1
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Franklin A, Salgueiro VC, Layton AJ, Sullivan R, Mize T, Vázquez-Iniesta L, Benedict ST, Gurcha SS, Anso I, Besra GS, Banzhaf M, Lovering AL, Williams SJ, Guerin ME, Scott NE, Prados-Rosales R, Lowe EC, Moynihan PJ. The mycobacterial glycoside hydrolase LamH enables capsular arabinomannan release and stimulates growth. Nat Commun 2024; 15:5740. [PMID: 38982040 PMCID: PMC11233589 DOI: 10.1038/s41467-024-50051-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Accepted: 06/26/2024] [Indexed: 07/11/2024] Open
Abstract
Mycobacterial glycolipids are important cell envelope structures that drive host-pathogen interactions. Arguably, the most important are lipoarabinomannan (LAM) and its precursor, lipomannan (LM), which are trafficked from the bacterium to the host via unknown mechanisms. Arabinomannan is thought to be a capsular derivative of these molecules, lacking a lipid anchor. However, the mechanism by which this material is generated has yet to be elucidated. Here, we describe the identification of a glycoside hydrolase family 76 enzyme that we term LamH (Rv0365c in Mycobacterium tuberculosis) which specifically cleaves α-1,6-mannoside linkages within LM and LAM, driving its export to the capsule releasing its phosphatidyl-myo-inositol mannoside lipid anchor. Unexpectedly, we found that the catalytic activity of this enzyme is important for efficient exit from stationary phase cultures, potentially implicating arabinomannan as a signal for growth phase transition. Finally, we demonstrate that LamH is important for M. tuberculosis survival in macrophages.
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Affiliation(s)
- Aaron Franklin
- School of Biosciences, University of Birmingham, Birmingham, UK
| | - Vivian C Salgueiro
- Department of Preventive Medicine, Public Health and Microbiology, School of Medicine, Universidad Autonoma de Madrid, Madrid, Spain
| | | | - Rudi Sullivan
- School of Biosciences, University of Birmingham, Birmingham, UK
| | - Todd Mize
- School of Biosciences, University of Birmingham, Birmingham, UK
| | - Lucía Vázquez-Iniesta
- Department of Preventive Medicine, Public Health and Microbiology, School of Medicine, Universidad Autonoma de Madrid, Madrid, Spain
| | | | | | - Itxaso Anso
- Structural Glycobiology Laboratory, Department of Structural and Molecular Biology, Molecular Biology Institute of Barcelona, Spanish National Research Council, Barcelona Science Park, c/Baldiri Reixac 10-12, Tower R, 08028, Barcelona, Catalonia, Spain
| | - Gurdyal S Besra
- School of Biosciences, University of Birmingham, Birmingham, UK
| | - Manuel Banzhaf
- School of Biosciences, University of Birmingham, Birmingham, UK
| | | | - Spencer J Williams
- School of Chemistry and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC, Australia
| | - Marcelo E Guerin
- Structural Glycobiology Laboratory, Department of Structural and Molecular Biology; Molecular Biology Institute of Barcelona (IBMB), Spanish National Research Council (CSIC), Barcelona, Catalonia, Spain
| | - Nichollas E Scott
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, Australia
| | - Rafael Prados-Rosales
- Department of Preventive Medicine, Public Health and Microbiology, School of Medicine, Universidad Autonoma de Madrid, Madrid, Spain
| | - Elisabeth C Lowe
- Newcastle University Biosciences Institute, Medical School, Newcastle University, Newcastle upon Tyne, UK.
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2
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Kitzmiller CE, Cheng TY, Prandi J, Sparks IL, Moody DB, Morita YS. Detergent-induced quantitatively limited formation of diacyl phosphatidylinositol dimannoside in Mycobacterium smegmatis. J Lipid Res 2024; 65:100533. [PMID: 38522749 PMCID: PMC11269278 DOI: 10.1016/j.jlr.2024.100533] [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] [Received: 01/21/2024] [Revised: 03/16/2024] [Accepted: 03/19/2024] [Indexed: 03/26/2024] Open
Abstract
Mycobacterial plasma membrane, together with the peptidoglycan-arabinogalactan cell wall and waxy outer membrane, creates a robust permeability barrier against xenobiotics. The fact that several antituberculosis drugs target plasma membrane-embedded enzymes underscores the importance of the plasma membrane in bacterial physiology and pathogenesis. Nevertheless, its accurate phospholipid composition remains undefined, with conflicting reports on the abundance of phosphatidylinositol mannosides (PIMs), physiologically important glycolipids evolutionarily conserved among mycobacteria and related bacteria. Some studies indicate cardiolipin, phosphatidylethanolamine, and phosphatidylinositol as dominant structural phospholipids. Conversely, some suggest PIMs dominate the plasma membrane. A striking example of the latter is the use of reverse micelle extraction, showing diacyl phosphatidylinositol dimannoside (Ac2PIM2) as the most abundant phospholipid in a model organism, Mycobacterium smegmatis. Our recent work reveals a rapid response mechanism to membrane-fluidizing stress in mycobacterial plasma membrane: monoacyl phosphatidylinositol dimannoside and hexamannoside (AcPIM2 and AcPIM6) are converted to diacyl forms (Ac2PIM2 and Ac2PIM6). Given the dynamic nature of PIMs, we aimed to resolve the conflicting data in the literature. We show that unstressed M. smegmatis lacks an Ac2PIM2-dominated plasma membrane. Ac2PIM2 accumulation is induced by experimental conditions involving sodium docusate, a component of the reverse micellar solution. Using chemically synthesized PIMs as standards, we accurately quantified phospholipid ratio in M. smegmatis through liquid chromatography-mass spectrometry, revealing that mycobacterial plasma membrane is dominated by cardiolipin, phosphatidylethanolamine, and phosphatidylinositol. PIMs are quantitatively minor but responsive to environmental stresses in M. smegmatis. Our study paves the way for accurate modeling of mycobacterial plasma membrane.
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Affiliation(s)
| | - Tan-Yun Cheng
- Division of Rheumatology, Immunity and Inflammation, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Jacques Prandi
- Institut de Pharmacologie et de Biologie Structurale, CNRS, UPS, Université de Toulouse, Toulouse, France
| | - Ian L Sparks
- Department of Microbiology, University of Massachusetts, Amherst, MA, USA
| | - D Branch Moody
- Division of Rheumatology, Immunity and Inflammation, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Yasu S Morita
- Department of Microbiology, University of Massachusetts, Amherst, MA, USA.
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3
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van der Klugt T, van den Biggelaar RHGA, Saris A. Host and bacterial lipid metabolism during tuberculosis infections: possibilities to synergise host- and bacteria-directed therapies. Crit Rev Microbiol 2024:1-21. [PMID: 38916142 DOI: 10.1080/1040841x.2024.2370979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2024] [Revised: 06/10/2024] [Accepted: 06/11/2024] [Indexed: 06/26/2024]
Abstract
Mycobacterium tuberculosis (Mtb) is the causative pathogen of tuberculosis, the most lethal infectious disease resulting in 1.3 million deaths annually. Treatments against Mtb are increasingly impaired by the growing prevalence of antimicrobial drug resistance, which necessitates the development of new antibiotics or alternative therapeutic approaches. Upon infecting host cells, predominantly macrophages, Mtb becomes critically dependent on lipids as a source of nutrients. Additionally, Mtb produces numerous lipid-based virulence factors that contribute to the pathogen's ability to interfere with the host's immune responses and to create a lipid rich environment for itself. As lipids, lipid metabolism and manipulating host lipid metabolism play an important role for the virulence of Mtb, this review provides a state-of-the-art overview of mycobacterial lipid metabolism and concomitant role of host metabolism and host-pathogen interaction therein. While doing so, we will emphasize unexploited bacteria-directed and host-directed drug targets, and highlight potential synergistic drug combinations that hold promise for the development of new therapeutic interventions.
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Affiliation(s)
- Teun van der Klugt
- Department of Infectious Diseases, Leiden University Medical Center, Leiden, The Netherlands
| | | | - Anno Saris
- Department of Infectious Diseases, Leiden University Medical Center, Leiden, The Netherlands
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4
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Bhattacharje G, Ghosh A, Das AK. Deciphering the mannose transfer mechanism of mycobacterial PimE by molecular dynamics simulations. Glycobiology 2024; 34:cwad096. [PMID: 38039077 DOI: 10.1093/glycob/cwad096] [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] [Received: 10/04/2023] [Revised: 11/21/2023] [Accepted: 11/27/2023] [Indexed: 12/03/2023] Open
Abstract
Phosphatidyl-myo-inositol mannosides (PIMs), Lipomannan (LM), and Lipoarabinomannan (LAM) are essential components of the cell envelopes of mycobacteria. At the beginning of the biosynthesis of these compounds, phosphatidylinositol (PI) is mannosylated and acylated by various enzymes to produce Ac1/2PIM4, which is used to synthesize either Ac1/2PIM6 or LM/LAM. The protein PimE, a membrane-bound glycosyltransferase (GT-C), catalyzes the addition of a mannose group to Ac1PIM4 to produce Ac1PIM5, using polyprenolphosphate mannose (PPM) as the mannose donor. PimE-deleted Mycobacterium smegmatis (Msmeg) showed structural deformity and increased antibiotic and copper sensitivity. Despite knowing that the mutation D58A caused inactivity in Msmeg, how PimE catalyzes the transfer of mannose from PPM to Ac1/2PIM4 remains unknown. In this study, analyzing the AlphaFold structure of PimE revealed the presence of a tunnel through the D58 residue with two differently charged gates. Molecular docking suggested PPM binds to the hydrophobic tunnel gate, whereas Ac1PIM4 binds to the positively charged tunnel gate. Molecular dynamics (MD) simulations further demonstrated the critical roles of the residues N55, F87, L89, Y163, Q165, K197, L198, R251, F277, W324, H326, and I375 in binding PPM and Ac1PIM4. The mutation D58A caused a faster release of PPM from the catalytic tunnel, explaining the loss of PimE activity. Along with a hypothetical mechanism of mannose transfer by PimE, we also observe the presence of tunnels through a negatively charged aspartate or glutamate with two differently-charged gates among most GT-C enzymes. Common hydrophobic gates of GT-C enzymes probably harbor sugar donors, whereas, differently-charged tunnel gates accommodate various sugar-acceptors.
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Affiliation(s)
- Gourab Bhattacharje
- Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur, West Midnapore, WB 721302, India
| | - Amit Ghosh
- School of Energy Science and Engineering, Indian Institute of Technology Kharagpur, Kharagpur, West Midnapore, WB 721302, India
| | - Amit Kumar Das
- Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur, West Midnapore, WB 721302, India
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5
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Sparks IL, Kado T, Prithviraj M, Nijjer J, Yan J, Morita YS. Lipoarabinomannan mediates localized cell wall integrity during division in mycobacteria. Nat Commun 2024; 15:2191. [PMID: 38467648 PMCID: PMC10928101 DOI: 10.1038/s41467-024-46565-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Accepted: 02/29/2024] [Indexed: 03/13/2024] Open
Abstract
The growth and division of mycobacteria, which include clinically relevant pathogens, deviate from that of canonical bacterial models. Despite their Gram-positive ancestry, mycobacteria synthesize and elongate a diderm envelope asymmetrically from the poles, with the old pole elongating more robustly than the new pole. The phosphatidylinositol-anchored lipoglycans lipomannan (LM) and lipoarabinomannan (LAM) are cell envelope components critical for host-pathogen interactions, but their physiological functions in mycobacteria remained elusive. In this work, using biosynthetic mutants of these lipoglycans, we examine their roles in maintaining cell envelope integrity in Mycobacterium smegmatis and Mycobacterium tuberculosis. We find that mutants defective in producing mature LAM fail to maintain rod cell shape specifically at the new pole and para-septal regions whereas a mutant that produces a larger LAM becomes multi-septated. Therefore, LAM plays critical and distinct roles at subcellular locations associated with division in mycobacteria, including maintenance of local cell wall integrity and septal placement.
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Affiliation(s)
- Ian L Sparks
- Department of Microbiology, University of Massachusetts, Amherst, MA, USA
| | - Takehiro Kado
- Department of Microbiology, University of Massachusetts, Amherst, MA, USA
| | | | - Japinder Nijjer
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA
- Quantitative Biology Institute, Yale University, New Haven, CT, USA
| | - Jing Yan
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA
- Quantitative Biology Institute, Yale University, New Haven, CT, USA
| | - Yasu S Morita
- Department of Microbiology, University of Massachusetts, Amherst, MA, USA.
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6
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Franklin A, Layton AJ, Mize T, Salgueiro VC, Sullivan R, Benedict ST, Gurcha SS, Anso I, Besra GS, Banzhaf M, Lovering AL, Williams SJ, Guerin ME, Scott NE, Prados-Rosales R, Lowe EC, Moynihan PJ. The mycobacterial glycoside hydrolase LamH enables capsular arabinomannan release and stimulates growth. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.26.563968. [PMID: 37961452 PMCID: PMC10634837 DOI: 10.1101/2023.10.26.563968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Mycobacterial glycolipids are important cell envelope structures that drive host-pathogen interactions. Arguably, the most important amongst these are lipoarabinomannan (LAM) and its precursor, lipomannan (LM), which are both trafficked out of the bacterium to the host via unknown mechanisms. An important class of exported LM/LAM is the capsular derivative of these molecules which is devoid of its lipid anchor. Here, we describe the identification of a glycoside hydrolase family 76 enzyme that we term LamH which specifically cleaves α-1,6-mannoside linkages within LM and LAM, driving its export to the capsule releasing its phosphatidyl-myo-inositol mannoside lipid anchor. Unexpectedly, we found that the catalytic activity of this enzyme is important for efficient exit from stationary phase cultures where arabinomannan acts as a signal for growth phase transition. Finally, we demonstrate that LamH is important for Mycobacterium tuberculosis survival in macrophages. These data provide a new framework for understanding the biological role of LAM in mycobacteria.
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Affiliation(s)
- Aaron Franklin
- School of Biosciences, University of Birmingham, Birmingham, U.K., B15 2TT
| | - Abigail J. Layton
- School of Biosciences, University of Birmingham, Birmingham, U.K., B15 2TT
| | - Todd Mize
- School of Biosciences, University of Birmingham, Birmingham, U.K., B15 2TT
| | - Vivian C. Salgueiro
- Department of Preventive Medicine, Public Health and Microbiology. School of Medicine. Universidad Autonoma de Madrid, 28029 Madrid, Spain
| | - Rudi Sullivan
- School of Biosciences, University of Birmingham, Birmingham, U.K., B15 2TT
| | - Samuel T. Benedict
- School of Biosciences, University of Birmingham, Birmingham, U.K., B15 2TT
| | - Sudagar S. Gurcha
- School of Biosciences, University of Birmingham, Birmingham, U.K., B15 2TT
| | - Itxaso Anso
- Structural Glycobiology Laboratory, Biocruces Health Research Institute, Barakaldo, Bizkaia, 48903, Spain
| | - Gurdyal S. Besra
- School of Biosciences, University of Birmingham, Birmingham, U.K., B15 2TT
| | - Manuel Banzhaf
- School of Biosciences, University of Birmingham, Birmingham, U.K., B15 2TT
| | - Andrew L. Lovering
- School of Biosciences, University of Birmingham, Birmingham, U.K., B15 2TT
| | - Spencer J. Williams
- School of Chemistry and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Marcelo E. Guerin
- Structural Glycobiology Laboratory, Department of Structural and Molecular Biology; Molecular Biology Institute of Barcelona (IBMB), Spanish National Research Council (CSIC), Barcelona Science Park, c/Baldiri Reixac 4-8, Tower R, 08028 Barcelona, Catalonia, Spain
| | - Nichollas E. Scott
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne 3000, Australia
| | - Rafael Prados-Rosales
- Department of Preventive Medicine, Public Health and Microbiology. School of Medicine. Universidad Autonoma de Madrid, 28029 Madrid, Spain
| | - Elisabeth C. Lowe
- Newcastle University Biosciences Institute, Medical School, Newcastle University, Newcastle upon Tyne, U.K., NE2 4HH
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7
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Sparks IL, Nijjer J, Yan J, Morita YS. Lipoarabinomannan regulates septation in Mycobacterium smegmatis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.26.534150. [PMID: 36993273 PMCID: PMC10055410 DOI: 10.1101/2023.03.26.534150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
The growth and division of mycobacteria, which include several clinically relevant pathogens, deviate significantly from that of canonical bacterial models. Despite their Gram-positive ancestry, mycobacteria synthesize and elongate a diderm envelope asymmetrically from the poles, with the old pole elongating more robustly than the new pole. In addition to being structurally distinct, the molecular components of the mycobacterial envelope are also evolutionarily unique, including the phosphatidylinositol-anchored lipoglycans lipomannan (LM) and lipoarabinomannan (LAM). LM and LAM modulate host immunity during infection, but their role outside of intracellular survival remains poorly understood, despite their widespread conservation among non-pathogenic and opportunistically pathogenic mycobacteria. Previously, Mycobacterium smegmatis and Mycobacterium tuberculosis mutants producing structurally altered LM and LAM were shown to grow slowly under certain conditions and to be more sensitive to antibiotics, suggesting that mycobacterial lipoglycans may support cellular integrity or growth. To test this, we constructed multiple biosynthetic lipoglycan mutants of M. smegmatis and determined the effect of each mutation on cell wall biosynthesis, envelope integrity, and division. We found that mutants deficient in LAM, but not LM, fail to maintain cell wall integrity in a medium-dependent manner, with envelope deformations specifically associated with septa and new poles. Conversely, a mutant producing abnormally large LAM formed multiseptated cells in way distinct from that observed in a septal hydrolase mutant. These results show that LAM plays critical and distinct roles at subcellular locations associated with division in mycobacteria, including maintenance of local cell envelope integrity and septal placement.
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Affiliation(s)
- Ian L. Sparks
- Department of Microbiology, University of Massachusetts, Amherst, MA, USA
| | - Japinder Nijjer
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven CT, USA
- Quantitative Biology Institute, Yale University, New Haven, CT, USA
| | - Jing Yan
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven CT, USA
- Quantitative Biology Institute, Yale University, New Haven, CT, USA
| | - Yasu S. Morita
- Department of Microbiology, University of Massachusetts, Amherst, MA, USA
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8
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Hodges H, Obeng K, Avanzi C, Ausmus AP, Angala SK, Kalera K, Palcekova Z, Swarts BM, Jackson M. Azido Inositol Probes Enable Metabolic Labeling of Inositol-Containing Glycans and Reveal an Inositol Importer in Mycobacteria. ACS Chem Biol 2023; 18:595-604. [PMID: 36856664 PMCID: PMC10071489 DOI: 10.1021/acschembio.2c00912] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2023]
Abstract
Bacteria from the genus Mycobacterium include pathogens that cause serious diseases in humans and remain as difficult infectious agents to treat. Central to these challenges are the composition and organization of the mycobacterial cell envelope, which includes unique and complex glycans. Inositol is an essential metabolite for mycobacteria due to its presence in the structural core of the immunomodulatory cell envelope glycolipids phosphatidylinositol mannoside (PIM) and PIM-anchored lipomannan (LM) and lipoarabinomannan (LAM). Despite their importance to mycobacterial physiology and pathogenesis, many aspects of PIM, LM, and LAM construction and dynamics remain poorly understood. Recently, probes that allow metabolic labeling and detection of specific mycobacterial glycans have been developed to investigate cell envelope assembly and dynamics. However, these tools have been limited to peptidoglycan, arabinogalactan, and mycolic acid-containing glycolipids. Herein, we report the development of synthetic azido inositol (InoAz) analogues as probes that can metabolically label PIMs, LM, and LAM in intact mycobacteria. Additionally, we leverage an InoAz probe to discover an inositol importer and catabolic pathway in Mycobacterium smegmatis. We anticipate that in the future, InoAz probes, in combination with bioorthogonal chemistry, will provide a valuable tool for investigating PIM, LM, and LAM biosynthesis, transport, and dynamics in diverse mycobacterial organisms.
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Affiliation(s)
- Heather Hodges
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, 80523 USA
| | - Kwaku Obeng
- Department of Chemistry and Biochemistry, Central Michigan University, Mount Pleasant, MI, 48859 USA
| | - Charlotte Avanzi
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, 80523 USA
| | - Alex P. Ausmus
- Department of Chemistry and Biochemistry, Central Michigan University, Mount Pleasant, MI, 48859 USA
| | - Shiva Kumar Angala
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, 80523 USA
| | - Karishma Kalera
- Department of Chemistry and Biochemistry, Central Michigan University, Mount Pleasant, MI, 48859 USA
- Biochemistry, Cellular, and Molecular Biology Program, Central Michigan University, Mount Pleasant, MI, 48859 USA
| | - Zuzana Palcekova
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, 80523 USA
| | - Benjamin M. Swarts
- Department of Chemistry and Biochemistry, Central Michigan University, Mount Pleasant, MI, 48859 USA
- Biochemistry, Cellular, and Molecular Biology Program, Central Michigan University, Mount Pleasant, MI, 48859 USA
| | - Mary Jackson
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, 80523 USA
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9
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Nguyen PP, Kado T, Prithviraj M, Siegrist MS, Morita YS. Inositol acylation of phosphatidylinositol mannosides: a rapid mass response to membrane fluidization in mycobacteria. J Lipid Res 2022; 63:100262. [PMID: 35952902 PMCID: PMC9490103 DOI: 10.1016/j.jlr.2022.100262] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2022] [Revised: 07/25/2022] [Accepted: 07/29/2022] [Indexed: 11/16/2022] Open
Abstract
Mycobacteria share an unusually complex, multilayered cell envelope, which contributes to adaptation to changing environments. The plasma membrane is the deepest layer of the cell envelope and acts as the final permeability barrier against outside molecules. There is an obvious need to maintain the plasma membrane integrity, but the adaptive responses of the plasma membrane to stress exposure remain poorly understood. Using chemical treatment and heat stress to fluidize the membrane, we show here that phosphatidylinositol (PI)-anchored plasma membrane glycolipids known as PI mannosides (PIMs) are rapidly remodeled upon membrane fluidization in Mycobacterium smegmatis. Without membrane stress, PIMs are predominantly in a triacylated form: two acyl chains of the PI moiety plus one acyl chain modified at one of the mannose residues. Upon membrane fluidization, we determined the fourth fatty acid is added to the inositol moiety of PIMs, making them tetra-acylated variants. Additionally, we show that PIM inositol acylation is a rapid response independent of de novo protein synthesis, representing one of the fastest mass conversions of lipid molecules found in nature. Strikingly, we found that M. smegmatis is more resistant to the bactericidal effect of a cationic detergent after benzyl alcohol pre-exposure. We further demonstrate that fluidization-induced PIM inositol acylation is conserved in pathogens such as Mycobacterium tuberculosis and Mycobacterium abscessus. Our results demonstrate that mycobacteria possess a mechanism to sense plasma membrane fluidity change. We suggest that inositol acylation of PIMs is a novel membrane stress response that enables mycobacterial cells to resist membrane fluidization.
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Affiliation(s)
- Peter P Nguyen
- Department of Microbiology, University of Massachusetts, Amherst, MA, USA
| | - Takehiro Kado
- Department of Microbiology, University of Massachusetts, Amherst, MA, USA
| | | | - M Sloan Siegrist
- Department of Microbiology, University of Massachusetts, Amherst, MA, USA; Molecular and Cellular Biology Graduate Program, University of Massachusetts, Amherst, MA, USA
| | - Yasu S Morita
- Department of Microbiology, University of Massachusetts, Amherst, MA, USA; Molecular and Cellular Biology Graduate Program, University of Massachusetts, Amherst, MA, USA.
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10
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Quantitative detection of mycobacterial mannophosphoinositides in tuberculosis patients by real-time immuno-PCR assay. METHODS IN MICROBIOLOGY 2022; 201:106563. [DOI: 10.1016/j.mimet.2022.106563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2022] [Revised: 08/26/2022] [Accepted: 08/28/2022] [Indexed: 11/22/2022]
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11
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Bhattacharje G, Ghosh A, Das AK. In-silico identification of critical residues in the mannose-transfer mechanism of phosphatidyl-myo-inositol mannosyltransferase B′. Biochem Biophys Res Commun 2022; 621:14-19. [DOI: 10.1016/j.bbrc.2022.06.087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Accepted: 06/26/2022] [Indexed: 11/02/2022]
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12
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Bhattacharje G, Ghosh A, Das AK. Understanding the Mannose Transfer Mechanism of Mycobacterial Phosphatidyl-myo-inositol Mannosyltransferase A from Molecular Dynamics Simulations. ACS OMEGA 2022; 7:19288-19304. [PMID: 35721920 PMCID: PMC9202250 DOI: 10.1021/acsomega.2c00832] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Accepted: 05/20/2022] [Indexed: 06/15/2023]
Abstract
Glycolipids like phosphatidylinositol hexamannosides (PIM6) and lipoglycans, such as lipomannan (LM) and lipoarabinomannan (LAM), play crucial roles in virulence, survival, and antibiotic resistance of various mycobacterial species. Phosphatidyl-myo-inositol mannosyltransferase A (PimA) catalyzes the transfer of the mannose moiety (M) from GDP-mannose (GDPM) to phosphatidyl-myo-inositol (PI) to synthesize GDP and phosphatidyl-myo-inositol monomannoside (PIM). This PIM is mannosylated, acylated, and further modified to give rise to the higher PIMs, LM, and LAM. It is yet to be known how PI, PIM, PI-GDPM, and PIM-GDP interact with PimA. Here, we report the docked structures of PI and PIM to understand how the substrates and the products interact with PimA. Using molecular dynamics (MD) simulations for 300 ns, we have investigated how various ligand-bound conformations change the dynamics of PimA. Our studies demonstrated the "open to closed" motions of PimA. We observed that PimA is least dynamic when bound to both GDPM and PI. MD simulations indicated that the loop residues 59-70 and the α-helical residues 73-86 of PimA play important roles while interacting with both PI and PIM. MD analyses also suggested that the residues Y9, P59, R68, L69, N97, R196, R201, K202, and R228 of PimA play significant roles in the mannose transfer reaction. Overall, docking studies and MD simulations provide crucial insights to design future therapeutic drugs against mycobacterial PimA.
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Affiliation(s)
- Gourab Bhattacharje
- Department
of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
| | - Amit Ghosh
- School
of Energy Science and Engineering, Indian
Institute of Technology Kharagpur, Kharagpur 721302, India
- P.K.
Sinha Centre for Bioenergy and Renewables, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
| | - Amit Kumar Das
- Department
of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
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13
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Nobre RN, Esteves AM, Borges N, Rebelo S, Liu Y, Mancia F, Santos H. Production and Purification of Phosphatidylinositol Mannosides from Mycobacterium smegmatis Biomass. Curr Protoc 2022; 2:e458. [PMID: 35758621 PMCID: PMC9245178 DOI: 10.1002/cpz1.458] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Mycobacterium tuberculosis, the etiological agent of tuberculosis, is regarded as the most successful pathogen of humankind and a major threat to global health. The mycobacterial cell wall is vital for cell growth, virulence, and resistance to antibiotics, and thus constitutes a unique target for drug development. To characterize the enzymes catalyzing the synthesis of the cell wall components, considerable amounts of substrates are required. Since many mycobacterial cell wall lipids, particularly phosphatidylinositol mannosides (PIMs), are not commercially available, isolation from cell biomass is the most straightforward way to obtain these compounds. In this study, we optimized a protocol to extract and purify PIM species, in particular Ac1 PIM2 and Ac1 PIM4 , which can be further used for the identification and characterization of target enzymes. PIMs were extracted from Mycobacterium smegmatis mc2 155 ΔPimE using organic solvents, and purified through three consecutive chromatography steps. Thin-layer chromatography (TLC) was used in-between purification steps to evaluate the success of lipid separation, and nuclear magnetic resonance (NMR) was used for product quantification and to assess purity. Typically, from a 60 g batch of M. smegmatis biomass we were able to isolate approximately 9 mg of Ac1 PIM2 and 1.8 mg of Ac1 PIM4 . This is the first time the purification of phosphatidylinositol tetramannoside has been reported. © 2022 Wiley Periodicals LLC. Basic Protocol 1: Growth of M. smegmatis mc2 155 ∆PimE Basic Protocol 2: Extraction of lipids from M. smegmatis mc2 155 ∆PimE Basic Protocol 3: Treatment of the lipid extract for isolation of phospholipids Basic Protocol 4: Isolation of phosphatidylinositol mannosides Basic Protocol 5: Quantification of phosphatidylinositol mannosides.
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Affiliation(s)
- Rodrigo N. Nobre
- Instituto de Tecnologia Química e Biológica António Xavier, ITQB NOVA, Universidade Nova de Lisboa, Av. da República – EAN, Apartado 127, 2780-157 Oeiras, Portugal
| | - Ana M. Esteves
- Instituto de Tecnologia Química e Biológica António Xavier, ITQB NOVA, Universidade Nova de Lisboa, Av. da República – EAN, Apartado 127, 2780-157 Oeiras, Portugal
| | - Nuno Borges
- Instituto de Tecnologia Química e Biológica António Xavier, ITQB NOVA, Universidade Nova de Lisboa, Av. da República – EAN, Apartado 127, 2780-157 Oeiras, Portugal
| | - Sara Rebelo
- Instituto de Tecnologia Química e Biológica António Xavier, ITQB NOVA, Universidade Nova de Lisboa, Av. da República – EAN, Apartado 127, 2780-157 Oeiras, Portugal
| | - Yaqi Liu
- Columbia University Irving Medical Center, 1150 St. Nicholas Avenue, Russ Berrie pavilion, room 520B, New York, NY 10032, USA
| | - Filippo Mancia
- Columbia University Irving Medical Center, 1150 St. Nicholas Avenue, Russ Berrie pavilion, room 520B, New York, NY 10032, USA
| | - Helena Santos
- Instituto de Tecnologia Química e Biológica António Xavier, ITQB NOVA, Universidade Nova de Lisboa, Av. da República – EAN, Apartado 127, 2780-157 Oeiras, Portugal
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14
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Patel O, Brammananth R, Dai W, Panjikar S, Coppel RL, Lucet IS, Crellin PK. Crystal structure of the putative cell-wall lipoglycan biosynthesis protein LmcA from Mycobacterium smegmatis. Acta Crystallogr D Struct Biol 2022; 78:494-508. [PMID: 35362472 PMCID: PMC8972800 DOI: 10.1107/s2059798322001772] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Accepted: 02/16/2022] [Indexed: 11/17/2022] Open
Abstract
The bacterial genus Mycobacterium includes important pathogens, most notably M. tuberculosis, which infects one-quarter of the entire human population, resulting in around 1.4 million deaths from tuberculosis each year. Mycobacteria, and the closely related corynebacteria, synthesize a class of abundant glycolipids, the phosphatidyl-myo-inositol mannosides (PIMs). PIMs serve as membrane anchors for hyperglycosylated species, lipomannan (LM) and lipoarabinomannan (LAM), which are surface-exposed and modulate the host immune response. Previously, in studies using the model species Corynebacterium glutamicum, NCgl2760 was identified as a novel membrane protein that is required for the synthesis of full-length LM and LAM. Here, the first crystal structure of its ortholog in Mycobacterium smegmatis, MSMEG_0317, is reported at 1.8 Å resolution. The structure revealed an elongated β-barrel fold enclosing two distinct cavities and one α-helix extending away from the β-barrel core, resembling a `cone with a flake' arrangement. Through xenon derivatization and structural comparison with AlphaFold2-derived predictions of the M. tuberculosis homolog Rv0227c, structural elements were identified that may undergo conformational changes to switch from `closed' to `open' conformations, allowing cavity access. An AlphaFold2-derived NCgl2760 model predicted a smaller β-barrel core with an enclosed central cavity, suggesting that all three proteins, which were collectively termed LmcA, may have a common mechanism of ligand binding through these cavities. These findings provide new structural insights into the biosynthetic pathway for a family of surface lipoglycans with important roles in mycobacterial pathogenesis.
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Affiliation(s)
- Onisha Patel
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia
| | - Rajini Brammananth
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Victoria 3800, Australia
| | - Weiwen Dai
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia
| | - Santosh Panjikar
- Australian Synchrotron, Clayton, Victoria 3168, Australia
- Department of Molecular Biology and Biochemistry, Monash University, Victoria 3800, Australia
| | - Ross L. Coppel
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Victoria 3800, Australia
| | - Isabelle S. Lucet
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia
| | - Paul K. Crellin
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Victoria 3800, Australia
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15
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Anso I, Basso LGM, Wang L, Marina A, Páez-Pérez ED, Jäger C, Gavotto F, Tersa M, Perrone S, Contreras FX, Prandi J, Gilleron M, Linster CL, Corzana F, Lowary TL, Trastoy B, Guerin ME. Molecular ruler mechanism and interfacial catalysis of the integral membrane acyltransferase PatA. SCIENCE ADVANCES 2021; 7:eabj4565. [PMID: 34652941 PMCID: PMC8519569 DOI: 10.1126/sciadv.abj4565] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 08/24/2021] [Indexed: 05/28/2023]
Abstract
Glycolipids are prominent components of bacterial membranes that play critical roles not only in maintaining the structural integrity of the cell but also in modulating host-pathogen interactions. PatA is an essential acyltransferase involved in the biosynthesis of phosphatidyl-myo-inositol mannosides (PIMs), key structural elements and virulence factors of Mycobacterium tuberculosis. We demonstrate by electron spin resonance spectroscopy and surface plasmon resonance that PatA is an integral membrane acyltransferase tightly anchored to anionic lipid bilayers, using a two-helix structural motif and electrostatic interactions. PatA dictates the acyl chain composition of the glycolipid by using an acyl chain selectivity “ruler.” We established this by a combination of structural biology, enzymatic activity, and binding measurements on chemically synthesized nonhydrolyzable acyl–coenzyme A (CoA) derivatives. We propose an interfacial catalytic mechanism that allows PatA to acylate hydrophobic PIMs anchored in the inner membrane of mycobacteria, through the use of water-soluble acyl-CoA donors.
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Affiliation(s)
- Itxaso Anso
- Structural Glycobiology Laboratory, Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Technology Park, Building 801A, 48160 Derio, Spain
- Structural Glycobiology Laboratory, Biocruces Bizkaia Health Research Institute, Cruces University Hospital, 48903 Barakaldo, Bizkaia, Spain
| | - Luis G. M. Basso
- Laboratório de Ciências Físicas, Centro de Ciência e Tecnologia, Universidade Estadual do Norte Fluminense Darcy Ribeiro, Avenida Alberto Lamego, 2000, Campos dos Goytacazes, 28013-602 Rio de Janeiro, Brazil
- Laboratório de Biofísica Molecular, Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Avenida Bandeirantes, 3900, 14040-901 Ribeirão Preto, São Paulo, Brazil
| | - Lei Wang
- Department of Chemistry, University of Alberta, Edmonton, Alberta, T6G 2G2, Canada
| | - Alberto Marina
- Structural Glycobiology Laboratory, Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Technology Park, Building 801A, 48160 Derio, Spain
| | - Edgar D. Páez-Pérez
- Structural Glycobiology Laboratory, Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Technology Park, Building 801A, 48160 Derio, Spain
- IPICYT, División de Biología Molecular, Instituto Potosino de Investigación Científica y Tecnológica A.C., San Luis Potosí, México
| | - Christian Jäger
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, L-4367 Belvaux, Luxembourg
| | - Floriane Gavotto
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, L-4367 Belvaux, Luxembourg
| | - Montse Tersa
- Structural Glycobiology Laboratory, Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Technology Park, Building 801A, 48160 Derio, Spain
| | - Sebastián Perrone
- Structural Glycobiology Laboratory, Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Technology Park, Building 801A, 48160 Derio, Spain
- Structural Glycobiology Laboratory, Biocruces Bizkaia Health Research Institute, Cruces University Hospital, 48903 Barakaldo, Bizkaia, Spain
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, L-4367 Belvaux, Luxembourg
| | - F.-Xabier Contreras
- Instituto Biofisika, Consejo Superior de Investigaciones Científicas, Universidad del País Vasco/Euskal Herriko Unibertsitatea (CSIC,UPV/EHU), Barrio Sarriena s/n, Leioa, 48940 Bizkaia, Spain
- Departamento de Bioquímica, Universidad del País Vasco, Leioa, 48940 Bizkaia, Spain
- IKERBASQUE, Basque Foundation for Science, 48013 Bilbao, Spain
| | - Jacques Prandi
- Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, UPS, 205 route de Narbonne, F-31077 Toulouse, France
| | - Martine Gilleron
- Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, UPS, 205 route de Narbonne, F-31077 Toulouse, France
| | - Carole L. Linster
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, L-4367 Belvaux, Luxembourg
| | - Francisco Corzana
- Departamento Química and Centro de Investigación en Síntesis Química, Universidad de La Rioja, 26006 Rioja, Spain
| | - Todd L. Lowary
- Department of Chemistry, University of Alberta, Edmonton, Alberta, T6G 2G2, Canada
- Institute of Biological Chemistry, Academia Sinica, Academia Road, Section 2, #128, Nangang, Taipei 11529, Taiwan
- Institute of Biochemical Sciences, National Taiwan University, Section 4, #1, Roosevelt Road, Taipei 10617, Taiwan
| | - Beatriz Trastoy
- Structural Glycobiology Laboratory, Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Technology Park, Building 801A, 48160 Derio, Spain
- Structural Glycobiology Laboratory, Biocruces Bizkaia Health Research Institute, Cruces University Hospital, 48903 Barakaldo, Bizkaia, Spain
| | - Marcelo E. Guerin
- Structural Glycobiology Laboratory, Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Technology Park, Building 801A, 48160 Derio, Spain
- Structural Glycobiology Laboratory, Biocruces Bizkaia Health Research Institute, Cruces University Hospital, 48903 Barakaldo, Bizkaia, Spain
- IKERBASQUE, Basque Foundation for Science, 48013 Bilbao, Spain
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16
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Labarre C, Dautin N, Grzegorzewicz A, Jackson M, McNeil M, Mohiman N, Sago L, Bayan N. S 16 and T 18 mannosylation sites of LppX are not essential for its activity in phthiocerol dimycocerosates localization at the surface of Mycobacterium tuberculosis. Res Microbiol 2021; 172:103874. [PMID: 34492336 DOI: 10.1016/j.resmic.2021.103874] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 07/12/2021] [Accepted: 08/02/2021] [Indexed: 11/28/2022]
Abstract
LppX is an important virulence factor essential for surface localization of phthiocerol dimycocerosates (DIM) in Mycobacterium tuberculosis. Based on Concanavalin A recognition, M. tuberculosis LppX (LppX-tb) was initially proposed to be glycosylated in M. tuberculosis and more recently this glycosylation was characterized by mass spectrometry analysis on LppX-tb expressed and purified from Corynebacterium glutamicum. Here, using this model organism and Mycobacterium smegmatis, we show that S16 and T18 residues of LppX-tb are indeed glycosylated with several hexoses units. Interestingly this glycosylation is strictly dependent on the mannosyl transferase PMT which, in M. tuberculosis, has been reported to be crucial for virulence. Using a site directed mutagenesis approach, we were able to show that the absence of S16 and T18 glycosylation does not alter phthiocerol dimycocerosates (DIM) localization in M. tuberculosis.
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Affiliation(s)
- Cécile Labarre
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198, Gif-sur-Yvette cedex, France.
| | - Nathalie Dautin
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198, Gif-sur-Yvette cedex, France; Present address: Laboratoire de Biologie Physico-Chimique des Protéines Membranaires, Université de Paris, LBPC-PM, CNRS, UMR7099, 75005, Paris, France.
| | - Anna Grzegorzewicz
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Colorado, Fort Collins, USA.
| | - Mary Jackson
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Colorado, Fort Collins, USA.
| | - Michael McNeil
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Colorado, Fort Collins, USA.
| | - Niloofar Mohiman
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198, Gif-sur-Yvette cedex, France.
| | - Laila Sago
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198, Gif-sur-Yvette cedex, France.
| | - Nicolas Bayan
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198, Gif-sur-Yvette cedex, France.
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17
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Jackson M, Stevens CM, Zhang L, Zgurskaya HI, Niederweis M. Transporters Involved in the Biogenesis and Functionalization of the Mycobacterial Cell Envelope. Chem Rev 2021; 121:5124-5157. [PMID: 33170669 PMCID: PMC8107195 DOI: 10.1021/acs.chemrev.0c00869] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The biology of mycobacteria is dominated by a complex cell envelope of unique composition and structure and of exceptionally low permeability. This cell envelope is the basis of many of the pathogenic features of mycobacteria and the site of susceptibility and resistance to many antibiotics and host defense mechanisms. This review is focused on the transporters that assemble and functionalize this complex structure. It highlights both the progress and the limits of our understanding of how (lipo)polysaccharides, (glyco)lipids, and other bacterial secretion products are translocated across the different layers of the cell envelope to their final extra-cytoplasmic location. It further describes some of the unique strategies evolved by mycobacteria to import nutrients and other products through this highly impermeable barrier.
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Affiliation(s)
- Mary Jackson
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523-1682, USA
| | - Casey M. Stevens
- University of Oklahoma, Department of Chemistry and Biochemistry, 101 Stephenson Parkway, Norman, OK 73019, USA
| | - Lei Zhang
- Department of Microbiology, University of Alabama at Birmingham, 845 19th Street South, Birmingham, AL 35294, USA
| | - Helen I. Zgurskaya
- University of Oklahoma, Department of Chemistry and Biochemistry, 101 Stephenson Parkway, Norman, OK 73019, USA
| | - Michael Niederweis
- Department of Microbiology, University of Alabama at Birmingham, 845 19th Street South, Birmingham, AL 35294, USA
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18
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Flores J, Cancino JC, Chavez-Galan L. Lipoarabinomannan as a Point-of-Care Assay for Diagnosis of Tuberculosis: How Far Are We to Use It? Front Microbiol 2021; 12:638047. [PMID: 33935997 PMCID: PMC8081860 DOI: 10.3389/fmicb.2021.638047] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 03/22/2021] [Indexed: 12/13/2022] Open
Abstract
Tuberculosis (TB) is still a severe public health problem; the current diagnostic tests have limitations that delay treatment onset. Lipoarabinomannan (LAM) is a glycolipid that is a component of the cell wall of the bacillus Mycobacterium tuberculosis, the etiologic agent of TB. This glycolipid is excreted as a soluble form in urine. The World Health Organization has established that the design of new TB diagnostic methods is one of the priorities within the EndTB Strategy. LAM has been suggested as a biomarker to develop diagnostic tests based on its identification in urine, and it is one of the most prominent candidates to develop point-of-care diagnostic test because urine samples can be easily collected. Moreover, LAM can regulate the immune response in the host and can be found in the serum of TB patients, where it probably affects a wide variety of host cell populations, consequently influencing the quality of both innate and adaptive immune responses during TB infection. Here, we revised the evidence that supports that LAM could be used as a tool for the development of new point-of-care tests for TB diagnosis, and we discussed the mechanisms that could contribute to the low sensitivity of diagnostic testing.
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Affiliation(s)
- Julio Flores
- Laboratory of Integrative Immunology, Instituto Nacional de Enfermedades Respiratorias Ismael Cosio Villegas, Mexico City, Mexico.,Laboratory of Immunomicrobiology, Department of Microbiology, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City, Mexico
| | - Juan Carlos Cancino
- Laboratory of Immunomicrobiology, Department of Microbiology, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City, Mexico
| | - Leslie Chavez-Galan
- Laboratory of Integrative Immunology, Instituto Nacional de Enfermedades Respiratorias Ismael Cosio Villegas, Mexico City, Mexico
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19
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The Phosphatidyl- myo-Inositol Dimannoside Acyltransferase PatA Is Essential for Mycobacterium tuberculosis Growth In Vitro and In Vivo. J Bacteriol 2021; 203:JB.00439-20. [PMID: 33468587 DOI: 10.1128/jb.00439-20] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 12/30/2020] [Indexed: 01/20/2023] Open
Abstract
Mycobacterium tuberculosis comprises an unusual cell envelope dominated by unique lipids and glycans that provides a permeability barrier against hydrophilic drugs and is central for its survival and virulence. Phosphatidyl-myo-inositol mannosides (PIMs) are glycolipids considered to be not only key structural components of the cell envelope but also the precursors of lipomannan (LM) and lipoarabinomannan (LAM), important lipoglycans implicated in host-pathogen interactions. Here, we focus on PatA, a membrane-associated acyltransferase that transfers a palmitoyl moiety from palmitoyl coenzyme A (palmitoyl-CoA) to the 6-position of the mannose ring linked to the 2-position of inositol in PIM1/PIM2 We validate that the function of PatA is vital for M. tuberculosis in vitro and in vivo We constructed a patA conditional mutant and showed that silencing patA is bactericidal in batch cultures. This phenotype was associated with significantly reduced levels of Ac1PIM2, an important structural component of the mycobacterial inner membrane. The requirement of PatA for viability was also demonstrated during macrophage infection and in a mouse model of infection, where a dramatic decrease in viable counts was observed upon silencing of the patA gene. This is reminiscent of the behavior of PimA, the mannosyltransferase that initiates the PIM pathway, also found to be essential for M. tuberculosis growth in vitro and in vivo Altogether, the experimental data highlight the significance of the early steps of the PIM biosynthetic pathway for M. tuberculosis physiology and reveal that PatA is a novel target for drug discovery programs against this major human pathogen.IMPORTANCE Tuberculosis (TB) is the leading cause of death from a single infectious agent. The emergence of drug resistance in strains of M. tuberculosis, the etiologic agent of TB, emphasizes the need to identify new targets and antimicrobial agents. The mycobacterial cell envelope is a major factor in this intrinsic drug resistance. Here, we have focused on the biosynthesis of PIMs, key virulence factors and important components of the cell envelope. Specifically, we have determined that PatA, the acyltransferase responsible for the first acylation step of the PIM synthesis pathway, is essential in M. tuberculosis These results highlight the importance of early steps of the PIM biosynthetic pathway for mycobacterial physiology and the suitability of PatA as a potential new drug target.
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20
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The thick waxy coat of mycobacteria, a protective layer against antibiotics and the host's immune system. Biochem J 2020; 477:1983-2006. [PMID: 32470138 PMCID: PMC7261415 DOI: 10.1042/bcj20200194] [Citation(s) in RCA: 76] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 04/30/2020] [Accepted: 05/04/2020] [Indexed: 12/22/2022]
Abstract
Tuberculosis, caused by the pathogenic bacterium Mycobacterium tuberculosis (Mtb), is the leading cause of death from an infectious disease, with a mortality rate of over a million people per year. This pathogen's remarkable resilience and infectivity is largely due to its unique waxy cell envelope, 40% of which comprises complex lipids. Therefore, an understanding of the structure and function of the cell wall lipids is of huge indirect clinical significance. This review provides a synopsis of the cell envelope and the major lipids contained within, including structure, biosynthesis and roles in pathogenesis.
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21
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Batt SM, Burke CE, Moorey AR, Besra GS. Antibiotics and resistance: the two-sided coin of the mycobacterial cell wall. Cell Surf 2020; 6:100044. [PMID: 32995684 PMCID: PMC7502851 DOI: 10.1016/j.tcsw.2020.100044] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 08/26/2020] [Accepted: 08/26/2020] [Indexed: 01/07/2023] Open
Abstract
Mycobacterium tuberculosis, the bacterium responsible for tuberculosis, is the global leading cause of mortality from an infectious agent. Part of this success relies on the unique cell wall, which consists of a thick waxy coat with tightly packed layers of complexed sugars, lipids and peptides. This coat provides a protective hydrophobic barrier to antibiotics and the host's defences, while enabling the bacterium to spread efficiently through sputum to infect and survive within the macrophages of new hosts. However, part of this success comes at a cost, with many of the current first- and second-line drugs targeting the enzymes involved in cell wall biosynthesis. The flip side of this coin is that resistance to these drugs develops either in the target enzymes or the activation pathways of the drugs, paving the way for new resistant clinical strains. This review provides a synopsis of the structure and synthesis of the cell wall and the major current drugs and targets, along with any mechanisms of resistance.
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Affiliation(s)
- Sarah M. Batt
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Christopher E. Burke
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Alice R. Moorey
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Gurdyal S. Besra
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
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22
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Role of LmeA, a Mycobacterial Periplasmic Protein, in Maintaining the Mannosyltransferase MptA and Its Product Lipomannan under Stress. mSphere 2020; 5:5/6/e01039-20. [PMID: 33148829 PMCID: PMC7643837 DOI: 10.1128/msphere.01039-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Mycobacteria differentially regulate the cellular amounts of lipoglycans in response to environmental changes, but the molecular mechanisms of this regulation remain unknown. Here, we demonstrate that cellular lipoarabinomannan (LAM) levels rapidly decline under two stress conditions, stationary growth phase and nutrient starvation, while the levels of another related lipoglycan, lipomannan (LM), stay relatively constant. The persistence of LM under stress correlated with the maintenance of two key mannosyltransferases, MptA and MptC, in the LM biosynthetic pathway. We further showed that the stress exposures lead to the upregulation of lmeA gene expression and that the periplasmic protein LmeA plays a key role in maintaining the enzyme MptA and its product LM under stress conditions. These findings reveal new aspects of how lipoglycan biosynthesis is regulated under stress conditions in mycobacteria. The mycobacterial cell envelope has a diderm structure, composed of an outer mycomembrane, an arabinogalactan-peptidoglycan cell wall, a periplasm, and an inner membrane. Lipomannan (LM) and lipoarabinomannan (LAM) are structural and immunomodulatory components of this cell envelope. LM/LAM biosynthesis involves a number of mannosyltransferases and acyltransferases, and MptA is an α1,6-mannosyltransferase involved in the final extension of the mannan chain. Recently, we reported the periplasmic protein LmeA being involved in the maturation of the mannan backbone in Mycobacterium smegmatis. Here, we examined the role of LmeA under stress conditions. We found that lmeA transcription was upregulated under two stress conditions: stationary growth phase and nutrient starvation. Under both conditions, LAM was decreased, but LM was relatively stable, suggesting that maintaining the cellular level of LM under stress is important. Surprisingly, the protein levels of MptA were decreased in an lmeA deletion (ΔlmeA) mutant under both stress conditions. The transcript levels of mptA in the ΔlmeA mutant were similar to or even higher than those in the wild type, indicating that the decrease of MptA protein was a posttranscriptional event. The ΔlmeA mutant was unable to maintain the cellular level of LM under stress, consistent with the decrease in MptA. Even during active growth, overexpression of LmeA led the cells to produce more LM and become more resistant to several antibiotics. Altogether, our study reveals the roles of LmeA in the homeostasis of the MptA mannosyltransferase, particularly under stress conditions, ensuring the stable expression of LM and the maintenance of cell envelope integrity. IMPORTANCE Mycobacteria differentially regulate the cellular amounts of lipoglycans in response to environmental changes, but the molecular mechanisms of this regulation remain unknown. Here, we demonstrate that cellular lipoarabinomannan (LAM) levels rapidly decline under two stress conditions, stationary growth phase and nutrient starvation, while the levels of another related lipoglycan, lipomannan (LM), stay relatively constant. The persistence of LM under stress correlated with the maintenance of two key mannosyltransferases, MptA and MptC, in the LM biosynthetic pathway. We further showed that the stress exposures lead to the upregulation of lmeA gene expression and that the periplasmic protein LmeA plays a key role in maintaining the enzyme MptA and its product LM under stress conditions. These findings reveal new aspects of how lipoglycan biosynthesis is regulated under stress conditions in mycobacteria.
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23
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Li M, Gašparovič H, Weng X, Chen S, Korduláková J, Jessen-Trefzer C. The Two-Component Locus MSMEG_0244/0246 Together With MSMEG_0243 Affects Biofilm Assembly in M. smegmatis Correlating With Changes in Phosphatidylinositol Mannosides Acylation. Front Microbiol 2020; 11:570606. [PMID: 33013801 PMCID: PMC7516205 DOI: 10.3389/fmicb.2020.570606] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 08/24/2020] [Indexed: 12/30/2022] Open
Abstract
Ferric and ferrous iron is an essential transition metal for growth of many bacterial species including mycobacteria. The genomic region msmeg_0234 to msmeg_0252 from Mycobacterium smegmatis is putatively involved in iron/heme metabolism. We investigate the genes encoding the presumed two component system MSMEG_0244/MSMEG_0246, the neighboring gene msmeg_0243 and their involvement in this process. We show that purified MSMEG_0243 indeed is a heme binding protein. Deletion of msmeg_0243/msmeg_0244/msmeg_0246 in Mycobacterium smegmatis leads to a defect in biofilm formation and colony growth on solid agar, however, this phenotype is independent of the supplied iron source. Further, analysis of the corresponding mutant and its lipids reveals that changes in morphology and biofilm formation correlate with altered acylation patterns of phosphatidylinositol mannosides (PIMs). We provide the first evidence that msmeg_0244/msmeg_0246 work in concert in cellular lipid homeostasis, especially in the maintenance of PIMs, with the heme-binding protein MSMEG_0243 as potential partner.
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Affiliation(s)
- Miaomaio Li
- Department of Pharmaceutical Biology and Biotechnology, University of Freiburg, Freiburg, Germany
| | - Henrich Gašparovič
- Department of Biochemistry, Faculty of Natural Sciences, Comenius University in Bratislava, Bratislava, Slovakia
| | - Xing Weng
- Department of Pharmaceutical Biology and Biotechnology, University of Freiburg, Freiburg, Germany
| | - Si Chen
- Department of Pharmaceutical Biology and Biotechnology, University of Freiburg, Freiburg, Germany
| | - Jana Korduláková
- Department of Biochemistry, Faculty of Natural Sciences, Comenius University in Bratislava, Bratislava, Slovakia
| | - Claudia Jessen-Trefzer
- Department of Pharmaceutical Biology and Biotechnology, University of Freiburg, Freiburg, Germany
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24
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Rodrigo-Unzueta A, Ghirardello M, Urresti S, Delso I, Giganti D, Anso I, Trastoy B, Comino N, Tersa M, D'Angelo C, Cifuente JO, Marina A, Liebau J, Mäler L, Chenal A, Albesa-Jové D, Merino P, Guerin ME. Dissecting the Structural and Chemical Determinants of the "Open-to-Closed" Motion in the Mannosyltransferase PimA from Mycobacteria. Biochemistry 2020; 59:2934-2945. [PMID: 32786405 DOI: 10.1021/acs.biochem.0c00376] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The phosphatidyl-myo-inositol mannosyltransferase A (PimA) is an essential peripheral membrane glycosyltransferase that initiates the biosynthetic pathway of phosphatidyl-myo-inositol mannosides (PIMs), key structural elements and virulence factors of Mycobacterium tuberculosis. PimA undergoes functionally important conformational changes, including (i) α-helix-to-β-strand and β-strand-to-α-helix transitions and (ii) an "open-to-closed" motion between the two Rossmann-fold domains, a conformational change that is necessary to generate a catalytically competent active site. In previous work, we established that GDP-Man and GDP stabilize the enzyme and facilitate the switch to a more compact active state. To determine the structural contribution of the mannose ring in such an activation mechanism, we analyzed a series of chemical derivatives, including mannose phosphate (Man-P) and mannose pyrophosphate-ribose (Man-PP-RIB), and additional GDP derivatives, such as pyrophosphate ribose (PP-RIB) and GMP, by the combined use of X-ray crystallography, limited proteolysis, circular dichroism, isothermal titration calorimetry, and small angle X-ray scattering methods. Although the β-phosphate is present, we found that the mannose ring, covalently attached to neither phosphate (Man-P) nor PP-RIB (Man-PP-RIB), does promote the switch to the active compact form of the enzyme. Therefore, the nucleotide moiety of GDP-Man, and not the sugar ring, facilitates the "open-to-closed" motion, with the β-phosphate group providing the high-affinity binding to PimA. Altogether, the experimental data contribute to a better understanding of the structural determinants involved in the "open-to-closed" motion not only observed in PimA but also visualized and/or predicted in other glycosyltransfeases. In addition, the experimental data might prove to be useful for the discovery and/or development of PimA and/or glycosyltransferase inhibitors.
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Affiliation(s)
- Ane Rodrigo-Unzueta
- Instituto Biofisika, Centro Mixto Consejo Superior de Investigaciones Científicas-Universidad del País Vasco/Euskal Herriko Unibertsitatea (CSIC, UPV/EHU), Barrio Sarriena s/n, Leioa, Bizkaia 48940, Spain.,Departamento de Bioquímica, Universidad del País Vasco, Barrio Sarriena s/n, Leioa, Bizkaia 48940, Spain
| | - Mattia Ghirardello
- Department of Synthesis and Structure of Biomolecules, Institute of Chemical Synthesis and Homogeneous Catalysis (ISQCH), University of Zaragoza-CSIC, 50009 Zaragoza, Spain
| | - Saioa Urresti
- Instituto Biofisika, Centro Mixto Consejo Superior de Investigaciones Científicas-Universidad del País Vasco/Euskal Herriko Unibertsitatea (CSIC, UPV/EHU), Barrio Sarriena s/n, Leioa, Bizkaia 48940, Spain.,Departamento de Bioquímica, Universidad del País Vasco, Barrio Sarriena s/n, Leioa, Bizkaia 48940, Spain
| | - Ignacio Delso
- Department of Synthesis and Structure of Biomolecules, Institute of Chemical Synthesis and Homogeneous Catalysis (ISQCH), University of Zaragoza-CSIC, 50009 Zaragoza, Spain
| | - David Giganti
- Instituto Biofisika, Centro Mixto Consejo Superior de Investigaciones Científicas-Universidad del País Vasco/Euskal Herriko Unibertsitatea (CSIC, UPV/EHU), Barrio Sarriena s/n, Leioa, Bizkaia 48940, Spain.,Departamento de Bioquímica, Universidad del País Vasco, Barrio Sarriena s/n, Leioa, Bizkaia 48940, Spain.,Unité de Microbiologie Structurale (CNRS URA 2185), Institut Pasteur, 25 rue du Dr. Roux, 75724 Paris Cedex 15, France
| | - Itxaso Anso
- Structural Biology Unit, CIC bioGUNE, Bizkaia Technology Park, 48160 Derio, Spain
| | - Beatriz Trastoy
- Structural Biology Unit, CIC bioGUNE, Bizkaia Technology Park, 48160 Derio, Spain
| | - Natalia Comino
- Structural Biology Unit, CIC bioGUNE, Bizkaia Technology Park, 48160 Derio, Spain
| | - Montse Tersa
- Structural Biology Unit, CIC bioGUNE, Bizkaia Technology Park, 48160 Derio, Spain
| | - Cecilia D'Angelo
- Structural Biology Unit, CIC bioGUNE, Bizkaia Technology Park, 48160 Derio, Spain
| | - Javier O Cifuente
- Structural Biology Unit, CIC bioGUNE, Bizkaia Technology Park, 48160 Derio, Spain
| | - Alberto Marina
- Structural Biology Unit, CIC bioGUNE, Bizkaia Technology Park, 48160 Derio, Spain
| | - Jobst Liebau
- Department of Biochemistry and Biophysics, Stockholm University, 106 91 Stockholm, Sweden
| | - Lena Mäler
- Department of Biochemistry and Biophysics, Stockholm University, 106 91 Stockholm, Sweden.,Department of Chemistry, Umeå University, 901 87 Umeå, Sweden
| | - Alexandre Chenal
- Unité de Biochimie des Interactions Macromoléculaires (CNRS UMR 3528), Institut Pasteur, 25 rue du Dr. Roux, 75724 Paris Cedex 15, France
| | - David Albesa-Jové
- Instituto Biofisika, Centro Mixto Consejo Superior de Investigaciones Científicas-Universidad del País Vasco/Euskal Herriko Unibertsitatea (CSIC, UPV/EHU), Barrio Sarriena s/n, Leioa, Bizkaia 48940, Spain.,Departamento de Bioquímica, Universidad del País Vasco, Barrio Sarriena s/n, Leioa, Bizkaia 48940, Spain.,Structural Biology Unit, CIC bioGUNE, Bizkaia Technology Park, 48160 Derio, Spain.,IKERBASQUE, Basque Foundation for Science, 48013 Bilbao, Spain
| | - Pedro Merino
- Glycobiology Unit, Institute of Biocomputation and Physics of Complex Systems (BIFI), University of Zaragoza, Campus San Francisco, 50009 Zaragoza, Spain
| | - Marcelo E Guerin
- Instituto Biofisika, Centro Mixto Consejo Superior de Investigaciones Científicas-Universidad del País Vasco/Euskal Herriko Unibertsitatea (CSIC, UPV/EHU), Barrio Sarriena s/n, Leioa, Bizkaia 48940, Spain.,Departamento de Bioquímica, Universidad del País Vasco, Barrio Sarriena s/n, Leioa, Bizkaia 48940, Spain.,Structural Biology Unit, CIC bioGUNE, Bizkaia Technology Park, 48160 Derio, Spain.,IKERBASQUE, Basque Foundation for Science, 48013 Bilbao, Spain
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25
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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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26
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Liebau J, Tersa M, Trastoy B, Patrick J, Rodrigo-Unzueta A, Corzana F, Sparrman T, Guerin ME, Mäler L. Unveiling the activation dynamics of a fold-switch bacterial glycosyltransferase by 19F NMR. J Biol Chem 2020; 295:9868-9878. [PMID: 32434931 PMCID: PMC7380196 DOI: 10.1074/jbc.ra120.014162] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 05/19/2020] [Indexed: 11/06/2022] Open
Abstract
Fold-switch pathways remodel the secondary structure topology of proteins in response to the cellular environment. It is a major challenge to understand the dynamics of these folding processes. Here, we conducted an in-depth analysis of the α-helix–to–β-strand and β-strand–to–α-helix transitions and domain motions displayed by the essential mannosyltransferase PimA from mycobacteria. Using 19F NMR, we identified four functionally relevant states of PimA that coexist in dynamic equilibria on millisecond-to-second timescales in solution. We discovered that fold-switching is a slow process, on the order of seconds, whereas domain motions occur simultaneously but are substantially faster, on the order of milliseconds. Strikingly, the addition of substrate accelerated the fold-switching dynamics of PimA. We propose a model in which the fold-switching dynamics constitute a mechanism for PimA activation.
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Affiliation(s)
- Jobst Liebau
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Montse Tersa
- Structural Biology Unit, Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Technology Park, Derio, Spain
| | - Beatriz Trastoy
- Structural Biology Unit, Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Technology Park, Derio, Spain
| | - Joan Patrick
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Ane Rodrigo-Unzueta
- Departamento de Bioquímica and Instituto Biofisika, Consejo Superior de Investigaciones Científicas-Universidad del País Vasco/Euskal Herriko Unibertsitatea (CSIC, UPV/EHU), Bizkaia, Spain
| | - Francisco Corzana
- Departamento de Química, Centro de Investigación en Síntesis Química, Universidad de La Rioja, Logroño, Spain
| | | | - Marcelo E Guerin
- Structural Biology Unit, Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Technology Park, Derio, Spain .,Departamento de Bioquímica and Instituto Biofisika, Consejo Superior de Investigaciones Científicas-Universidad del País Vasco/Euskal Herriko Unibertsitatea (CSIC, UPV/EHU), Bizkaia, Spain.,IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
| | - Lena Mäler
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden .,Department of Chemistry, Umeå University, Umeå, Sweden
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27
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Gupta SK, Angara RK, Yousuf S, Reddy CG, Ranjan A. Ectopic Expression of Rv0023 Mediates Isoniazid/Ethionamide Tolerance via Altering NADH/NAD + Levels in Mycobacterium smegmatis. Front Microbiol 2020; 11:3. [PMID: 32117088 PMCID: PMC7020754 DOI: 10.3389/fmicb.2020.00003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Accepted: 01/03/2020] [Indexed: 02/01/2023] Open
Abstract
Tuberculosis (TB) caused by Mycobacterium tuberculosis (Mtb) accounts for nearly 1.2 million deaths per annum worldwide. Due to the emergence of multidrug-resistant (MDR) Mtb strains, TB, a curable and avertable disease, remains one of the leading causes of morbidity and mortality. Isoniazid (INH) is a first-line anti-TB drug while ethionamide (ETH) is used as a second-line anti-TB drug. INH and ETH resistance develop through a network of genes involved in various biosynthetic pathways. In this study, we identified Rv0023, an Mtb protein belonging to the xenobiotic response element (XRE) family of transcription regulators, which has a role in generating higher tolerance toward INH and ETH in Mycobacterium smegmatis (Msmeg). Overexpression of Rv0023 in Msmeg leads to the development of INH- and ETH-tolerant strains. The strains expressing Rv0023 have a higher ratio of NADH/NAD+, and this physiological event is known to play a crucial role in the development of INH/ETH co-resistance in Msmeg. Gene expression analysis of some target genes revealed reduction in the expression of the ndh gene, but no direct interaction was observed between Rv0023 and the ndh promoter region. Rv0023 is divergently expressed to Rv0022c (whiB5) and we observed a direct interaction between the recombinant Rv0023 protein with the upstream region of Rv0022c, confirmed using reporter constructs of Msmeg. However, we found no indication that this interaction might play a role in the development of INH/ETH drug tolerance.
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Affiliation(s)
- Shailesh Kumar Gupta
- Computational and Functional Genomics Group, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, India.,Graduate Studies, Manipal Academy of Higher Education, Manipal, India
| | - Rajendra Kumar Angara
- Computational and Functional Genomics Group, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, India
| | - Suhail Yousuf
- Computational and Functional Genomics Group, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, India
| | - Chilakala Gangi Reddy
- Computational and Functional Genomics Group, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, India.,Regional Centre for Biotechnology, Faridabad, India
| | - Akash Ranjan
- Computational and Functional Genomics Group, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, India
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28
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Techniques to Understand Mycobacterial Lipids and Use of Lipid-Based Nanoformulations for Tuberculosis Management. Nanobiomedicine (Rij) 2020. [DOI: 10.1007/978-981-32-9898-9_18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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29
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Regulating colonic dendritic cells by commensal glycosylated large surface layer protein A to sustain gut homeostasis against pathogenic inflammation. Mucosal Immunol 2020; 13:34-46. [PMID: 31619761 PMCID: PMC6917853 DOI: 10.1038/s41385-019-0210-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 08/30/2019] [Accepted: 09/23/2019] [Indexed: 02/04/2023]
Abstract
Microbial interaction with the host through sensing receptors, including SIGNR1, sustains intestinal homeostasis against pathogenic inflammation. The newly discovered commensal Propionibacterium strain, P. UF1, regulates the intestinal immunity against pathogen challenge. However, the molecular events driving intestinal phagocytic cell response, including colonic dendritic cells (DCs), by this bacterium are still elusive. Here, we demonstrate that the glycosylation of bacterial large surface layer protein A (LspA) by protein O-mannosyltransferase 1 (Pmt1) regulates the interaction with SIGNR1, resulting in the control of DC transcriptomic and metabolomic machineries. Programmed DCs promote protective T cell response to intestinal Listeria infection and resist chemically induced colitis in mice. Thus, our findings may highlight a novel molecular mechanism by which commensal surface glycosylation interacting with SIGNR1 directs the intestinal homeostasis to potentially protect the host against proinflammatory signals inducing colonic tissue damage.
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30
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Eagen WJ, Baumoel LR, Osman SH, Rahlwes KC, Morita YS. Deletion of PimE mannosyltransferase results in increased copper sensitivity in Mycobacterium smegmatis. FEMS Microbiol Lett 2019; 365:4830098. [PMID: 29390083 DOI: 10.1093/femsle/fny025] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Accepted: 01/26/2018] [Indexed: 12/20/2022] Open
Abstract
The unique cell envelope structure of Mycobacterium tuberculosis is fundamental to its pathogenesis. Phosphatidylinositol (PI)-anchored glycolipids, such as phosphatidylinositol mannosides (PIMs), lipomannan and lipoarabinomannan, are essential components of the cell envelope widely conserved among mycobacteria, but their roles in the cell envelope integrity are not fully understood. We previously identified PimE in Mycobacterium smegmatis, a nonpathogenic model organism, as a mannosyltransferase that catalyzes the fifth mannose transfer for the biosynthesis of hexamannosyl PIMs. Our analyses, reported here, further demonstrate that the growth of the pimE deletion mutant (ΔpimE) is defective in the presence of copper. We first found that the small colony phenotype of ΔpimE on a solid Middlebrook 7H10 agar surface was alleviated when grown on M63 agar. Comparative analysis of the two media led us to identify copper in Middlebrook 7H10 as the cause of growth retardation seen in ΔpimE. We further demonstrated that ΔpimE is sensitized to several antibiotics, but the increased sensitivities were independent of the presence of copper. We conclude that the deletion of the pimE gene does not cause growth defects under optimal growth conditions, but makes the cell envelope vulnerable to toxic compounds such as copper and antibiotics.
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Affiliation(s)
- William J Eagen
- Department of Microbiology, University of Massachusetts, Amherst, MA 01003, USA
| | - Lisa R Baumoel
- Department of Microbiology, University of Massachusetts, Amherst, MA 01003, USA
| | - Sarah H Osman
- Department of Microbiology, University of Massachusetts, Amherst, MA 01003, USA
| | - Kathryn C Rahlwes
- Department of Microbiology, University of Massachusetts, Amherst, MA 01003, USA
| | - Yasu S Morita
- Department of Microbiology, University of Massachusetts, Amherst, MA 01003, USA
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31
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Abstract
Actinobacteria is a group of diverse bacteria. Most species in this class of bacteria are filamentous aerobes found in soil, including the genus Streptomyces perhaps best known for their fascinating capabilities of producing antibiotics. These bacteria typically have a Gram-positive cell envelope, comprised of a plasma membrane and a thick peptidoglycan layer. However, there is a notable exception of the Corynebacteriales order, which has evolved a unique type of outer membrane likely as a consequence of convergent evolution. In this chapter, we will focus on the unique cell envelope of this order. This cell envelope features the peptidoglycan layer that is covalently modified by an additional layer of arabinogalactan . Furthermore, the arabinogalactan layer provides the platform for the covalent attachment of mycolic acids , some of the longest natural fatty acids that can contain ~100 carbon atoms per molecule. Mycolic acids are thought to be the main component of the outer membrane, which is composed of many additional lipids including trehalose dimycolate, also known as the cord factor. Importantly, a subset of bacteria in the Corynebacteriales order are pathogens of human and domestic animals, including Mycobacterium tuberculosis. The surface coat of these pathogens are the first point of contact with the host immune system, and we now know a number of host receptors specific to molecular patterns exposed on the pathogen's surface, highlighting the importance of understanding how the cell envelope of Actinobacteria is structured and constructed. This chapter describes the main structural and biosynthetic features of major components found in the actinobacterial cell envelopes and highlights the key differences between them.
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Affiliation(s)
- Kathryn C Rahlwes
- Department of Microbiology, University of Massachusetts, 639 North Pleasant Street, Amherst, MA, 01003, USA
| | - Ian L Sparks
- Department of Microbiology, University of Massachusetts, 639 North Pleasant Street, Amherst, MA, 01003, USA
| | - Yasu S Morita
- Department of Microbiology, University of Massachusetts, 639 North Pleasant Street, Amherst, MA, 01003, USA.
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32
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Ganief N, Sjouerman J, Albeldas C, Nakedi KC, Hermann C, Calder B, Blackburn JM, Soares NC. Associating H 2O 2-and NO-related changes in the proteome of Mycobacterium smegmatis with enhanced survival in macrophage. Emerg Microbes Infect 2018; 7:212. [PMID: 30546046 PMCID: PMC6292918 DOI: 10.1038/s41426-018-0210-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 10/26/2018] [Accepted: 11/05/2018] [Indexed: 01/24/2023]
Abstract
Mycobacterium manages to evade the host cell immune system, partially owing to its ability to survive redox stress after macrophage engulfment. Exposure to redox stress has been linked to later replication, persistence, and latent infection. In this work, mass spectrometry was used to elucidate the cell-wide changes that occur in response to sublethal doses of hydrogen peroxide and nitric oxide over time, with Mycobacterium smegmatis being used as a model organism. A total of 3135 proteins were confidently assigned, of which 1713, 1674, and 1713 were identified under NO, H2O2, and control conditions, respectively. Both treatment conditions resulted in changes of protein expression from the DosR regulon as well as those related to lipid metabolism. Complementary to the changes in the proteome, sublethal exposure to NO and H2O2 improved the survival of the bacteria after macrophage infection. Our data indicate that pre-exposure to sublethal doses of these redox stressors causes an alteration in the expression of proteins related to lipid metabolism, suggesting a link between altered lipid metabolism and enhanced survival in macrophages.
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Affiliation(s)
- Naadir Ganief
- Division of Chemical & System Biology, Department of Integrative Biomedical Science, University of Cape Town, Cape Town, South Africa
| | - Jessica Sjouerman
- Division of Chemical & System Biology, Department of Integrative Biomedical Science, University of Cape Town, Cape Town, South Africa
| | - Claudia Albeldas
- Division of Chemical & System Biology, Department of Integrative Biomedical Science, University of Cape Town, Cape Town, South Africa
| | - Kehilwe C Nakedi
- Division of Chemical & System Biology, Department of Integrative Biomedical Science, University of Cape Town, Cape Town, South Africa
| | - Clemens Hermann
- Division of Chemical & System Biology, Department of Integrative Biomedical Science, University of Cape Town, Cape Town, South Africa
| | - Bridget Calder
- Division of Chemical & System Biology, Department of Integrative Biomedical Science, University of Cape Town, Cape Town, South Africa
| | - Jonathan M Blackburn
- Division of Chemical & System Biology, Department of Integrative Biomedical Science, University of Cape Town, Cape Town, South Africa.
- Institute of Infectious Disease & Molecular Medicine, University of Cape Town, Cape Town, South Africa.
| | - Nelson C Soares
- Division of Chemical & System Biology, Department of Integrative Biomedical Science, University of Cape Town, Cape Town, South Africa.
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33
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Decout A, Silva-Gomes S, Drocourt D, Blattes E, Rivière M, Prandi J, Larrouy-Maumus G, Caminade AM, Hamasur B, Källenius G, Kaur D, Dobos KM, Lucas M, Sutcliffe IC, Besra GS, Appelmelk BJ, Gilleron M, Jackson M, Vercellone A, Tiraby G, Nigou J. Deciphering the molecular basis of mycobacteria and lipoglycan recognition by the C-type lectin Dectin-2. Sci Rep 2018; 8:16840. [PMID: 30443026 PMCID: PMC6237770 DOI: 10.1038/s41598-018-35393-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Accepted: 11/05/2018] [Indexed: 01/04/2023] Open
Abstract
Dectin-2 is a C-type lectin involved in the recognition of several pathogens such as Aspergillus fumigatus, Candida albicans, Schistosoma mansonii, and Mycobacterium tuberculosis that triggers Th17 immune responses. Identifying pathogen ligands and understanding the molecular basis of their recognition is one of the current challenges. Purified M. tuberculosis mannose-capped lipoarabinomannan (ManLAM) was shown to induce signaling via Dectin-2, an activity that requires the (α1 → 2)-linked mannosides forming the caps. Here, using isogenic M. tuberculosis mutant strains, we demonstrate that ManLAM is a bona fide and actually the sole ligand mediating bacilli recognition by Dectin-2, although M. tuberculosis produces a variety of cell envelope mannoconjugates, such as phosphatidyl-myo-inositol hexamannosides, lipomannan or manno(lipo)proteins, that bear (α1 → 2)-linked mannosides. In addition, we found that Dectin-2 can recognize lipoglycans from other bacterial species, such as Saccharotrix aerocolonigenes or the human opportunistic pathogen Tsukamurella paurometabola, suggesting that lipoglycans are prototypical Dectin-2 ligands. Finally, from a structure/function relationship perspective, we show, using lipoglycan variants and synthetic mannodendrimers, that dimannoside caps and multivalent interaction are required for ligand binding to and signaling via Dectin-2. Better understanding of the molecular basis of ligand recognition by Dectin-2 will pave the way for the rational design of potent adjuvants targeting this receptor.
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Affiliation(s)
- Alexiane Decout
- Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, Université Paul Sabatier, 31077, Toulouse, France.,InvivoGen, Research Department, 31400, Toulouse, France.,Global Health Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Sandro Silva-Gomes
- Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, Université Paul Sabatier, 31077, Toulouse, France.,GlaxoSmithKline (GSK), Stevenage Herts, SG1 2NY, UK
| | | | - Emilyne Blattes
- Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, Université Paul Sabatier, 31077, Toulouse, France.,Innovative Medecine for Tuberculosis (iM4TB), Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Michel Rivière
- Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, Université Paul Sabatier, 31077, Toulouse, France
| | - Jacques Prandi
- Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, Université Paul Sabatier, 31077, Toulouse, France
| | - Gérald Larrouy-Maumus
- Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, Université Paul Sabatier, 31077, Toulouse, France.,Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, London, SW7 2AZ, UK
| | - Anne-Marie Caminade
- Laboratoire de Chimie de Coordination, Université de Toulouse, CNRS, Université Paul Sabatier, 31077, Toulouse, France
| | - Beston Hamasur
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, 171 77, Stockholm, Sweden.,Biopromic AB, 171 65, Solna, Sweden
| | - Gunilla Källenius
- Department of Medicine, Karolinska Institutet Solna 171 76, Stockholm, Sweden
| | - Devinder Kaur
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, 80523-1682, USA.,Massachusetts Supranational TB Reference Laboratory, University of Massachusetts Medical School, Jamaica Plain, MA, 0213, USA
| | - Karen M Dobos
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, 80523-1682, USA
| | - Megan Lucas
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, 80523-1682, USA
| | - Iain C Sutcliffe
- Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, NE1 8ST, UK
| | - Gurdyal S Besra
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Ben J Appelmelk
- Department of Medical Microbiology and Infection Control, VU University Medical Center, 1081 BT, Amsterdam, The Netherlands
| | - Martine Gilleron
- Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, Université Paul Sabatier, 31077, Toulouse, France
| | - Mary Jackson
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, 80523-1682, USA
| | - Alain Vercellone
- Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, Université Paul Sabatier, 31077, Toulouse, France
| | - Gérard Tiraby
- InvivoGen, Research Department, 31400, Toulouse, France
| | - Jérôme Nigou
- Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, Université Paul Sabatier, 31077, Toulouse, France.
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34
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Tersa M, Raich L, Albesa-Jové D, Trastoy B, Prandi J, Gilleron M, Rovira C, Guerin ME. The Molecular Mechanism of Substrate Recognition and Catalysis of the Membrane Acyltransferase PatA from Mycobacteria. ACS Chem Biol 2018; 13:131-140. [PMID: 29185694 DOI: 10.1021/acschembio.7b00578] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Glycolipids play a central role in a variety of important biological processes in all living organisms. PatA is a membrane acyltransferase involved in the biosynthesis of phosphatidyl-myo-inositol mannosides (PIMs), key structural elements, and virulence factors of Mycobacterium tuberculosis. PatA catalyzes the transfer of a palmitoyl moiety from palmitoyl-CoA to the 6-position of the mannose ring linked to the 2-position of inositol in PIM1/PIM2. We report here the crystal structure of PatA in the presence of 6-O-palmitoyl-α-d-mannopyranoside, unraveling the acceptor binding mechanism. The acceptor mannose ring localizes in a cavity at the end of a surface-exposed long groove where the active site is located, whereas the palmitate moiety accommodates into a hydrophobic pocket deeply buried in the α/β core of the protein. Both fatty acyl chains of the PIM2 acceptor are essential for the reaction to take place, highlighting their critical role in the generation of a competent active site. By the use of combined structural and quantum-mechanics/molecular-mechanics (QM/MM) metadynamics, we unravel the catalytic mechanism of PatA at the atomic-electronic level. Our study provides a detailed structural rationale for a stepwise reaction, with the generation of a tetrahedral transition state for the rate-determining step. Finally, the crystal structure of PatA in the presence of β-d-mannopyranose and palmitate suggests an inhibitory mechanism for the enzyme, providing exciting possibilities for inhibitor design and the discovery of chemotherapeutic agents against this major human pathogen.
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Affiliation(s)
- Montse Tersa
- Structural Biology
Unit, CIC bioGUNE, Bizkaia Technology Park, 48160 Derio, Spain
| | - Lluís Raich
- Departament
de Química Inorgànica i Orgànica (Secció
de Química Orgànica) and IQTCUB, Universitat de Barcelona, 08028 Barcelona, Spain
| | - David Albesa-Jové
- Structural Biology
Unit, CIC bioGUNE, Bizkaia Technology Park, 48160 Derio, Spain
- Unidad de Biofísica, Centro Mixto Consejo Superior de Investigaciones Científicas - Universidad del País Vasco/Euskal Herriko Unibertsitatea (CSIC, UPV/EHU), Barrio Sarriena s/n, Leioa, Bizkaia 48940, Spain
- Departamento de
Bioquímica, Universidad del País Vasco, Leioa, Spain
- IKERBASQUE, Basque Foundation for Science, 48013, Bilbao, Spain
| | - Beatriz Trastoy
- Structural Biology
Unit, CIC bioGUNE, Bizkaia Technology Park, 48160 Derio, Spain
| | - Jacques Prandi
- Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, UPS, 205 route de Narbonne, F-31077 Toulouse, France
| | - Martine Gilleron
- Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, UPS, 205 route de Narbonne, F-31077 Toulouse, France
| | - Carme Rovira
- Departament
de Química Inorgànica i Orgànica (Secció
de Química Orgànica) and IQTCUB, Universitat de Barcelona, 08028 Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), 08020 Barcelona, Spain
| | - Marcelo E. Guerin
- Structural Biology
Unit, CIC bioGUNE, Bizkaia Technology Park, 48160 Derio, Spain
- Unidad de Biofísica, Centro Mixto Consejo Superior de Investigaciones Científicas - Universidad del País Vasco/Euskal Herriko Unibertsitatea (CSIC, UPV/EHU), Barrio Sarriena s/n, Leioa, Bizkaia 48940, Spain
- Departamento de
Bioquímica, Universidad del País Vasco, Leioa, Spain
- IKERBASQUE, Basque Foundation for Science, 48013, Bilbao, Spain
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35
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An IclR like protein from mycobacteria regulates leuCD operon and induces dormancy-like growth arrest in Mycobacterium smegmatis. Tuberculosis (Edinb) 2018. [DOI: 10.1016/j.tube.2017.10.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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36
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Goins CM, Schreidah CM, Dajnowicz S, Ronning DR. Structural basis for lipid binding and mechanism of the Mycobacterium tuberculosis Rv3802 phospholipase. J Biol Chem 2017; 293:1363-1372. [PMID: 29247008 DOI: 10.1074/jbc.ra117.000240] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Revised: 12/05/2017] [Indexed: 11/06/2022] Open
Abstract
The Mycobacterium tuberculosis rv3802c gene encodes an essential enzyme with thioesterase and phospholipase A activity. Overexpression of Rv3802 orthologs in Mycobacterium smegmatis and Corynebacterium glutamicum increases mycolate content and decreases glycerophospholipids. Although a role in modulating the lipid composition of the unique mycomembrane has been proposed, the true biological function of Rv3802 remains uncertain. In this study, we present the first M. tuberculosis Rv3802 X-ray crystal structure, solved to 1.7 Å resolution. On the basis of the binding of PEG molecules to Rv3802, we identified its lipid-binding site and the structural basis for phosphatidyl-based substrate binding and phospholipase A activity. We found that movement of the α8-helix affords lipid binding and is required for catalytic turnover through covalent tethering. We gained insights into the mechanism of acyl hydrolysis by observing differing arrangements of PEG and water molecules within the active site. This study provides structural insights into biological function and facilitates future structure-based drug design toward Rv3802.
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Affiliation(s)
- Christopher M Goins
- From the Department of Chemistry and Biochemistry, University of Toledo, Toledo, Ohio 43606-3390 and
| | - Celine M Schreidah
- From the Department of Chemistry and Biochemistry, University of Toledo, Toledo, Ohio 43606-3390 and
| | - Steven Dajnowicz
- From the Department of Chemistry and Biochemistry, University of Toledo, Toledo, Ohio 43606-3390 and.,the Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831
| | - Donald R Ronning
- From the Department of Chemistry and Biochemistry, University of Toledo, Toledo, Ohio 43606-3390 and
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37
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N-Acetylglucosamine-1-Phosphate Transferase, WecA, as a Validated Drug Target in Mycobacterium tuberculosis. Antimicrob Agents Chemother 2017; 61:AAC.01310-17. [PMID: 28874370 DOI: 10.1128/aac.01310-17] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2017] [Accepted: 08/25/2017] [Indexed: 12/24/2022] Open
Abstract
The mycobacterial phosphoglycosyltransferase WecA, which initiates arabinogalactan biosynthesis in Mycobacterium tuberculosis, has been proposed as a target of the caprazamycin derivative CPZEN-45, a preclinical drug candidate for the treatment of tuberculosis. In this report, we describe the functional characterization of mycobacterial WecA and confirm the essentiality of its encoding gene in M. tuberculosis by demonstrating that the transcriptional silencing of wecA is bactericidal in vitro and in macrophages. Silencing wecA also conferred hypersensitivity of M. tuberculosis to the drug tunicamycin, confirming its target selectivity for WecA in whole cells. Simple radiometric assays performed with mycobacterial membranes and commercially available substrates allowed chemical validation of other putative WecA inhibitors and resolved their selectivity toward WecA versus another attractive cell wall target, translocase I, which catalyzes the first membrane step in the biosynthesis of peptidoglycan. These assays and the mutant strain described herein will be useful for identifying potential antitubercular leads by screening chemical libraries for novel WecA inhibitors.
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38
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Rahlwes KC, Ha SA, Motooka D, Mayfield JA, Baumoel LR, Strickland JN, Torres-Ocampo AP, Nakamura S, Morita YS. The cell envelope-associated phospholipid-binding protein LmeA is required for mannan polymerization in mycobacteria. J Biol Chem 2017; 292:17407-17417. [PMID: 28855252 DOI: 10.1074/jbc.m117.804377] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Revised: 08/28/2017] [Indexed: 11/06/2022] Open
Abstract
The integrity of the distinguishing, multilaminate cell envelope surrounding mycobacteria is critical to their survival and pathogenesis. The prevalence of phosphatidylinositol mannosides in the cell envelope suggests an important role in the mycobacterial life cycle. Indeed, deletion of the pimE gene (ΔpimE) encoding the first committed step in phosphatidylinositol hexamannoside biosynthesis in Mycobacterium smegmatis results in the formation of smaller colonies than wild-type colonies on Middlebrook 7H10 agar. To further investigate potential contributors to cell-envelope mannan biosynthesis while taking advantage of this colony morphology defect, we isolated spontaneous suppressor mutants of ΔpimE that reverted to wild-type colony size. Of 22 suppressor mutants, 6 accumulated significantly shorter lipomannan or lipoarabinomannan. Genome sequencing of these mutants revealed mutations in genes involved in the lipomannan/lipoarabinomannan biosynthesis, such as those encoding the arabinosyltransferase EmbC and the mannosyltransferase MptA. Furthermore, we identified three mutants carrying a mutation in a previously uncharacterized gene, MSMEG_5785, that we designated lmeA Complementation of these suppressor mutants with lmeA restored the original ΔpimE phenotypes and deletion of lmeA in wild-type M. smegmatis resulted in smaller lipomannan, as observed in the suppressor mutants. LmeA carries a predicted N-terminal signal peptide, and density gradient fractionation and detergent extractability experiments indicated that LmeA localizes to the cell envelope. Using a lipid ELISA, we found that LmeA binds to plasma membrane phospholipids, such as phosphatidylethanolamine and phosphatidylinositol. LmeA is widespread throughout the Corynebacteriales; therefore, we concluded that LmeA is an evolutionarily conserved cell-envelope protein critical for controlling the mannan chain length of lipomannan/lipoarabinomannan.
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Affiliation(s)
- Kathryn C Rahlwes
- From the Department of Microbiology, University of Massachusetts, Amherst, MA 01003
| | - Stephanie A Ha
- From the Department of Microbiology, University of Massachusetts, Amherst, MA 01003
| | - Daisuke Motooka
- the Department of Infection Metagenomics, Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871, Japan
| | - Jacob A Mayfield
- the Division of Rheumatology, Immunology, and Allergy, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02445
| | - Lisa R Baumoel
- From the Department of Microbiology, University of Massachusetts, Amherst, MA 01003
| | - Justin N Strickland
- From the Department of Microbiology, University of Massachusetts, Amherst, MA 01003
| | - Ana P Torres-Ocampo
- From the Department of Microbiology, University of Massachusetts, Amherst, MA 01003
| | - Shota Nakamura
- the Department of Infection Metagenomics, Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871, Japan
| | - Yasu S Morita
- From the Department of Microbiology, University of Massachusetts, Amherst, MA 01003,
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39
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Anti-tubercular drug discovery: in silico implications and challenges. Eur J Pharm Sci 2017; 104:1-15. [PMID: 28341614 DOI: 10.1016/j.ejps.2017.03.028] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Revised: 03/08/2017] [Accepted: 03/19/2017] [Indexed: 12/18/2022]
Abstract
Tuberculosis (TB) has been reported as a major public health concern, especially in the developing countries. WHO report on tuberculosis 2016 shows a high mortality rate caused by TB leading to 1.8 million deaths worldwide (including deaths due to TB in HIV positive individuals), which is one of the top 10 causes of mortality in 2015. However, the main therapy used for the treatment of TB is still the Direct Observed Therapy Short-course (DOTS) that consists of four main first-line drugs. Due to the prolonged and unorganized use of these drugs, Mycobacterium tuberculosis (Mtb) has developed drug-resistance against them. To overcome this drug-resistance, efforts are continuously being made to develop new therapeutics. New drug-targets of Mtb are pursued by the researchers to develop their inhibitors. For this, new methodologies that comprise of the computational drug designing techniques are vigorously applied. A major limitation that is found with these techniques is the inability of the newly identified target-based inhibitors to inhibit the whole cell bacteria. A foremost factor for this limitation is the inability of these inhibitors to penetrate the bacterial cell wall. In this regard, various strategies to overcome this limitation have been discussed in detail in this review, along with new targets and new methodologies. A bunch of in silico tools available for the prediction of physicochemical properties that need to be explored to deal with the permeability issue of the Mtb inhibitors has also been discussed.
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40
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Cashmore TJ, Klatt S, Yamaryo-Botte Y, Brammananth R, Rainczuk AK, McConville MJ, Crellin PK, Coppel RL. Identification of a Membrane Protein Required for Lipomannan Maturation and Lipoarabinomannan Synthesis in Corynebacterineae. J Biol Chem 2017; 292:4976-4986. [PMID: 28167532 DOI: 10.1074/jbc.m116.772202] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 01/26/2017] [Indexed: 12/16/2022] Open
Abstract
Mycobacterium tuberculosis and related Corynebacterineae synthesize a family of lipomannans (LM) and lipoarabinomannans (LAM) that are abundant components of the multilaminate cell wall and essential virulence factors in pathogenic species. Here we describe a new membrane protein, highly conserved in all Corynebacterineae, that is required for synthesis of full-length LM and LAM. Deletion of the Corynebacterium glutamicum NCgl2760 gene resulted in a complete loss of mature LM/LAM and the appearance of a truncated LM (t-LM). Complementation of the mutant with the NCgl2760 gene fully restored LM/LAM synthesis. Structural studies, including monosaccharide analysis, methylation linkage analysis, and mass spectrometry of native LM species, indicated that the ΔNCgl2760 t-LM comprised a series of short LM species (8-27 residues long) containing an α1-6-linked mannose backbone with greatly reduced α1-2-mannose side chains and no arabinose caps. The structure of the ΔNCgl2760 t-LM was similar to that of the t-LM produced by a C. glutamicum mutant lacking the mptA gene, encoding a membrane α1-6-mannosyltransferase involved in extending the α1-6-mannan backbone of LM intermediates. Interestingly, NCgl2760 lacks any motifs or homology to other proteins of known function. Attempts to delete the NCgl2760 orthologue in Mycobacterium smegmatis were unsuccessful, consistent with previous studies indicating that the M. tuberculosis orthologue, Rv0227c, is an essential gene. Together, these data suggest that NCgl2760/Rv0227c plays a critical role in the elongation of the mannan backbone of mycobacterial and corynebacterial LM, further highlighting the complexity of lipoglycan pathways of Corynebacterineae.
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Affiliation(s)
- Tamaryn J Cashmore
- From the Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Victoria 3800 and
| | - Stephan Klatt
- the Department of Biochemistry and Molecular Biology, Bio21 Institute of Molecular Sciences and Biotechnology, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Yoshiki Yamaryo-Botte
- the Department of Biochemistry and Molecular Biology, Bio21 Institute of Molecular Sciences and Biotechnology, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Rajini Brammananth
- From the Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Victoria 3800 and
| | - Arek K Rainczuk
- From the Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Victoria 3800 and
| | - Malcolm J McConville
- the Department of Biochemistry and Molecular Biology, Bio21 Institute of Molecular Sciences and Biotechnology, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Paul K Crellin
- From the Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Victoria 3800 and
| | - Ross L Coppel
- From the Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Victoria 3800 and
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41
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Abstract
Mycobacterium tuberculosis (Mtb), the etiological agent of tuberculosis (TB), is recognized as a global health emergency as promoted by the World Health Organization. Over 1 million deaths per year, along with the emergence of multi- and extensively-drug resistant strains of Mtb, have triggered intensive research into the pathogenicity and biochemistry of this microorganism, guiding the development of anti-TB chemotherapeutic agents. The essential mycobacterial cell wall, sharing some common features with all bacteria, represents an apparent ‘Achilles heel’ that has been targeted by TB chemotherapy since the advent of TB treatment. This complex structure composed of three distinct layers, peptidoglycan, arabinogalactan and mycolic acids, is vital in supporting cell growth, virulence and providing a barrier to antibiotics. The fundamental nature of cell wall synthesis and assembly has rendered the mycobacterial cell wall as the most widely exploited target of anti-TB drugs. This review provides an overview of the biosynthesis of the prominent cell wall components, highlighting the inhibitory mechanisms of existing clinical drugs and illustrating the potential of other unexploited enzymes as future drug targets.
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42
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Structural basis of phosphatidyl-myo-inositol mannosides biosynthesis in mycobacteria. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1862:1355-1367. [PMID: 27826050 DOI: 10.1016/j.bbalip.2016.11.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 10/29/2016] [Accepted: 11/02/2016] [Indexed: 11/22/2022]
Abstract
Phosphatidyl-myo-inositol mannosides (PIMs) are glycolipids of unique chemical structure found in the inner and outer membranes of the cell envelope of all Mycobacterium species. The PIM family of glycolipids comprises phosphatidyl-myo-inositol mono-, di-, tri-, tetra-, penta-, and hexamannosides with different degrees of acylation. PIMs are considered not only essential structural components of the cell envelope but also the precursors of lipomannan and lipoarabinomannan, two major lipoglycans implicated in host-pathogen interactions. Since the description of the complete chemical structure of PIMs, major efforts have been committed to defining the molecular bases of its biosynthetic pathway. The structural characterization of the integral membrane phosphatidyl-myo-inositol phosphate synthase (PIPS), and that of three enzymes working at the protein-membrane interface, the phosphatidyl-myo-inositol mannosyltransferases A and B, and the acyltransferase PatA, established the basis of the early steps of the PIM pathway at the molecular level. This article is part of a Special Issue entitled: Bacterial Lipids edited by Russell E. Bishop.
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Mikušová K, Ekins S. Learning from the past for TB drug discovery in the future. Drug Discov Today 2016; 22:534-545. [PMID: 27717850 DOI: 10.1016/j.drudis.2016.09.025] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Revised: 09/25/2016] [Accepted: 09/28/2016] [Indexed: 12/14/2022]
Abstract
Tuberculosis drug discovery has shifted in recent years from a primarily target-based approach to one that uses phenotypic high-throughput screens. As examples of this, through our EU-funded FP7 collaborations, New Medicines for Tuberculosis was target-based and our more-recent More Medicines for Tuberculosis project predominantly used phenotypic screening. From these projects we have examples of success (DprE1) and failure (PimA) going from drug to target and from target to drug, respectively. It is clear that we still have much to learn about the drug targets and the complex effects of the drugs on Mycobacterium tuberculosis. We propose a more integrated approach that learns from earlier drug discovery efforts that could help to move drug discovery forward.
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Affiliation(s)
- Katarína Mikušová
- Department of Biochemistry, Faculty of Natural Sciences, Comenius University in Bratislava, Mlynská dolina, Ilkovičova 6, 84215 Bratislava, Slovakia
| | - Sean Ekins
- Collaborative Drug Discovery, Inc., 1633 Bayshore Highway, Suite 342, Burlingame, CA 94010, USA; Collaborations in Chemistry, 5616 Hilltop Needmore Road, Fuquay Varina, NC 27526, USA.
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Singh V, Mizrahi V. Identification and validation of novel drug targets in Mycobacterium tuberculosis. Drug Discov Today 2016; 22:503-509. [PMID: 27649943 DOI: 10.1016/j.drudis.2016.09.010] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Revised: 08/28/2016] [Accepted: 09/12/2016] [Indexed: 10/21/2022]
Abstract
Tuberculosis (TB) is a global epidemic associated increasingly with resistance to first- and second-line antitubercular drugs. The magnitude of this global health threat underscores the urgent need to discover new antimycobacterial agents that have novel mechanisms of action (MOA). In this review, we highlight some of the key advances that have enabled the strengths of target-led and phenotypic approaches to TB drug discovery to be harnessed both independently and in combination. Critically, these promise to fuel the front-end of the TB drug pipeline with new, pharmacologically validated drug targets together with lead compounds that act on these targets.
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Affiliation(s)
- Vinayak Singh
- MRC/NHLS/UCT Molecular Mycobacteriology Research Unit & DST/NRF Centre of Excellence for Biomedical TB Research, Institute of Infectious Disease and Molecular Medicine & Department of Pathology, University of Cape Town, Anzio Road, Observatory 7925, South Africa.
| | - Valerie Mizrahi
- MRC/NHLS/UCT Molecular Mycobacteriology Research Unit & DST/NRF Centre of Excellence for Biomedical TB Research, Institute of Infectious Disease and Molecular Medicine & Department of Pathology, University of Cape Town, Anzio Road, Observatory 7925, South Africa
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Rodrigo-Unzueta A, Martínez MA, Comino N, Alzari PM, Chenal A, Guerin ME. Molecular Basis of Membrane Association by the Phosphatidylinositol Mannosyltransferase PimA Enzyme from Mycobacteria. J Biol Chem 2016; 291:13955-13963. [PMID: 27189944 DOI: 10.1074/jbc.m116.723676] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Indexed: 01/09/2023] Open
Abstract
Phosphatidyl-myo-inositol mannosyltransferase A (PimA) is an essential glycosyltransferase that initiates the biosynthetic pathway of phosphatidyl-myo-inositol mannoside, lipomannan, and lipoarabinomannan, which are key glycolipids/lipoglycans of the mycobacterial cell envelope. PimA belongs to a large family of membrane-associated glycosyltransferases for which the understanding of the molecular mechanism and conformational changes that govern substrate/membrane recognition and catalysis remains a major challenge. Here, we determined that PimA preferentially binds to negatively charged phosphatidyl-myo-inositol substrate and non-substrate membrane model systems (small unilamellar vesicle) through its N-terminal domain, inducing an important structural reorganization of anionic phospholipids. By using a combination of single-point mutagenesis, circular dichroism, and a variety of fluorescence spectroscopy techniques, we determined that this interaction is mainly mediated by an amphipathic α-helix (α2), which undergoes a substantial conformational change and localizes in the vicinity of the negatively charged lipid headgroups and the very first carbon atoms of the acyl chains, at the PimA-phospholipid interface. Interestingly, a flexible region within the N-terminal domain, which undergoes β-strand-to-α-helix and α-helix-to-β-strand transitions during catalysis, interacts with anionic phospholipids; however, the effect is markedly less pronounced to that observed for the amphipathic α2, likely reflecting structural plasticity/variability. Altogether, we propose a model in which conformational transitions observed in PimA might reflect a molten globule state that confers to PimA, a higher affinity toward the dynamic and highly fluctuating lipid bilayer.
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Affiliation(s)
- Ane Rodrigo-Unzueta
- Unidad de Biofísica, Centro Mixto Consejo Superior de Investigaciones Científicas-Universidad del País Vasco/Euskal Herriko Unibertsitatea (CSIC, UPV/EHU), Barrio Sarriena s/n, Leioa, Bizkaia 48940, Spain,; Departamento de Bioquímica, Universidad del País Vasco, 48940 Leioa, Vizcaya, Spain
| | - Mariano A Martínez
- Institut Pasteur, Unité de Microbiologie Structurale, CNRS UMR 3528 and University Paris Diderot, Sorbonne Paris Cité, 25 Rue du Dr. Roux, 75724 Paris Cedex 15, France
| | - Natalia Comino
- Unidad de Biofísica, Centro Mixto Consejo Superior de Investigaciones Científicas-Universidad del País Vasco/Euskal Herriko Unibertsitatea (CSIC, UPV/EHU), Barrio Sarriena s/n, Leioa, Bizkaia 48940, Spain,; Departamento de Bioquímica, Universidad del País Vasco, 48940 Leioa, Vizcaya, Spain,; Structural Biology Unit, Center for Cooperative Research in Biosciences (CIC-bioGUNE), Bizkaia Technology Park, 48160 Derio, Spain
| | - Pedro M Alzari
- Institut Pasteur, Unité de Microbiologie Structurale, CNRS UMR 3528 and University Paris Diderot, Sorbonne Paris Cité, 25 Rue du Dr. Roux, 75724 Paris Cedex 15, France
| | - Alexandre Chenal
- Unité de Biochimie des Interactions Macromoléculaires and CNRS UMR 3528, 28 Rue du Dr. Roux, 75724, Paris Cedex 15, France.
| | - Marcelo E Guerin
- Unidad de Biofísica, Centro Mixto Consejo Superior de Investigaciones Científicas-Universidad del País Vasco/Euskal Herriko Unibertsitatea (CSIC, UPV/EHU), Barrio Sarriena s/n, Leioa, Bizkaia 48940, Spain,; Departamento de Bioquímica, Universidad del País Vasco, 48940 Leioa, Vizcaya, Spain,; Structural Biology Unit, Center for Cooperative Research in Biosciences (CIC-bioGUNE), Bizkaia Technology Park, 48160 Derio, Spain,; IKERBASQUE, Basque Foundation for Science, 48013 Bilbao, Spain.
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Structural basis for selective recognition of acyl chains by the membrane-associated acyltransferase PatA. Nat Commun 2016; 7:10906. [PMID: 26965057 PMCID: PMC4792965 DOI: 10.1038/ncomms10906] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Accepted: 01/30/2016] [Indexed: 11/18/2022] Open
Abstract
The biosynthesis of phospholipids and glycolipids are critical pathways for virtually all cell membranes. PatA is an essential membrane associated acyltransferase involved in the biosynthesis of mycobacterial phosphatidyl-myo-inositol mannosides (PIMs). The enzyme transfers a palmitoyl moiety from palmitoyl–CoA to the 6-position of the mannose ring linked to 2-position of inositol in PIM1/PIM2. We report here the crystal structures of PatA from Mycobacterium smegmatis in the presence of its naturally occurring acyl donor palmitate and a nonhydrolyzable palmitoyl–CoA analog. The structures reveal an α/β architecture, with the acyl chain deeply buried into a hydrophobic pocket that runs perpendicular to a long groove where the active site is located. Enzyme catalysis is mediated by an unprecedented charge relay system, which markedly diverges from the canonical HX4D motif. Our studies establish the mechanistic basis of substrate/membrane recognition and catalysis for an important family of acyltransferases, providing exciting possibilities for inhibitor design. PatA is a membrane-associated acyltransferase that is essential for the biosynthesis of mycobacterial glycolipids. Here, Albesa-Jové et al. describe structures of PatA from Mycobacterium smegmatis in complex with acyl donors and show that catalysis occurs by an unusual charge-relay mechanism.
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Abstract
The cell wall of Mycobacterium tuberculosis is unique in that it differs significantly from those of both Gram-negative and Gram-positive bacteria. The thick, carbohydrate- and lipid-rich cell wall with distinct lipoglycans enables mycobacteria to survive under hostile conditions such as shortage of nutrients and antimicrobial exposure. The key features of this highly complex cell wall are the mycolyl-arabinogalactan-peptidoglycan (mAGP)-based and phosphatidyl-myo-inositol-based macromolecular structures, with the latter possessing potent immunomodulatory properties. These structures are crucial for the growth, viability, and virulence of M. tuberculosis and therefore are often the targets of effective chemotherapeutic agents against tuberculosis. Over the past decade, sophisticated genomic and molecular tools have advanced our understanding of the primary structure and biosynthesis of these macromolecules. The availability of the full genome sequences of various mycobacterial species, including M. tuberculosis, Mycobacterium marinum, and Mycobacterium bovis BCG, have greatly facilitated the identification of large numbers of drug targets and antigens specific to tuberculosis. Techniques to manipulate mycobacteria have also improved extensively; the conditional expression-specialized transduction essentiality test (CESTET) is currently used to determine the essentiality of individual genes. Finally, various biosynthetic assays using either purified proteins or synthetic cell wall acceptors have been developed to study enzyme function. This article focuses on the recent advances in determining the structural details and biosynthesis of arabinogalactan, lipoarabinomannan, and related glycoconjugates.
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Abstract
This article summarizes what is currently known of the structures, physiological roles, involvement in pathogenicity, and biogenesis of a variety of noncovalently bound cell envelope lipids and glycoconjugates of Mycobacterium tuberculosis and other Mycobacterium species. Topics addressed in this article include phospholipids; phosphatidylinositol mannosides; triglycerides; isoprenoids and related compounds (polyprenyl phosphate, menaquinones, carotenoids, noncarotenoid cyclic isoprenoids); acyltrehaloses (lipooligosaccharides, trehalose mono- and di-mycolates, sulfolipids, di- and poly-acyltrehaloses); mannosyl-beta-1-phosphomycoketides; glycopeptidolipids; phthiocerol dimycocerosates, para-hydroxybenzoic acids, and phenolic glycolipids; mycobactins; mycolactones; and capsular polysaccharides.
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Affiliation(s)
- Monika Jankute
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom;
| | - Jonathan A.G. Cox
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom;
| | - James Harrison
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom;
| | - Gurdyal S. Besra
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom;
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Yassin AF, Lapidus A, Han J, Reddy TBK, Huntemann M, Pati A, Ivanova N, Markowitz V, Woyke T, Klenk HP, Kyrpides NC. High quality draft genome sequence of Corynebacterium ulceribovis type strain IMMIB-L1395(T) (DSM 45146(T)). Stand Genomic Sci 2015; 10:50. [PMID: 26380638 PMCID: PMC4572677 DOI: 10.1186/s40793-015-0036-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Accepted: 07/07/2015] [Indexed: 01/21/2023] Open
Abstract
Corynebacterium ulceribovis strain IMMIB L-1395(T) (= DSM 45146(T)) is an aerobic to facultative anaerobic, Gram-positive, non-spore-forming, non-motile rod-shaped bacterium that was isolated from the skin of the udder of a cow, in Schleswig Holstein, Germany. The cell wall of C. ulceribovis contains corynemycolic acids. The cellular fatty acids are those described for the genus Corynebacterium, but tuberculostearic acid is not present. Here we describe the features of C. ulceribovis strain IMMIB L-1395(T), together with genome sequence information and its annotation. The 2,300,451 bp long genome containing 2,104 protein-coding genes and 54 RNA-encoding genes and is part of the Genomic Encyclopedia of Type Strains, Phase I: the one thousand microbial genomes (KMG) project.
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Affiliation(s)
- Atteyet F Yassin
- Institut für Medizinische Mikrobiologie und Immunologie der Universität Bonn, Bonn, Germany
| | - Alla Lapidus
- Theodosius Dobzhansky Center for Genome Bioinformatics, St. Petersburg State University, St. Petersburg, Russia ; Algorithmic Biology Lab, St. Petersburg Academic University, St. Petersburg, Russia
| | - James Han
- Department of Energy Joint Genome Institute, Genome Biology Program, Walnut Creek, CA USA
| | - T B K Reddy
- Department of Energy Joint Genome Institute, Genome Biology Program, Walnut Creek, CA USA
| | - Marcel Huntemann
- Department of Energy Joint Genome Institute, Genome Biology Program, Walnut Creek, CA USA
| | - Amrita Pati
- Department of Energy Joint Genome Institute, Genome Biology Program, Walnut Creek, CA USA
| | - Natalia Ivanova
- Department of Energy Joint Genome Institute, Genome Biology Program, Walnut Creek, CA USA
| | - Victor Markowitz
- Biological Data Management and Technology Center, Lawrence Berkeley National Laboratory, Berkeley, California USA
| | - Tanja Woyke
- Department of Energy Joint Genome Institute, Genome Biology Program, Walnut Creek, CA USA
| | - Hans-Peter Klenk
- Leibniz Institute DSMZ - German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Nikos C Kyrpides
- Department of Energy Joint Genome Institute, Genome Biology Program, Walnut Creek, CA USA ; Department of Biological Sciences, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia
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