Raczkowski AM, Athayde D, Catalão MJ, Pimentel M, Clarke OB, Lowary TL, Archer M, Niederweis M, Potter CS, Carragher B, Mancia F. Cryo-EM Structures and Regulation of Arabinofuranosyltransferase AftD from Mycobacteria. Mol Cell 2020; 78:683-699.e11. [PMID: 32386575 PMCID: PMC7263364 DOI: 10.1016/j.molcel.2020.04.014] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 02/21/2020] [Accepted: 04/13/2020] [Indexed: 01/21/2023]
Abstract
Mycobacterium tuberculosis causes tuberculosis, a disease that kills over 1 million people each year. Its cell envelope is a common antibiotic target and has a unique structure due, in part, to two lipidated polysaccharides-arabinogalactan and lipoarabinomannan. Arabinofuranosyltransferase D (AftD) is an essential enzyme involved in assembling these glycolipids. We present the 2.9-Å resolution structure of M. abscessus AftD, determined by single-particle cryo-electron microscopy. AftD has a conserved GT-C glycosyltransferase fold and three carbohydrate-binding modules. Glycan array analysis shows that AftD binds complex arabinose glycans. Additionally, AftD is non-covalently complexed with an acyl carrier protein (ACP). 3.4- and 3.5-Å structures of a mutant with impaired ACP binding reveal a conformational change, suggesting that ACP may regulate AftD function. Mutagenesis experiments using a conditional knockout constructed in M. smegmatis confirm the essentiality of the putative active site and the ACP binding for AftD function.
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Affiliation(s)
- Yong Zi Tan
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY 10032, USA; National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY 10027, USA
| | - Lei Zhang
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - José Rodrigues
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa (ITQB NOVA), 2780-157 Oeiras, Portugal
| | | | - Sabrina I Giacometti
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY 10032, USA
| | - Ana L Rosário
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa (ITQB NOVA), 2780-157 Oeiras, Portugal
| | - Brian Kloss
- Center on Membrane Protein Production and Analysis, New York Structural Biology Center, New York, NY 10027, USA
| | - Venkata P Dandey
- National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY 10027, USA
| | - Hui Wei
- National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY 10027, USA
| | - Richard Brunton
- Department of Chemistry, University of Alberta, Edmonton, AB T6G 2G2, Canada
| | - Ashleigh M Raczkowski
- Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY 10027, USA
| | - Diogo Athayde
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa (ITQB NOVA), 2780-157 Oeiras, Portugal
| | - Maria João Catalão
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, 1649-003 Lisboa, Portugal
| | - Madalena Pimentel
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, 1649-003 Lisboa, Portugal
| | - Oliver B Clarke
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY 10032, USA; Department of Anesthesiology, Columbia University, New York, NY 10032, USA
| | - Todd L Lowary
- Department of Chemistry, University of Alberta, Edmonton, AB T6G 2G2, Canada; Institute of Biological Chemistry, Academia Sinica, Academia Road, Section 2, #128 Nangang, Taipei 11529, Taiwan
| | - Margarida Archer
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa (ITQB NOVA), 2780-157 Oeiras, Portugal
| | - Michael Niederweis
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Clinton S Potter
- National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY 10027, USA; Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY 10027, USA; Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Bridget Carragher
- National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY 10027, USA; Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY 10027, USA; Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA.
| | - Filippo Mancia
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY 10032, USA.
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11
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WQ-3810: A new fluoroquinolone with a high potential against fluoroquinolone-resistant Mycobacterium tuberculosis. Tuberculosis (Edinb) 2019; 120:101891. [PMID: 31778929 DOI: 10.1016/j.tube.2019.101891] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 11/06/2019] [Accepted: 11/17/2019] [Indexed: 11/23/2022]
Abstract
Fluoroquinolone (FQ) resistance in Mycobacterium tuberculosis (Mtb), caused by amino acid substitutions in DNA gyrase, has been increasingly reported worldwide. WQ-3810 is a newly developed FQ that is highly active against FQ-resistant pathogens; however, its activity against Mtb has not been evaluated. Herein we examined the efficacy of WQ-3810 against Mtb through the use of recombinant Mtb DNA gyrases. In addition, in vitro antimycobacterial activity of WQ-3810 was evaluated against recombinant Mtb var. bovis Bacille Calmette-Guérin strains in which gyrase-coding genes were replaced with Mtb variants containing resistance-conferring mutations. WQ-3810 showed a higher inhibitory activity than levofloxacin against most recombinant DNA gyrases with FQ-resistance mutations. Furthermore, WQ-3810 showed inhibition even against a DNA gyrase variant harboring a G88C mutation which is thought to confer the highest resistance against FQs in clinical Mtb isolates. In contrast, the FQ susceptibility test showed that WQ-3810 had relatively weak mycobactericidal activity compared with moxifloxacin. However, the combination of WQ-3810 and ethambutol showed the greatest degree of synergistic activity against recombinant strains. Since FQs and ethambutol have been used in multi-drug therapy for tuberculosis, WQ-3810 might represent a new, potent anti-tuberculosis drug that can be effective even against FQ-resistant Mtb strains.
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12
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El-Fakharany EM, Redwan EM. Protein-lipid complexes: molecular structure, current scenarios and mechanisms of cytotoxicity. RSC Adv 2019; 9:36890-36906. [PMID: 35539089 PMCID: PMC9075609 DOI: 10.1039/c9ra07127j] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 10/21/2019] [Indexed: 02/04/2023] Open
Abstract
Some natural proteins can be complexed with oleic acid (OA) to form an active protein-lipid formulation that can induce tumor-selective apoptosis. The first explored protein was human milk α-lactalbumin (α-LA), called HAMLET when composed with OA in antitumor form. Several groups have prepared active protein-lipid complexes using a variety of approaches, all of which depend on target protein destabilization or direct OA-protein incubation to alter pH to acid or alkaline condition. In addition to performing vital roles in inflammatory processes and immune responses, fatty acids can disturb different metabolic pathways and cellular signals. Therefore, the tumoricidal action of these complexes is related to OA rather than the protein that keeps OA in solution and acts as a vehicle for transferring OA molecules to tumor cells. However, other studies have suggested that the antitumor efficacy of these complexes was exerted by both protein and OA together. The potential is not limited to the anti-tumor activity of protein-lipid complexes but extends to other functions such as bactericidal activity. The protein shell enhances the solubility and stability of the bound fatty acid. These protein-lipid complexes are promising candidates for fighting various cancer types and managing bacterial and viral infections.
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Affiliation(s)
- Esmail M El-Fakharany
- Protein Research Department, Genetic Engineering and Biotechnology Research Institute, City for Scientific Research and Technology Applications (SRTA-City) New Borg EL-Arab 21934 Alexandria Egypt
| | - Elrashdy M Redwan
- Protein Research Department, Genetic Engineering and Biotechnology Research Institute, City for Scientific Research and Technology Applications (SRTA-City) New Borg EL-Arab 21934 Alexandria Egypt
- Department of Biological Sciences, Faculty of Sciences, King Abdulaziz University P. O. Box 80203 Jeddah Saudi Arabia
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13
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Cheng Y, Xie J, Lee KH, Gaur RL, Song A, Dai T, Ren H, Wu J, Sun Z, Banaei N, Akin D, Rao J. Rapid and specific labeling of single live Mycobacterium tuberculosis with a dual-targeting fluorogenic probe. Sci Transl Med 2019; 10:10/454/eaar4470. [PMID: 30111644 DOI: 10.1126/scitranslmed.aar4470] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Accepted: 06/26/2018] [Indexed: 01/07/2023]
Abstract
Tuberculosis (TB) remains a public health crisis and a leading cause of infection-related death globally. Although in high demand, imaging technologies that enable rapid, specific, and nongenetic labeling of live Mycobacterium tuberculosis (Mtb) remain underdeveloped. We report a dual-targeting strategy to develop a small molecular probe (CDG-DNB3) that can fluorescently label single bacilli within 1 hour. CDG-DNB3 fluoresces upon activation of the β-lactamase BlaC, a hydrolase naturally expressed in Mtb, and the fluorescent product is retained through covalent modification of the Mtb essential enzyme decaprenylphosphoryl-β-d-ribose 2'-epimerase (DprE1). This dual-targeting probe not only discriminates live from dead Bacillus Calmette-Guérin (BCG) but also shows specificity for Mtb over other bacterial species including 43 nontuberculosis mycobacteria (NTM). In addition, CDG-DNB3 can image BCG phagocytosis in real time, as well as Mtb in patients' sputum. Together with a low-cost, self-driven microfluidic chip, we have achieved rapid labeling and automated quantification of live BCG. This labeling approach should find many potential applications for research toward TB pathogenesis, treatment efficacy assessment, and diagnosis.
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Affiliation(s)
- Yunfeng Cheng
- Departments of Radiology and Chemistry, Molecular Imaging Program at Stanford, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Jinghang Xie
- Departments of Radiology and Chemistry, Molecular Imaging Program at Stanford, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Kyung-Hyun Lee
- Departments of Radiology and Chemistry, Molecular Imaging Program at Stanford, Stanford University School of Medicine, Stanford, CA 94305, USA.,Institute of Bioengineering and Nanotechnology, The Nanos, Singapore 138669, Singapore
| | - Rajiv L Gaur
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA.,Clinical Microbiology Laboratory, Stanford University Medical Center, Palo Alto, CA 94304, USA.,Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Aiguo Song
- Departments of Radiology and Chemistry, Molecular Imaging Program at Stanford, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Tingting Dai
- Departments of Radiology and Chemistry, Molecular Imaging Program at Stanford, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Hongjun Ren
- Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou 310018, P. R. China
| | - Jiannan Wu
- National Tuberculosis Clinical Laboratory, Beijing Chest Hospital, Capital Medical University, Beijing 101149, P. R. China.,Beijing Key Laboratory for Drug Resistance Tuberculosis Research, Beijing Tuberculosis and Thoracic Tumor Research Institute, Beijing 101149, P. R. China
| | - Zhaogang Sun
- National Tuberculosis Clinical Laboratory, Beijing Chest Hospital, Capital Medical University, Beijing 101149, P. R. China.,Beijing Key Laboratory for Drug Resistance Tuberculosis Research, Beijing Tuberculosis and Thoracic Tumor Research Institute, Beijing 101149, P. R. China
| | - Niaz Banaei
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA.,Clinical Microbiology Laboratory, Stanford University Medical Center, Palo Alto, CA 94304, USA.,Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Demir Akin
- Center for Cancer Nanotechnology Excellence, Department of Radiology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Jianghong Rao
- Departments of Radiology and Chemistry, Molecular Imaging Program at Stanford, Stanford University School of Medicine, Stanford, CA 94305, USA.
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14
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Ortega Ugalde S, Boot M, Commandeur JNM, Jennings P, Bitter W, Vos JC. Function, essentiality, and expression of cytochrome P450 enzymes and their cognate redox partners in Mycobacterium tuberculosis: are they drug targets? Appl Microbiol Biotechnol 2019; 103:3597-3614. [PMID: 30810776 PMCID: PMC6469627 DOI: 10.1007/s00253-019-09697-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 02/08/2019] [Accepted: 02/10/2019] [Indexed: 11/26/2022]
Abstract
This review covers the current knowledge of the cytochrome P450 enzymes (CYPs) of the human pathogen Mycobacterium tuberculosis (Mtb) and their endogenous redox partners, focusing on their biological function, expression, regulation, involvement in antibiotic resistance, and suitability for exploitation as antitubercular targets. The Mtb genome encodes twenty CYPs and nine associated redox partners required for CYP catalytic activity. Transposon insertion mutagenesis studies have established the (conditional) essentiality of several of these enzymes for in vitro growth and host infection. Biochemical characterization of a handful of Mtb CYPs has revealed that they have specific physiological functions in bacterial virulence and persistence in the host. Analysis of the transcriptional response of Mtb CYPs and redox partners to external insults and to first-line antibiotics used to treat tuberculosis showed a diverse expression landscape, suggesting for some enzymes a potential role in drug resistance. Combining the knowledge about the physiological roles and expression profiles indicates that, at least five Mtb CYPs, CYP121A1, CYP125A1, CYP139A1, CYP142A1, and CYP143A1, as well as two ferredoxins, FdxA and FdxC, can be considered promising novel therapeutic targets.
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Affiliation(s)
- Sandra Ortega Ugalde
- Division of Molecular Toxicology, Amsterdam Institute for Molecules Medicines and Systems (AIMMS), Faculty of Sciences, Vrije Universiteit, De Boelelaan 1108, 1081 HZ, Amsterdam, The Netherlands.
| | - Maikel Boot
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT, USA
| | - Jan N M Commandeur
- Division of Molecular Toxicology, Amsterdam Institute for Molecules Medicines and Systems (AIMMS), Faculty of Sciences, Vrije Universiteit, De Boelelaan 1108, 1081 HZ, Amsterdam, The Netherlands
| | - Paul Jennings
- Division of Molecular Toxicology, Amsterdam Institute for Molecules Medicines and Systems (AIMMS), Faculty of Sciences, Vrije Universiteit, De Boelelaan 1108, 1081 HZ, Amsterdam, The Netherlands
| | - Wilbert Bitter
- Section of Molecular Microbiology, AIMMS, Faculty of Sciences, Vrije Universiteit, Amsterdam, The Netherlands
| | - J Chris Vos
- Division of Molecular Toxicology, Amsterdam Institute for Molecules Medicines and Systems (AIMMS), Faculty of Sciences, Vrije Universiteit, De Boelelaan 1108, 1081 HZ, Amsterdam, The Netherlands
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15
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Jeon AB, Ackart DF, Li W, Jackson M, Melander RJ, Melander C, Abramovitch RB, Chicco AJ, Basaraba RJ, Obregón-Henao A. 2-aminoimidazoles collapse mycobacterial proton motive force and block the electron transport chain. Sci Rep 2019; 9:1513. [PMID: 30728417 PMCID: PMC6365497 DOI: 10.1038/s41598-018-38064-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 12/18/2018] [Indexed: 12/22/2022] Open
Abstract
There is an urgent need to develop new drugs against tuberculosis. In particular, it is critical to target drug tolerant Mycobacterium tuberculosis (M. tuberculosis), responsible, in part, for the lengthy antibiotic regimen required for treatment. We previously postulated that the presence of in vivo biofilm-like communities of M. tuberculosis could contribute to this drug tolerance. Consistent with this hypothesis, certain 2-aminoimidazole (2-AIs) molecules with anti-biofilm activity were shown to revert mycobacterial drug tolerance in an in vitro M. tuberculosis biofilm model. While exploring their mechanism of action, it was serendipitously observed that these 2-AI molecules also potentiated β-lactam antibiotics by affecting mycobacterial protein secretion and lipid export. As these two bacterial processes are energy-dependent, herein it was evaluated if 2-AI compounds affect mycobacterial bioenergetics. At low concentrations, 2B8, the lead 2-AI compound, collapsed both components of the proton motive force, similar to other cationic amphiphiles. Interestingly, however, the minimum inhibitory concentration of 2B8 against M. tuberculosis correlated with a higher drug concentration determined to interfere with the mycobacterial electron transport chain. Collectively, this study elucidates the mechanism of action of 2-AIs against M. tuberculosis, providing a tool to better understand mycobacterial bioenergetics and develop compounds with improved anti-mycobacterial activity.
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Affiliation(s)
- Albert Byungyun Jeon
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado, 80523, USA
- College of Veterinary Medicine, University of Florida, 2015 SW 16th Ave, Gainesville, Florida, 32608, USA
| | - David F Ackart
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado, 80523, USA
| | - Wei Li
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado, 80523, USA
| | - Mary Jackson
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado, 80523, USA
| | - Roberta J Melander
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina, 27695, USA
- Department of Chemistry & Biochemistry, University of Notre Dame, 251 Nieuwland Science Hall, Notre Dame, Indiana, 46556, USA
| | - Christian Melander
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina, 27695, USA
- Department of Chemistry & Biochemistry, University of Notre Dame, 251 Nieuwland Science Hall, Notre Dame, Indiana, 46556, USA
| | - Robert B Abramovitch
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, 48824, USA
| | - Adam J Chicco
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado, 80523, USA
| | - Randall J Basaraba
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado, 80523, USA.
| | - Andrés Obregón-Henao
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado, 80523, USA.
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16
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A Protein Complex from Human Milk Enhances the Activity of Antibiotics and Drugs against Mycobacterium tuberculosis. Antimicrob Agents Chemother 2019; 63:AAC.01846-18. [PMID: 30420480 DOI: 10.1128/aac.01846-18] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 10/31/2018] [Indexed: 01/06/2023] Open
Abstract
Mycobacterium tuberculosis, the causative agent of human tuberculosis (TB), has surpassed HIV/AIDS as the leading cause of death from a single infectious agent. The increasing occurrence of drug-resistant strains has become a major challenge for health care systems and, in some cases, has rendered TB untreatable. However, the development of new TB drugs has been plagued with high failure rates and costs. Alternative strategies to increase the efficacy of current TB treatment regimens include host-directed therapies or agents that make M. tuberculosis more susceptible to existing TB drugs. In this study, we show that HAMLET, an α-lactalbumin-oleic acid complex derived from human milk, has bactericidal activity against M. tuberculosis HAMLET consists of a micellar oleic acid core surrounded by a shell of partially denatured α-lactalbumin molecules and unloads oleic acid into cells upon contact with lipid membranes. At sublethal concentrations, HAMLET potentiated a remarkably broad array of TB drugs and antibiotics against M. tuberculosis For example, the minimal inhibitory concentrations of rifampin, bedaquiline, delamanid, and clarithromycin were decreased by 8- to 16-fold. HAMLET also killed M. tuberculosis and enhanced the efficacy of TB drugs inside macrophages, a natural habitat of M. tuberculosis Previous studies showed that HAMLET is stable after oral delivery in mice and nontoxic in humans and that it is possible to package hydrophobic compounds in the oleic acid core of HAMLET to increase their solubility and metabolic stability. The potential of HAMLET and other liprotides as drug delivery and sensitization agents in TB chemotherapy is discussed here.
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17
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Karade SS, Pandey S, Ansari A, Das S, Tripathi S, Arora A, Chopra S, Pratap JV, Dasgupta A. Rv3272 encodes a novel Family III CoA transferase that alters the cell wall lipid profile and protects mycobacteria from acidic and oxidative stress. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2018; 1867:317-330. [PMID: 30342240 DOI: 10.1016/j.bbapap.2018.10.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 10/01/2018] [Accepted: 10/16/2018] [Indexed: 11/26/2022]
Abstract
The availability of complete genome sequence of Mycobacterium tuberculosis has provided an important tool to understand the mycobacterial biology with respect to host-pathogen interaction, which is an unmet need of the hour owing to continuous increasing drug resistance. Hypothetical proteins are often an overlooked pool though half the genome encodes for such proteins of unknown function that could potentially play vital roles in mycobacterial biology. In this context, we report the structural and functional characterization of the hypothetical protein Rv3272. Sequence analysis classifies Rv3272 as a Family III CoA transferase with the classical two domain structure and conserved Aspartate residue (D175). The crystal structure of the wild type protein (2.2 Å) demonstrated the associated inter-locked dimer while that of the D175A mutant co-crystallized with octanoyl-CoA demonstrated relative movement between the two domains. Isothermal titration calorimetry studies indicate that Rv3272 binds to fatty acyl-CoAs of varying carbon chain lengths, with palmitoyl-CoA (C16:0) exhibiting maximum affinity. To determine the functional relevance of Rv3272 in mycobacterial biology, we ectopically expressed Rv3272 in M. smegmatis and assessed that its expression encodes significant alteration in cell surface with marked differences in triacylglycerol accumulation. Additionally, Rv3272 expression protects mycobacteria from acidic, oxidative and antibiotic stress under in vitro conditions. Taken together, these studies indicate a significant role for Rv3272 in host-pathogen interaction.
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Affiliation(s)
- Sharanbasappa Shrimant Karade
- Molecular and Structural Biology Division, CSIR-Central Drug Research Institute, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow 226031, Uttar Pradesh, India
| | - Shilpika Pandey
- Microbiology Division, CSIR-Central Drug Research Institute, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow 226031, Uttar Pradesh, India
| | - Ahmadullah Ansari
- Molecular and Structural Biology Division, CSIR-Central Drug Research Institute, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow 226031, Uttar Pradesh, India
| | - Swetarka Das
- Microbiology Division, CSIR-Central Drug Research Institute, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow 226031, Uttar Pradesh, India
| | - Sarita Tripathi
- Molecular and Structural Biology Division, CSIR-Central Drug Research Institute, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow 226031, Uttar Pradesh, India
| | - Ashish Arora
- Molecular and Structural Biology Division, CSIR-Central Drug Research Institute, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow 226031, Uttar Pradesh, India
| | - Sidharth Chopra
- Microbiology Division, CSIR-Central Drug Research Institute, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow 226031, Uttar Pradesh, India
| | - J Venkatesh Pratap
- Molecular and Structural Biology Division, CSIR-Central Drug Research Institute, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow 226031, Uttar Pradesh, India.
| | - Arunava Dasgupta
- Microbiology Division, CSIR-Central Drug Research Institute, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow 226031, Uttar Pradesh, India.
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18
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A Nonsense Mutation in Mycobacterium marinum That Is Suppressible by a Novel Mechanism. Infect Immun 2017; 85:IAI.00653-16. [PMID: 27789543 DOI: 10.1128/iai.00653-16] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 10/17/2016] [Indexed: 11/20/2022] Open
Abstract
Mycobacterial pathogens use the ESAT-6 system 1 (Esx-1) exporter to promote virulence. Previously, we used gene disruption and complementation to conclude that the MMAR_0039 gene in Mycobacterium marinum is required to promote Esx-1 export. Here we applied molecular genetics, proteomics, and whole-genome sequencing to demonstrate that the MMAR_0039 gene is not required for Esx-1 secretion or virulence. These findings suggest that we initially observed an indirect mechanism of genetic complementation. We identified a spontaneous nonsense mutation in a known Esx-1-associated gene which causes a loss of Esx-1 activity. We show that the Esx-1 function was restored by nonsense suppression. Moreover, we identified a polar mutation in the ppsC gene which reduced cellular impermeability but did not impact cytotoxicity in macrophages. Our studies reveal insight into Esx-1 export, nonsense suppression, and cell envelope lipid biogenesis.
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19
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Speer A, Sun J, Danilchanka O, Meikle V, Rowland JL, Walter K, Buck BR, Pavlenok M, Hölscher C, Ehrt S, Niederweis M. Surface hydrolysis of sphingomyelin by the outer membrane protein Rv0888 supports replication of Mycobacterium tuberculosis in macrophages. Mol Microbiol 2015; 97:881-97. [PMID: 26036301 DOI: 10.1111/mmi.13073] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/22/2015] [Indexed: 12/19/2022]
Abstract
Sphingomyelinases secreted by pathogenic bacteria play important roles in host-pathogen interactions ranging from interfering with phagocytosis and oxidative burst to iron acquisition. This study shows that the Mtb protein Rv0888 possesses potent sphingomyelinase activity cleaving sphingomyelin, a major lipid in eukaryotic cells, into ceramide and phosphocholine, which are then utilized by Mtb as carbon, nitrogen and phosphorus sources, respectively. An Mtb rv0888 deletion mutant did not grow on sphingomyelin as a sole carbon source anymore and replicated poorly in macrophages indicating that Mtb utilizes sphingomyelin during infection. Rv0888 is an unusual membrane protein with a surface-exposed C-terminal sphingomyelinase domain and a putative N-terminal channel domain that mediated glucose and phosphocholine uptake across the outer membrane in an M. smegmatis porin mutant. Hence, we propose to name Rv0888 as SpmT (sphingomyelinase of Mycobacterium tuberculosis). Erythrocyte membranes contain up to 27% sphingomyelin. The finding that Rv0888 accounts for half of Mtb's hemolytic activity is consistent with its sphingomyelinase activity and the observation that Rv0888 levels are increased in the presence of erythrocytes and sphingomyelin by 5- and 100-fold, respectively. Thus, Rv0888 is a novel outer membrane protein that enables Mtb to utilize sphingomyelin as a source of several essential nutrients during intracellular growth.
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Affiliation(s)
- Alexander Speer
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Jim Sun
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Olga Danilchanka
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Virginia Meikle
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Jennifer L Rowland
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Kerstin Walter
- Infection Immunology, Research Center Borstel, Borstel, Germany.,German Center for Infection Research, Borstel, Germany
| | - Bradford R Buck
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Mikhail Pavlenok
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Christoph Hölscher
- Infection Immunology, Research Center Borstel, Borstel, Germany.,German Center for Infection Research, Borstel, Germany.,Cluster of Excellence 'Inflammation at Interfaces', Christian-Albrechts-University, Kiel, Germany
| | - Sabine Ehrt
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, NY, USA
| | - Michael Niederweis
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, USA
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20
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Hydroxypropyl-β-cyclodextrin-mediated alterations in cell permeability, lipid and protein profiles of steroid-transforming Arthrobacter simplex. Appl Microbiol Biotechnol 2014; 99:387-97. [DOI: 10.1007/s00253-014-6089-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Revised: 09/08/2014] [Accepted: 09/10/2014] [Indexed: 10/24/2022]
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21
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Kigondu EM, Wasuna A, Warner DF, Chibale K. Pharmacologically active metabolites, combination screening and target identification-driven drug repositioning in antituberculosis drug discovery. Bioorg Med Chem 2014; 22:4453-61. [PMID: 24997576 DOI: 10.1016/j.bmc.2014.06.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Revised: 06/04/2014] [Accepted: 06/06/2014] [Indexed: 01/14/2023]
Abstract
There has been renewed interest in alternative strategies to address bottlenecks in antibiotic development. These include the repurposing of approved drugs for use as novel anti-infective agents, or their exploitation as leads in drug repositioning. Such approaches are especially attractive for tuberculosis (TB), a disease which remains a leading cause of morbidity and mortality globally and, increasingly, is associated with the emergence of drug-resistance. In this review article, we introduce a refinement of traditional drug repositioning and repurposing strategies involving the development of drugs that are based on the active metabolite(s) of parental compounds with demonstrated efficacy. In addition, we describe an approach to repositioning the natural product antibiotic, fusidic acid, for use against Mycobacterium tuberculosis. Finally, we consider the potential to exploit the chemical matter arising from these activities in combination screens and permeation assays which are designed to confirm mechanism of action (MoA), elucidate potential synergies in polypharmacy, and to develop rules for drug permeability in an organism that poses a special challenge to new drug development.
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Affiliation(s)
- Elizabeth M Kigondu
- Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa; South African Medical Research Council Drug Discovery and Development Research Unit, University of Cape Town, Rondebosch 7701, South Africa
| | - Antonina Wasuna
- Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa; South African Medical Research Council Drug Discovery and Development Research Unit, University of Cape Town, Rondebosch 7701, South Africa
| | - Digby F Warner
- Institute of Infectious Disease & Molecular Medicine, University of Cape Town, Rondebosch 7701, South Africa; MRC/NHLS/UCT Molecular Mycobacteriology Research Unit and DST/NRF Centre of Excellence for Biomedical Tuberculosis Research, Department of Clinical Laboratory Sciences, Faculty of Health Sciences, University of Cape Town, Rondebosch 7701, South Africa.
| | - Kelly Chibale
- Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa; South African Medical Research Council Drug Discovery and Development Research Unit, University of Cape Town, Rondebosch 7701, South Africa; Institute of Infectious Disease & Molecular Medicine, University of Cape Town, Rondebosch 7701, South Africa.
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22
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Xu WX, Zhang L, Mai JT, Peng RC, Yang EZ, Peng C, Wang HH. The Wag31 protein interacts with AccA3 and coordinates cell wall lipid permeability and lipophilic drug resistance in Mycobacterium smegmatis. Biochem Biophys Res Commun 2014; 448:255-60. [PMID: 24792177 DOI: 10.1016/j.bbrc.2014.04.116] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Accepted: 04/22/2014] [Indexed: 10/25/2022]
Abstract
Mycobacterium tuberculosis, especially drug resistant tuberculosis, is a serious threat to global human health. Compared with other bacterial pathogens, M. tuberculosis gains stronger natural drug resistance from its unusually lipid-rich cell wall. As a DivIVA homolog, Wag31 has been demonstrated to be closely involved in peptidoglycan synthesis, cell growth and cell division. Previous research rarely investigated the role of Wag31 in drug resistance. In this study, we found Wag31 knock-down in Mycobacterium smegmatis resulted in a co-decrease of the resistance to four lipophilic drugs (rifampicin, novobiocin, erythromycin and clofazimine) and an increase in the cell permeability to lipophilic molecules. Six proteins (AccA3, AccD4 and AccD5, Fas, InhA and MmpL3) that are involved in fatty acid and mycolic acid synthesis were identified in the Wag31 interactome through Co-Immunoprecipitation. The Wag31-AccA3 interaction was confirmed by the pull-down assay. AccA3 overexpression resulted in a decrease in lipid permeability and an increase in the resistance of rifampicin and novobiocin. It confirmed the close relationship of lipophilic drug resistance, lipid permeability and the Wag31-AccA3 interaction. These results demonstrated that Wag31 maintained the resistance to lipophilic drugs and that Wag31 could play a role in controlling the lipid permeability of the cell wall through the Wag31-AccA3 interaction.
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Affiliation(s)
- Wen-xi Xu
- State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Science, Fudan University, Shanghai, PR China.
| | - Lu Zhang
- State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Science, Fudan University, Shanghai, PR China.
| | - Jun-tao Mai
- State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Science, Fudan University, Shanghai, PR China.
| | - Ru-chao Peng
- State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Science, Fudan University, Shanghai, PR China.
| | - En-zhuo Yang
- State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Science, Fudan University, Shanghai, PR China.
| | - Chao Peng
- State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Science, Fudan University, Shanghai, PR China.
| | - Hong-hai Wang
- State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Science, Fudan University, Shanghai, PR China.
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23
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24
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25
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Machowski EE, Senzani S, Ealand C, Kana BD. Comparative genomics for mycobacterial peptidoglycan remodelling enzymes reveals extensive genetic multiplicity. BMC Microbiol 2014; 14:75. [PMID: 24661741 PMCID: PMC3987819 DOI: 10.1186/1471-2180-14-75] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2013] [Accepted: 03/12/2014] [Indexed: 02/04/2023] Open
Abstract
Background Mycobacteria comprise diverse species including non-pathogenic, environmental organisms, animal disease agents and human pathogens, notably Mycobacterium tuberculosis. Considering that the mycobacterial cell wall constitutes a significant barrier to drug penetration, the aim of this study was to conduct a comparative genomics analysis of the repertoire of enzymes involved in peptidoglycan (PG) remodelling to determine the potential of exploiting this area of bacterial metabolism for the discovery of new drug targets. Results We conducted an in silico analysis of 19 mycobacterial species/clinical strains for the presence of genes encoding resuscitation promoting factors (Rpfs), penicillin binding proteins, endopeptidases, L,D-transpeptidases and N-acetylmuramoyl-L-alanine amidases. Our analysis reveals extensive genetic multiplicity, allowing for classification of mycobacterial species into three main categories, primarily based on their rpf gene complement. These include the M. tuberculosis Complex (MTBC), other pathogenic mycobacteria and environmental species. The complement of these genes within the MTBC and other mycobacterial pathogens is highly conserved. In contrast, environmental strains display significant genetic expansion in most of these gene families. Mycobacterium leprae retains more than one functional gene from each enzyme family, underscoring the importance of genetic multiplicity for PG remodelling. Notably, the highest degree of conservation is observed for N-acetylmuramoyl-L-alanine amidases suggesting that these enzymes are essential for growth and survival. Conclusion PG remodelling enzymes in a range of mycobacterial species are associated with extensive genetic multiplicity, suggesting functional diversification within these families of enzymes to allow organisms to adapt.
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Affiliation(s)
| | | | | | - Bavesh Davandra Kana
- DST/NRF Centre of Excellence for Biomedical TB Research, Faculty of Health Sciences, University of the Witwatersrand, National Health Laboratory Service, P,O, Box 1038, Johannesburg 2000, South Africa.
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Islam MS, Richards JP, Ojha AK. Targeting drug tolerance in mycobacteria: a perspective from mycobacterial biofilms. Expert Rev Anti Infect Ther 2013; 10:1055-66. [PMID: 23106280 DOI: 10.1586/eri.12.88] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Multidrug chemotherapy for 6-9-months is one of the primary treatments in effective control of tuberculosis, although the mechanisms underlying the persistence of its etiological agent, Mycobacterium tuberculosis, against antibiotics remain unclear. Ever-mounting evidence indicates that the survival of many environmental and pathogenic microbial species against antibiotics is influenced by their ability to grow as surface-associated multicellular communities called biofilms. In recent years, several mycobacterial species, including M. tuberculosis, have been found to form drug-tolerant biofilms in vitro through genetically controlled mechanisms. In this review, the authors discuss the relevance of the in vitro mycobacterial biofilms in understanding the antibiotic recalcitrance of tuberculosis infections.
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Affiliation(s)
- Mohammad S Islam
- Department of Infectious Diseases and Microbiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA 15261, USA
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Ruiz N. A bird's eye view of the bacterial landscape. Methods Mol Biol 2013; 966:1-14. [PMID: 23299725 DOI: 10.1007/978-1-62703-245-2_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Bacteria interact with the environment through their cell surface. Activities as diverse as attaching to a catheter, crawling on a surface, swimming through a pond, or being preyed on by a bacteriophage depend on the composition and structure of the cell surface. The cell surface must also protect bacteria from harmful chemicals present in the environment while allowing the intake of nutrients and excretion of toxic molecules. Bacteria have evolved four main types of bacterial cell surfaces to accomplish these functions: those of the typical gram-negative and gram-positive bacteria, and those of the Actinobacteria and Mollicutes. So few types seems remarkable since bacteria are very diverse and abundant, and they can live in many different environments. However, each species has tweaked these stereotypical bacterial surfaces to best fit its needs. The result is an amazing diversity of the bacterial landscape, most of which remains unexplored. Here I give an overview of the main features of the bacterial cell surface and highlight how advances in methodology have moved forward this field of study.
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Affiliation(s)
- Natividad Ruiz
- Department of Microbiology, The Ohio State University, Columbus, OH, USA.
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Mycobacteriophage Ms6 LysA: a peptidoglycan amidase and a useful analytical tool. Appl Environ Microbiol 2012; 79:768-73. [PMID: 23160121 DOI: 10.1128/aem.02263-12] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Since the peptidoglycan isolated from Mycobacterium spp. is refractory to commercially available murolytic enzymes, possibly due to the presence of various modifications found on this peptidoglycan, the utility of a mycobacteriophage-derived murolytic enzyme was assessed for an analysis of peptidoglycan from mycobacteria. We cloned, expressed, and purified the lysA gene product, a protein with homology to known peptidoglycan-degrading amidases, from bacteriophage Ms6. The recombinant protein was shown to cleave the bond between l-Ala and d-muramic acid of muramyl pentapeptide and to release up to 70% of the diaminopimelic acid present in the isolated mycobacterial cell wall. In contrast to lysozyme, which, in culture, inhibits the growth of both Mycobacterium smegmatis and Mycobacterium tuberculosis, LysA had no effect on the growth of either species. However, the enzyme is useful for solubilizing the peptide chains of isolated mycobacterial peptidoglycan for analysis. The data indicate that the stem peptides from M. smegmatis are heavily amidated, containing few free carboxylic acids, regardless of the cross-linking status.
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Yang Y, Bhatti A, Ke D, Gonzalez-Juarrero M, Lenaerts A, Kremer L, Guerardel Y, Zhang P, Ojha AK. Exposure to a cutinase-like serine esterase triggers rapid lysis of multiple mycobacterial species. J Biol Chem 2012; 288:382-92. [PMID: 23155047 DOI: 10.1074/jbc.m112.419754] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Mycobacteria are shaped by a thick envelope made of an array of uniquely structured lipids and polysaccharides. However, the spatial organization of these molecules remains unclear. Here, we show that exposure to an esterase from Mycobacterium smegmatis (Msmeg_1529), hydrolyzing the ester linkage of trehalose dimycolate in vitro, triggers rapid and efficient lysis of Mycobacterium tuberculosis, Mycobacterium bovis BCG, and Mycobacterium marinum. Exposure to the esterase immediately releases free mycolic acids, while concomitantly depleting trehalose mycolates. Moreover, lysis could be competitively inhibited by an excess of purified trehalose dimycolate and was abolished by a S124A mutation affecting the catalytic activity of the esterase. These findings are consistent with an indispensable structural role of trehalose mycolates in the architectural design of the exposed surface of the mycobacterial envelope. Importantly, we also demonstrate that the esterase-mediated rapid lysis of M. tuberculosis significantly improves its detection in paucibacillary samples.
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Affiliation(s)
- Yong Yang
- Department of Infectious Diseases and Microbiology, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
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30
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Feril LB, Tachibana K. Use of ultrasound in drug delivery systems: emphasis on experimental methodology and mechanisms. Int J Hyperthermia 2012; 28:282-9. [PMID: 22621730 DOI: 10.3109/02656736.2012.668640] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Recent studies have shown that ultrasound energy could be applied for targeting or controlling drug release. This new concept of therapeutic ultrasound combined with drugs has induced a great amount of interest in various medical fields. In this paper, several experimental systems are cited in which ultrasound is being utilized to evaluate new application of this modality. The mechanisms of ultrasound-mediated drug delivery are discussed in addition to the review of current advances in the use of ultrasound in systems involving research in cancer therapy, gene therapy, microbubbles and other drug delivery in vitro and in vivo experiments.
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Affiliation(s)
- Loreto B Feril
- Department of Anatomy, Fukuoka University School of Medicine , 7-45-1 Nanakuma, Fukuoka 814-0180, Japan
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Jha DK, Panda L, Lavanya P, Ramaiah S, Anbarasu A. Detection and confirmation of alkaloids in leaves of Justicia adhatoda and bioinformatics approach to elicit its anti-tuberculosis activity. Appl Biochem Biotechnol 2012; 168:980-90. [PMID: 22899014 DOI: 10.1007/s12010-012-9834-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2012] [Accepted: 08/06/2012] [Indexed: 11/28/2022]
Abstract
The extraction and determination of alkaloids was performed and confirmed by phytochemical analysis. Six different quinazoline alkaloids (vasicoline, vasicolinone, vasicinone, vasicine, adhatodine and anisotine) were found in the leaf of Justicia adhatoda (J. adhatoda). The presence of the peaks obtained through HPLC indicated the diverse nature of alkaloid present in the leaf. The enzyme β-ketoacyl-acyl-carrier protein synthase III that catalyses the initial step of fatty acid biosynthesis (FabH) via a type II fatty acid synthase has unique structural features and universal occurrence in Mycobacterium tuberculosis (M. tuberculosis). Thus, it was considered as a target for designing of anti-tuberculosis compounds. Docking simulations were conducted on the above alkaloids derived from J. adhatoda. The combination of docking/scoring provided interesting insights into the binding of different inhibitors and their activity. These results will be useful for designing inhibitors for M. tuberculosis and also will be a good starting point for natural plant-based pharmaceutical chemistry.
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Affiliation(s)
- Deepak Kumar Jha
- Medical and Biological computing laboratory, School of Biosciences and Technology, VIT University, Vellore, India
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Effects of hydroxypropyl-β-cyclodextrin on cell growth, activity, and integrity of steroid-transforming Arthrobacter simplex and Mycobacterium sp. Appl Microbiol Biotechnol 2011; 90:1995-2003. [PMID: 21468712 DOI: 10.1007/s00253-011-3214-6] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2010] [Revised: 02/27/2011] [Accepted: 03/02/2011] [Indexed: 10/18/2022]
Abstract
A comparative investigation was performed on the effects of hydroxypropyl-β-cyclodextrin (HP-β-CD) on the growth, biocatalytic activity, and cell integrity of Arthrobacter simplex TCCC 11037 (ASP) and Mycobacterium sp. NRRL B-3683 (MSP). The addition of HP-β-CD to ASP medium improved its cell wall permeability for lipophilic compounds but significantly inhibited its growth and biocatalytic activity. On the other hand, the addition of HP-β-CD to MSP broth had lesser effects. Atomic force microscopy scanning analysis revealed that HP-β-CD damaged the cell integrity in ASP, especially the outermost cell surface structure, but not in MSP, which remained intact, owing to the differences in their cell wall and cell membrane composition. Protein leaking and lipid content in ASP increased with increased HP-β-CD concentration, indicating possible alterations in ASP cell membrane features caused by HP-β-CD. These alterations may also explain the slow cell growth and decreased cell ΔΨm in ASP upon the addition of HP-β-CD.
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Importance of porins for biocide efficacy against Mycobacterium smegmatis. Appl Environ Microbiol 2011; 77:3068-73. [PMID: 21398489 DOI: 10.1128/aem.02492-10] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mycobacteria are among the microorganisms least susceptible to biocides but cause devastating diseases, such as tuberculosis, and increasingly opportunistic infections. The exceptional resistance of mycobacteria to toxic solutes is due to an unusual outer membrane, which acts as an efficient permeability barrier, in synergy with other resistance mechanisms. Porins are channel-forming proteins in the outer membrane of mycobacteria. In this study we used the alamarBlue assay to show that the deletion of Msp porins in isogenic mutants increased the resistance of Mycobacterium smegmatis to isothiazolinones (methylchloroisothiazolinone [MCI]/methylisothiazolinone [MI] and octylisothiazolinone [2-n-octyl-4-isothiazolin-3-one; OIT]), formaldehyde-releasing biocides {hexahydrotriazine [1,3,5-tris (2-hydroxyethyl)-hexahydrotriazine; HHT] and methylenbisoxazolidine [N,N'-methylene-bis-5-(methyloxazolidine); MBO]}, and the lipophilic biocides polyhexamethylene biguanide and octenidine dihydrochloride 2- to 16-fold. Furthermore, the susceptibility of the porin triple mutant against a complex disinfectant was decreased 8-fold compared to wild-type (wt) M. smegmatis. Efficacy testing in the quantitative suspension test EN 14348 revealed 100-fold improved survival of the porin mutant in the presence of this biocide. These findings underline the importance of porins for the susceptibility of M. smegmatis to biocides.
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Kastrinsky DB, Barry CE. Synthesis of labeled meropenem for the analysis of M. tuberculosis transpeptidases. Tetrahedron Lett 2010; 51:197-200. [PMID: 20161438 DOI: 10.1016/j.tetlet.2009.10.124] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
A concise synthesis of (14)C labeled meropenem prepared from (14)C dimethylamine hydrochloride is described. Using a similar reaction sequence, the meropenem nucleus was also attached to biotin providing a probe for protein interaction studies.
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Affiliation(s)
- David B Kastrinsky
- The National Institutes of Health, National Institute of Allergy and Infectous Diseases, Tuberculosis Research Section, Bethesda MD 20892
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35
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Reconstitution experiments and gene deletions reveal the existence of two-component major cell wall channels in the genus Corynebacterium. J Bacteriol 2009; 192:786-800. [PMID: 19966008 DOI: 10.1128/jb.01142-09] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Two small polypeptides, PorA and PorH, are known to form cell wall channels in Corynebacterium glutamicum and in Corynebacterium efficiens. The genes coding for both polypeptides are localized in close proximity to one another between the genes coding for GroEl2 and a polyphosphate kinase (PKK2). In this study, we investigated the relationship of PorA and PorH to one another. The results suggested that the major cell wall channels of Corynebacterium glutamicum, Corynebacterium efficiens, and Corynebacterium diphtheriae need the obligatory presence of two distinct polypeptides, one of class PorA and one of class PorH, to form an active cell wall channel. Identification of genes coding for homologous proteins in the chromosome of Corynebacterium callunae suggested a similar result for this strain. Contrary to our previous reports on channel-forming proteins in these strains, a heterooligomeric structure composed of PorA and PorH is needed in all of them to form the major cell wall channel. This was concluded from complementation experiments using a porH- and porA-deficient C. glutamicum strain. The stringent necessity of proteins of either class to recover the wild-type channels was demonstrated by black lipid bilayer experiments using detergent or organic solvent extracts of the complemented porH- and porA-deficient C. glutamicum strain. The channel-forming capability of recombinant expressed, affinity-purified PorA and PorH proteins of C. glutamicum revealed that the channels consisted solely of these two components. This agreed with results obtained from a transcript coding for both channel-forming components identified in C. glutamicum by Northern blot analysis and reverse transcription-PCR analysis. The transcription start point of the genes was determined by the rapid amplification of cDNA ends approach, allowing the prediction of the -35 and -10 regions of the promoter. The results demonstrate that the cell wall channels within the genus Corynebacterium may be formed by two-component oligomers.
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Barry CE, Boshoff HI, Dartois V, Dick T, Ehrt S, Flynn J, Schnappinger D, Wilkinson RJ, Young D. The spectrum of latent tuberculosis: rethinking the biology and intervention strategies. Nat Rev Microbiol 2009; 7:845-55. [PMID: 19855401 PMCID: PMC4144869 DOI: 10.1038/nrmicro2236] [Citation(s) in RCA: 976] [Impact Index Per Article: 65.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Immunological tests provide evidence of latent tuberculosis in one third of the global population, which corresponds to more than two billion individuals. Latent tuberculosis is defined by the absence of clinical symptoms but carries a risk of subsequent progression to clinical disease, particularly in the context of co-infection with HIV. In this Review we discuss the biology of latent tuberculosis as part of a broad range of responses that occur following infection with Mycobacterium tuberculosis, which result in the formation of physiologically distinct granulomatous lesions that provide microenvironments with differential ability to support or suppress the persistence of viable bacteria. We then show how this model can be used to develop a rational programme to discover effective drugs for the eradication of M. tuberculosis infection.
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Affiliation(s)
- Clifton E Barry
- Tuberculosis Research Section, Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
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Sachdeva S, Musayev FN, Alhamadsheh MM, Scarsdale JN, Wright HT, Reynolds KA. Separate entrance and exit portals for ligand traffic in Mycobacterium tuberculosis FabH. ACTA ACUST UNITED AC 2008; 15:402-12. [PMID: 18420147 DOI: 10.1016/j.chembiol.2008.03.007] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2007] [Revised: 03/03/2008] [Accepted: 03/05/2008] [Indexed: 11/18/2022]
Abstract
Mycobacterium tuberculosis FabH initiates type II fatty acid synthase-catalyzed formation of the long chain (C(16)-C(22)) acyl-coenzyme A (CoA) precursors of mycolic acids, which are major constituents of the bacterial cell envelope. Crystal structures of M. tuberculosis FabH (mtFabH) show the substrate binding site to be a buried, extended L-shaped channel with only a single solvent access portal. Entrance of an acyl-CoA substrate through the solvent portal would require energetically unfavorable reptational threading of the substrate to its reactive position. Using a class of FabH inhibitors, we have tested an alternative hypothesis that FabH exists in an "open" form during substrate binding and product release, and a "closed" form in which catalysis and intermediate steps occur. This hypothesis is supported by mass spectrometric analysis of the product profile and crystal structures of complexes of mtFabH with these inhibitors.
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Affiliation(s)
- Sarbjot Sachdeva
- Department of Chemistry, Portland State University, Portland, OR 97207, USA
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38
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Dinadayala P, Sambou T, Daffé M, Lemassu A. Comparative structural analyses of the alpha-glucan and glycogen from Mycobacterium bovis. Glycobiology 2008; 18:502-8. [PMID: 18436565 DOI: 10.1093/glycob/cwn031] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Pathogenic mycobacteria such as Mycobacterium tuberculosis, the causative agent of tuberculosis, are surrounded by a noncovalently bound capsule, whose major carbohydrate constituent is a glycogen-like alpha-glucan. In the present study we compared the structures of the extracellular polysaccharide to that of the ubiquitous intracellular glycogen. The alpha-glucan was isolated from the culture medium of Mycobacterium bovis Bacille Calmette Guérin, the vaccine strain, in which it is released whereas the intracellular glycogen was obtained after the disruption of cells. The two purified polysaccharides were eluted from permeation gel at a similar position but glycogen was less soluble and gave a more opalescent solution in water than alpha-glucan. Combination of gas chromatography-mass spectrometry analysis of partially O-methylated, partially O-acetylated alditols and NMR analysis confirmed that both polysaccharides were composed of -->4-alpha-D-Glcp-1--> core, substituted at some six positions with short chains. Degradation of polysaccharides with pullulanase, followed by mass spectrometry analysis of the resulting products, also showed that the two polysaccharides do not differ in terms of lengths of branching. Interestingly, application of analytical ultracentrifugation and dynamic light scattering to the mycobacterial alpha-glucan and glycogen and their enzymatic degradative products indicated that the alpha-glucan possessed a higher molecular mass and was more compact than the glycogen from the same species, allowing the formulation of working structural models for the two polysaccharides. Consistent with the models, the alpha-glucan was found to be less accessible to pullulanase, a debranching enzyme, than glycogen.
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Affiliation(s)
- Premkumar Dinadayala
- Département Mécanismes Moléculaires des Infections Mycobactériennes, Institut de Pharmacologie et Biologie Structurale (UMR 5089), Université Paul Sabatier (Toulouse III), Centre National de la Recherche Scientifique, 205, 31077 Toulouse cedex, France
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Donova MV, Nikolayeva VM, Dovbnya DV, Gulevskaya SA, Suzina NE. Methyl-beta-cyclodextrin alters growth, activity and cell envelope features of sterol-transforming mycobacteria. MICROBIOLOGY-SGM 2007; 153:1981-1992. [PMID: 17526855 DOI: 10.1099/mic.0.2006/001636-0] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Modified beta-cyclodextrins have been shown previously to enhance sterol conversion to 4-androstene-3,17-dione (AD) and 1,4-androstadiene-3,17-dione (ADD) by growing Mycobacterium spp. The enhancement effect was mainly attributed to steroid solubilization by the formation of inclusion complexes with modified cyclodextrins. In this work, the influence of randomly methylated beta-cyclodextrin (MCD) on the growth, AD- and ADD-producing activity, cell wall (CW) composition and ultrastructure of sterol-transforming Mycobacterium sp. VKM Ac-1816D was studied. The specific growth rate of the strain on glycerol increased in the presence of MCD (20-100 mM). Washed cells grown in the presence of MCD (20-40 mM) expressed 1.6-fold higher ADD-producing activity than did the cells grown without MCD, and their adhesiveness differed. Electron microscopy showed MCD-mediated CW exfoliation and accumulation of membrane-like structures outside the cells, while preserving cells intact. The analysis of CW composition revealed both a decrease in the proportion of extractable lipids and a considerable shift in fatty acid profile resulting from MCD action. The MCD-mediated enhancement of mycolic and fatty acids content was observed outside the cells. The total secreted protein level rose 2.4-fold, and the extracellular 3-hydroxysteroid oxidase activity 3.2-fold. The composition of the CW polysaccharide was not altered, while the overall proportion of the carbohydrates in the CW of the MCD-exposed mycobacteria increased. The results showed that the multiple mechanisms of MCD-mediated intensification of sterol to AD(D) conversion by mycobacteria include not only solubilization of steroids, but also the increase of CW permeability for both steroids and soluble nutrients, disorganization of the lipid bilayer and the release of steroid-transforming enzymes weakly associated with the CW.
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Affiliation(s)
- M V Donova
- G. K. Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, 142290, Pushchino, Moscow Region, Russia
| | - V M Nikolayeva
- G. K. Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, 142290, Pushchino, Moscow Region, Russia
| | - D V Dovbnya
- G. K. Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, 142290, Pushchino, Moscow Region, Russia
| | - S A Gulevskaya
- G. K. Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, 142290, Pushchino, Moscow Region, Russia
| | - N E Suzina
- G. K. Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, 142290, Pushchino, Moscow Region, Russia
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40
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Schiffler B, Barth E, Daffé M, Benz R. Corynebacterium diphtheriae: identification and characterization of a channel-forming protein in the cell wall. J Bacteriol 2007; 189:7709-19. [PMID: 17720794 PMCID: PMC2168714 DOI: 10.1128/jb.00864-07] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2007] [Accepted: 08/10/2007] [Indexed: 11/20/2022] Open
Abstract
The cell wall fraction of the gram-positive, nontoxic Corynebacterium diphtheriae strain C8r(-) Tox- (=ATCC 11913) contained a channel-forming protein, as judged from reconstitution experiments with artificial lipid bilayer experiments. The channel-forming protein was present in detergent-treated cell walls and in extracts of whole cells obtained using organic solvents. The protein had an apparent molecular mass of about 66 kDa as determined on Tricine-containing sodium dodecyl sulfate-polyacrylamide gel electrophoresis gels and consisted of subunits having a molecular mass of about 5 kDa. Single-channel experiments with the purified protein suggested that the protein formed channels with a single-channel conductance of 2.25 nS in 1 M KCl. Further single-channel analysis suggested that the cell wall channel is wide and water filled because it has only slight selectivity for cations over anions and its conductance followed the mobility sequence of cations and anions in the aqueous phase. Antibodies raised against PorA, the subunit of the cell wall channel of Corynebacterium glutamicum, detected both monomers and oligomers of the isolated protein, suggesting that there are highly conserved epitopes in the cell wall channels of C. diphtheriae and PorA. Localization of the protein on the cell surface was confirmed by an enzyme-linked immunosorbent assay. The prospective homology of PorA with the cell wall channel of C. diphtheriae was used to identify the cell wall channel gene, cdporA, in the known genome of C. diphtheriae. The gene and its flanking regions were cloned and sequenced. CdporA is a protein that is 43 amino acids long and does not have a leader sequence. cdporA was expressed in a C. glutamicum strain that lacked the major outer membrane channels PorA and PorH. Organic solvent extracts of the transformed cells formed in lipid bilayer membranes the same channels as the purified CdporA protein of C. diphtheriae formed, suggesting that the expressed protein is able to complement the PorA and PorH deficiency of the C. glutamicum strain. The study is the first report of a cell wall channel in a pathogenic Corynebacterium strain.
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Affiliation(s)
- Bettina Schiffler
- Lehrstuhl für Biotechnologie, Biozentrum der Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
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Cangelosi GA, Do JS, Freeman R, Bennett JG, Semret M, Behr MA. The two-component regulatory system mtrAB is required for morphotypic multidrug resistance in Mycobacterium avium. Antimicrob Agents Chemother 2006; 50:461-8. [PMID: 16436697 PMCID: PMC1366905 DOI: 10.1128/aac.50.2.461-468.2006] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Clinical isolates of the opportunistic pathogen Mycobacterium avium complex (MAC) undergo a reversible switch between red and white colony morphotypes on agar plates containing the lipoprotein stain Congo red. Compared to their isogenic red counterparts, white morphotypic variants are more virulent and more resistant to multiple antibiotics. This report shows that the two-component regulatory system mtrAB is required for the red-to-white switch as well as for other morphotypic switches of MAC. A mutant with a transposon insertion in the histidine protein kinase gene mtrB was isolated from a morphotypically white parent clone. The mutant resembled a naturally occurring red morphotypic variant in that it stained with Congo red, was sensitive to multiple antibiotics, and was permeable by a fluorescent DNA stain. However, it differed from a red variant in that it could not switch to the white or transparent morphotype, and it could not survive intracellularly within macrophage-like cells. Transcomplementation with a cloned wild-type mtrB gene restored to the mutant the ability to form impermeable, drug-resistant white and transparent variants. Quantitative reverse transcriptase PCR showed that mtrB was required for the normal expression of cell surface Mce proteins, some of which are up-regulated in the red-to-white switch. The results indicate that mtrAB functions in regulating the composition and permeability of mycobacterial cell walls and plays a role in the reversible colony type switches of MAC.
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Affiliation(s)
- Gerard A Cangelosi
- Seattle Biomedical Research Institute, 307 Westlake Avenue N., Suite 500, Seattle, WA 98109, USA.
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42
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Hong X, Hopfinger AJ. Construction, molecular modeling, and simulation of Mycobacterium tuberculosis cell walls. Biomacromolecules 2005; 5:1052-65. [PMID: 15132700 DOI: 10.1021/bm034514c] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The mycobacterial cell wall is extraordinarily thick and tight consisting mainly of (1). long chain fatty acids, the mycolic acids, and (2). a unique polysaccharide, arabinogalactan (AG). These two chemical constituents are covalently linked through ester bonds. Minnikin (The Biology of the Mycobacteria; Academic: London, 1982) proposed that the mycobacterial cell wall is composed of an asymmetric lipid bilayer. The inner leaflet of the cell wall contains mycolic acids covalently linked to AG. This inner leaflet is believed to have the lowest permeability to organic compounds of the overall cell wall. Conformational search and molecular dynamics simulation were used to explore the conformational profile of AG and the conformations and structural organization of the mycolic acid-AG complex, and overall, an inner leaflet molecular model of the cell wall was constructed. The terminal arabinose residues of AG that serve as linkers between AG and mycolic acids were found to exist in four major chemical configurations. The mycolate hydrocarbon chains were determined to be tightly packed and perpendicular to the "plane" formed by the oxygen atoms of the 5-hydroxyl groups of the terminal arabinose residues. For Mycobacterium tuberculosis, the average packing distance between mycolic acids is estimated to be approximately 7.3 A. Thus, Minnikin's model is supported by this computational study. Overall, this modeling and simulation approach provides a way to probe the mechanism of low permeability of the cell wall and the intrinsic drug resistance of M. tuberculosis. In addition, monolayer models were built for both dipalmitoylphosphatidylethanolamine and dimyristoylphosphatidylcholine, two common phospholipids in bacterial and animal membranes, respectively. Structural comparisons of these cell wall phospholipid membrane models were made to the M. tuberculosis cell wall model.
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Affiliation(s)
- Xuan Hong
- Laboratory of Molecular Modeling and Design (MC 781), College of Pharmacy, The University of Illinois at Chicago, 833 South Wood Street, Chicago, Illinois 60612-7231, USA
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Dörner U, Maier E, Benz R. Identification of a cation-specific channel (TipA) in the cell wall of the gram-positive mycolata Tsukamurella inchonensis: the gene of the channel-forming protein is identical to mspA of Mycobacterium smegmatis and mppA of Mycobacterium phlei. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2004; 1667:47-55. [PMID: 15533305 DOI: 10.1016/j.bbamem.2004.09.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2004] [Revised: 09/01/2004] [Accepted: 09/02/2004] [Indexed: 11/30/2022]
Abstract
Detergent extracts of whole cells of the Gram-positive bacterium Tsukamurella inchonensis ATCC 700082, which belongs to the mycolata, were studied for the presence of ion-permeable channels using lipid bilayer experiments. One channel with a conductance of about 4.5 nS in 1 M KCl was identified in the extracts. The channel-forming protein was purified to homogeneity by preparative SDS-PAGE. The protein responsible for channel-forming activity had an apparent molecular mass of about 33 kDa as judged by SDS-PAGE. Interestingly, the protein showed cross-reactivity with polyclonal antibodies raised against a polypeptide derived from MspA of Mycobacterium smegmatis similarly as the cell wall channel of Mycobacterium phlei. Primers derived from mspA were used to clone and sequence the gene of the cell wall channels of T. inchonensis (named tipA for T. inchonensis porin A) and M. phlei (named mppA for M. phlei porin A). Surprisingly, both genes, tipA and mppA, were found to be identical to mspA of M. smegmatis, indicating that the genomes of T. inchonensis, M. phlei and M. smegmatis contain the same genes for the major cell wall channel. RT-PCR revealed that tipA is transcribed in T. inchonensis and mppA in M. phlei. The results suggest that despite a certain distance between the three organisms, their genomes contain the same gene coding for the major cell wall channel, with a molecular mass of 22 kDa for the monomer.
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Affiliation(s)
- Ursula Dörner
- Lehrstuhl für Biotechnologie, Biozentrum der Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
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44
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Philalay JS, Palermo CO, Hauge KA, Rustad TR, Cangelosi GA. Genes required for intrinsic multidrug resistance in Mycobacterium avium. Antimicrob Agents Chemother 2004; 48:3412-8. [PMID: 15328105 PMCID: PMC514743 DOI: 10.1128/aac.48.9.3412-3418.2004] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Genes required for intrinsic multidrug resistance by Mycobacterium avium were identified by screening a library of transposon insertion mutants for the inability to grow in the presence of ciprofloxacin, clarithromycin, and penicillin at subinhibitory concentrations. Two genes, pks12 and Maa2520, were disrupted in multiple drug-susceptible mutants. The pks12 gene (Maa1979), which may be cotranscribed with a downstream gene (Maa1980), is widely conserved in the actinomycetes. Its ortholog in Mycobacterium tuberculosis is a polyketide synthase required for the synthesis of dimycocerosyl phthiocerol, a major cell wall lipid. Mutants of M. avium with insertions into pks12 exhibited altered colony morphology and were drug susceptible, but they grew as well as the wild type did in vitro and intracellularly within THP-1 cells. A pks12 mutant of M. tuberculosis was moderately more susceptible to clarithromycin than was its parent strain; however, susceptibility to ciprofloxacin and penicillin was not altered. M. avium complex (MAC) and M. tuberculosis appear to have different genetic mechanisms for resisting the effects of these antibiotics, with pks12 playing a relatively more significant role in MAC. The second genetic locus identified in this study, Maa2520, is a conserved hypothetical gene with orthologs in M. tuberculosis and Mycobacterium leprae. It is immediately upstream of Maa2521, which may code for an exported protein. Mutants with insertions at this locus were susceptible to multiple antibiotics and slow growing in vitro and were unable to survive intracellularly within THP-1 cells. Like pks12 mutants, they exhibited increased Congo red binding, an indirect indication of cell wall modifications. Maa2520 and pks12 are the first genes to be linked by mutation to intrinsic drug resistance in MAC.
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Affiliation(s)
- Julie S Philalay
- Seattle Biomedical Research Institute, 4 Nickerson St., Seattle, WA 98109, USA
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45
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Mailaender C, Reiling N, Engelhardt H, Bossmann S, Ehlers S, Niederweis M. The MspA porin promotes growth and increases antibiotic susceptibility of both Mycobacterium bovis BCG and Mycobacterium tuberculosis. MICROBIOLOGY-SGM 2004; 150:853-864. [PMID: 15073295 DOI: 10.1099/mic.0.26902-0] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Porins mediate the diffusion of hydrophilic solutes across the outer membrane of mycobacteria, but the efficiency of this pathway is very low compared to Gram-negative bacteria. To examine the importance of porins in slow-growing mycobacteria, the major porin MspA of Mycobacterium smegmatis was expressed in Mycobacterium tuberculosis and Mycobacterium bovis. Approximately 20 and 35 MspA molecules per microm(2) cell wall were observed in M. tuberculosis and M. bovis BCG, respectively, by electron microscopy and quantitative immunoblot experiments. Surface accessibility of MspA in M. tuberculosis was demonstrated by flow cytometry. Glucose uptake was twofold faster, indicating that the outer membrane permeability of M. bovis BCG to small and hydrophilic solutes was increased by MspA. This significantly accelerated the growth of M. bovis BCG, identifying very slow nutrient uptake as one of the determinants of slow growth in mycobacteria. The susceptibility of both M. bovis BCG and M. tuberculosis to zwitterionic beta-lactam antibiotics was substantially enhanced by MspA, decreasing the minimal inhibitory concentration up to 16-fold. Furthermore, M. tuberculosis became significantly more susceptible to isoniazid, ethambutol and streptomycin. Fluorescence with the nucleic acid binding dye SYTO 9 was 10-fold increased upon expression of mspA. These results indicated that MspA not only enhanced the efficiency of the porin pathway, but also that of pathways mediating access to large and/or hydrophobic agents. This study provides the first experimental evidence that porins are important for drug susceptibility of M. tuberculosis.
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Affiliation(s)
- Claudia Mailaender
- Lehrstuhl für Mikrobiologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstr 5, D-91058 Erlangen, Germany
| | - Norbert Reiling
- Molekulare Infektiologie, Forschungszentrum Borstel, Parkallee 22, D-23845 Borstel, Germany
| | - Harald Engelhardt
- Max-Planck-Institut für Biochemie, Abteilung Molekulare Strukturbiologie, Am Klopferspitz 18, D-82152 Martinsried, Germany
| | - Stefan Bossmann
- Lehrstuhl für Umweltmesstechnik, Universität Karlsruhe, Engler-Bunte-Ring 1, D-76128 Karlsruhe, Germany
| | - Stefan Ehlers
- Molekulare Infektiologie, Forschungszentrum Borstel, Parkallee 22, D-23845 Borstel, Germany
| | - Michael Niederweis
- Lehrstuhl für Mikrobiologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstr 5, D-91058 Erlangen, Germany
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46
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Wiker HG. Liberation of soluble proteins from live and dead mycobacterial cells and the implications for pathogenicity of tubercle bacilli hypothesis. Scand J Immunol 2001; 54:82-6. [PMID: 11439152 DOI: 10.1046/j.1365-3083.2001.00946.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Soluble proteins liberated from live M. tuberculosis are translocated through the cytoplasmic membrane to a 'periplasmic space'. For further export of proteins across the outer permeability barrier, it is necessary to postulate an excretion mechanism possibly involving some kind of porin. Observations of the repertoire of proteins in culture filtrates after liquid culture of M. tuberculosis show that a large repertoire of various kinds of proteins cross the outer permeability barrier of tubercle bacilli indicating that the excretion mechanism has a wide range of specificities for proteins. Culture filtrates of tubercle bacilli almost always contain both truly secreted proteins and cytoplasmatically-derived proteins. It is questionable whether cytoplasmic proteins can cross an intact cytoplasmic membrane. The simplest explanation for the appearance of cytoplasmic proteins in culture filtrates of tubercle bacilli would be that they are released after disintegration of the cytoplasmic membrane in dying or dead bacilli. Tubercle bacilli armed with secreted factors that may specifically inhibit innate and adaptive immune responses, excrete these from the periplasmic space of live bacilli. Unspecific in its character, the excretion mechanism also liberates proteins that are essential for building and maintaining the cell wall, thereby reducing the effectiveness of this process. This may be part of the explanation why M. tuberculosis and other pathogenic mycobacteria grow so slowly. Finally, it may be postulated that dormant or latent tubercle bacilli use their repertoire of secreted proteins to control their intracellular habitat and that bacterial cytoplasmic proteins would not be liberated from such bacilli. The consequence would be that only immune responses to secreted proteins would be effective for elimination of the dormant stage of infection. In a situation with active infection there will be considerable growth and turnover of bacilli with liberation of all kinds of immunogenic substances from the bacilli. In this situation immunity against cytoplasmic proteins would also be effective and immunity to cytoplasmic proteins should also be effective for control of the reactivation of latent disease because as soon as the bacilli start to grow there will also be a subpopulation of dead bacilli on the arena.
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Affiliation(s)
- H G Wiker
- National Institute of Public Health, Department of Environmental Medicine, P.O. Box 4404, Nydalen, N-0403 Oslo, Norway
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47
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Beatty WL, Rhoades ER, Ullrich HJ, Chatterjee D, Heuser JE, Russell DG. Trafficking and release of mycobacterial lipids from infected macrophages. Traffic 2000; 1:235-47. [PMID: 11208107 DOI: 10.1034/j.1600-0854.2000.010306.x] [Citation(s) in RCA: 265] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Analysis of infected macrophages revealed that lipid-containing moieties of the mycobacterial cell wall are actively trafficked out of the mycobacterial vacuole. To facilitate the analysis of vesicular trafficking from mycobacteria-containing phagosomes, surface-exposed carbohydrates were labeled with hydrazide-tagged markers. The distribution of labeled carbohydrate/lipid moieties and subsequent interaction with cellular compartments were analyzed by immunoelectron microscopy and by fluorescence microscopy of live cells. The released mycobacterial constituents were associated with several intracellular organelles and were enriched strikingly in tubular endocytic compartments. Subcellular fractionation of infected macrophages by density gradient electrophoresis showed temporal movement of labeled bacterial constituents through early and late endosomes. Thin layer chromatography analysis of these subcellular fractions confirmed their lipid nature and revealed five dominant bacteria-derived species. These mycobacterial lipids were also found in extracellular vesicles isolated from the medium and could be observed in un-infected 'bystander' cells. Their transfer to bystander cells could expand the bacteria's sphere of influence beyond the immediate confines of the host cell.
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Affiliation(s)
- W L Beatty
- Department of Molecular Microbiology, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, USA
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48
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Bhatt A, Green R, Coles R, Condon M, Connell ND. A mutant of Mycobacterium smegmatis defective in dipeptide transport. J Bacteriol 1998; 180:6773-5. [PMID: 9852030 PMCID: PMC107789 DOI: 10.1128/jb.180.24.6773-6775.1998] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A mutant of Mycobacterium smegmatis unable to use the dipeptide carnosine (beta-alanyl-L-histidine) as a sole carbon or nitrogen source was isolated. Carnosinase activity and the ability to grow on beta-Ala and/or L-His were similar in the mutant and the wild type. However, the mutant showed significant impairment in the uptake of carnosine. This study is the first description of a peptide utilization mutant of a mycobacterium.
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Affiliation(s)
- A Bhatt
- Department of Microbiology and Molecular Genetics, and Department of Surgery, UMDNJ/New Jersey Medical School, Newark, New Jersey 07103, USA
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49
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Riess FG, Lichtinger T, Cseh R, Yassin AF, Schaal KP, Benz R. The cell wall porin of Nocardia farcinica: biochemical identification of the channel-forming protein and biophysical characterization of the channel properties. Mol Microbiol 1998; 29:139-50. [PMID: 9701809 DOI: 10.1046/j.1365-2958.1998.00914.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A channel-forming protein was identified in cell wall extracts of the Gram-positive, strictly aerobic bacterium Nocardia farcinica. The cell wall porin was purified to homogeneity and had an apparent molecular mass of about 87 kDa on tricine-containing SDS-PAGE. When the 87 kDa protein was boiled for a longer time in sodium dodecylsulphate (SDS) it dissociated into two subunits with molecular masses of about 19 and 23 kDa. The 87 kDa form of the protein was able to increase the specific conductance of artificial lipid bilayer membranes from phosphatidylcholine (PC) phosphatidylserine (PS) mixtures by the formation of ion-permeable channels. The channels had on average a single-channel conductance of 3.0 nS in 1M KCl, 10mM Tris-HCl, pH8, and were found to be cation selective. Asymmetric addition of the cell wall porin to lipid bilayer membranes resulted in an asymmetric voltage dependence. The single-channel conductance was only moderately dependent on the bulk aqueous KCl concentration, which indicated point charge effects on the channel properties. The analysis of the single-channel conductance data in different salt solutions using the Renkin correction factor, and the effect of negative charges on channel conductance suggested that the diameter of the cell wall porin is about 1.4-1.6nm. Channel-forming properties of the cell wall porin of N. farcinica were compared with those of mycobacteria and corynebacteria. The cell wall porins of these members of the order Actinomycetales share common features because they form large and water-filled channels that contain negative point charges.
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Affiliation(s)
- F G Riess
- Lehrstuhl für Biotechnologie, Biozentrum der Universität Würzburg, Germany
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50
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Abstract
Drug-resistant tuberculosis remains a worldwide problem. New laboratory methods have improved our ability to more rapidly identify resistant strains, but the most effective approach is to prevent the appearance of resistance by appropriate choice of antibiotics and directly-observed therapy. Mycobacterium tuberculosis is treated with familiar and unique drugs; consequently, mechanisms of resistance have some unique features. All drug resistance thus far identified develops by mutational events rather than acquisition of resistance genes from other bacteria. An agenda is presented for countering the appearance of further drug resistance in mycobacteria.
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Affiliation(s)
- L M Parsons
- Division of Infectious Disease, Wadsworth Center, New York State Department of Health, Albany, USA
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