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Sodani M, Misra CS, Nigam G, Fatima Z, Kulkarni S, Rath D. MSMEG_0311 is a conserved essential polar protein involved in mycobacterium cell wall metabolism. Int J Biol Macromol 2024; 260:129583. [PMID: 38242409 DOI: 10.1016/j.ijbiomac.2024.129583] [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: 11/23/2023] [Revised: 01/16/2024] [Accepted: 01/16/2024] [Indexed: 01/21/2024]
Abstract
Cell wall synthesis and cell division are two closely linked pathways in a bacterial cell which distinctly influence the growth and survival of a bacterium. This requires an appreciable coordination between the two processes, more so, in case of mycobacteria with an intricate multi-layered cell wall structure. In this study, we investigated a conserved gene cluster using CRISPR-Cas12 based gene silencing technology to show that knockdown of most of the genes in this cluster leads to growth defects. Investigating conserved genes is important as they likely perform vital cellular functions and the functional insights on such genes can be extended to other mycobacterial species. We characterised one of the genes in the locus, MSMEG_0311. The repression of this gene not only imparts severe growth defect but also changes colony morphology. We demonstrate that the protein preferentially localises to the polar region and investigate its influence on the polar growth of the bacillus. A combination of permeability and drug susceptibility assay strongly suggests a cell wall associated function of this gene which is also corroborated by transcriptomic analysis of the knockdown where a number of cell wall associated genes, particularly iniA and sigF regulon get altered. Considering the gene is highly conserved across mycobacterial species and appears to be essential for growth, it may serve as a potential drug target.
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Affiliation(s)
- Megha Sodani
- Radiation Medicine Centre, Medical Group, Bhabha Atomic Research Centre, Mumbai 400085, Maharashtra, India; Homi Bhabha National Institute, Training School Complex, Anushaktinagar, Mumbai 400094, Maharashtra, India
| | - Chitra S Misra
- Applied Genomics Section, Bio-Science Group, Bhabha Atomic Research Centre, Mumbai 400085, Maharashtra, India
| | - Gaurav Nigam
- Amity Institute of Biotechnology, Amity University Haryana, Gurugram, India
| | - Zeeshan Fatima
- Amity Institute of Biotechnology, Amity University Haryana, Gurugram, India; Department of Laboratory Medicine, Faculty of Applied Medical Sciences, University of Bisha, Bisha, Saudi Arabia
| | - Savita Kulkarni
- Radiation Medicine Centre, Medical Group, Bhabha Atomic Research Centre, Mumbai 400085, Maharashtra, India; Homi Bhabha National Institute, Training School Complex, Anushaktinagar, Mumbai 400094, Maharashtra, India.
| | - Devashish Rath
- Homi Bhabha National Institute, Training School Complex, Anushaktinagar, Mumbai 400094, Maharashtra, India; Applied Genomics Section, Bio-Science Group, Bhabha Atomic Research Centre, Mumbai 400085, Maharashtra, India.
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2
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Zhang L, Rao Z. Structural biology and inhibition of the Mtb cell wall glycoconjugates biosynthesis on the membrane. Curr Opin Struct Biol 2023; 82:102670. [PMID: 37542906 DOI: 10.1016/j.sbi.2023.102670] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2023] [Revised: 06/08/2023] [Accepted: 07/10/2023] [Indexed: 08/07/2023]
Abstract
Glycoconjugates are the dominant components of the Mycobacterium tuberculosis cell wall. These glycoconjugates are essential for the viability of Mtb and attribute to drug resistance and virulence during infection. The assembly and maturation of the cell wall largely relies on the Mtb plasma membrane. A significant number of membrane-bound glycosyltransferases (GTs) and transporters play pivotal roles in forming the complex glycoconjugates and are targeted by the first-line anti-TB drug and potent drug candidates. Here we summarize the latest structural biology of mycobacterial GTs and transporters, and describe the modes of action of drug and drug candidates that are of substantial clinical value in anti-TB chemotherapeutics.
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Affiliation(s)
- Lu Zhang
- Shanghai Institute for Advanced Immunochemical Studies, School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China.
| | - Zihe Rao
- Laboratory of Structural Biology, Tsinghua University, Beijing 100084, China.
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3
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Yang J, Zhang L, Qiao W, Luo Y. Mycobacterium tuberculosis: Pathogenesis and therapeutic targets. MedComm (Beijing) 2023; 4:e353. [PMID: 37674971 PMCID: PMC10477518 DOI: 10.1002/mco2.353] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 07/31/2023] [Accepted: 08/03/2023] [Indexed: 09/08/2023] Open
Abstract
Tuberculosis (TB) remains a significant public health concern in the 21st century, especially due to drug resistance, coinfection with diseases like immunodeficiency syndrome (AIDS) and coronavirus disease 2019, and the lengthy and costly treatment protocols. In this review, we summarize the pathogenesis of TB infection, therapeutic targets, and corresponding modulators, including first-line medications, current clinical trial drugs and molecules in preclinical assessment. Understanding the mechanisms of Mycobacterium tuberculosis (Mtb) infection and important biological targets can lead to innovative treatments. While most antitubercular agents target pathogen-related processes, host-directed therapy (HDT) modalities addressing immune defense, survival mechanisms, and immunopathology also hold promise. Mtb's adaptation to the human host involves manipulating host cellular mechanisms, and HDT aims to disrupt this manipulation to enhance treatment effectiveness. Our review provides valuable insights for future anti-TB drug development efforts.
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Affiliation(s)
- Jiaxing Yang
- Center of Infectious Diseases and State Key Laboratory of Biotherapy, West China HospitalSichuan UniversityChengduChina
| | - Laiying Zhang
- Center of Infectious Diseases and State Key Laboratory of Biotherapy, West China HospitalSichuan UniversityChengduChina
| | - Wenliang Qiao
- Department of Thoracic Surgery, West China HospitalSichuan UniversityChengduSichuanChina
- Lung Cancer Center, West China HospitalSichuan UniversityChengduSichuanChina
| | - Youfu Luo
- Center of Infectious Diseases and State Key Laboratory of Biotherapy, West China HospitalSichuan UniversityChengduChina
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4
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Jiang S, Shi H, Zhang Q, Wang ZY, Zhang Y, Zhang CY. Rolling circle transcription amplification-directed construction of tandem spinach-based fluorescent light-up biosensor for label-free sensing of β-glucosyltransferase activity. Biosens Bioelectron 2023; 237:115513. [PMID: 37419074 DOI: 10.1016/j.bios.2023.115513] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 06/17/2023] [Accepted: 07/03/2023] [Indexed: 07/09/2023]
Abstract
β-glucosyltransferase (β-GT) can specifically catalyze the conversion of 5-hydroxymethylcytosine (5-hmC) to 5-glucosylhydroxy methylcytosine (5-ghmC), and it is associated with the control of phage-specific gene expression by affecting transcription process in vivo and in vitro. The current strategies for β-GT assay usually involve expensive equipment, laborious treatment, radioactive hazard, and poor sensitivity. Here, we report a Spinach-based fluorescent light-up biosensor for label-free measurement of β-GT activity by utilizing 5-hmC glucosylation-initiated rolling circle transcription amplification (RCTA). We design a 5-hmC-modified multifunctional circular detection probe (5-hmC-MCDP) that integrates the functions of target-recognition, signal transduction, and transcription amplification in one probe. The introduction of β-GT catalyzes 5-hmC glucosylation of 5-hmC-MCDP probe, protecting the glucosylated 5-mC-MCDP probe from the cleavage by MspI. The remaining 5-hmC-MCDP probe can initiate RCTA reaction with the aid of T7 RNA polymerase, generating tandem Spinach RNA aptamers. The tandem Spinach RNA aptamers can be lightened up by fluorophore 3,5-difluoro-4-hydroxybenzylidene imidazolinone, facilitating label-free measurement of β-GT activity. Notably, the high specificity of MspI-catalyzed cleavage of nonglucosylated probe can efficiently inhibit nonspecific amplification, endowing this assay with a low background. Due to the higher efficiency of RCTA than the canonical promoter-initiated RNA synthesis, the signal-to-noise ratio of RCTA is 4.6-fold higher than that of linear template-based transcription amplification. This method is capable of sensitively detecting β-GT activity with a limit of detection of 2.03 × 10-5 U/mL, and it can be used for the screening of inhibitors and determination of kinetic parameters, with great potential in epigenetic research and drug discovery.
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Affiliation(s)
- Su Jiang
- College of Chemistry, Chemical Engineering and Materials Science, Shandong Normal University, Jinan, 250014, China
| | - Huanhuan Shi
- College of Chemistry, Chemical Engineering and Materials Science, Shandong Normal University, Jinan, 250014, China
| | - Qian Zhang
- College of Chemistry, Chemical Engineering and Materials Science, Shandong Normal University, Jinan, 250014, China
| | - Zi-Yue Wang
- College of Chemistry, Chemical Engineering and Materials Science, Shandong Normal University, Jinan, 250014, China.
| | - Yan Zhang
- College of Chemistry and Chemical Engineering, Qilu Normal University, Jinan, 250200, China.
| | - Chun-Yang Zhang
- College of Chemistry, Chemical Engineering and Materials Science, Shandong Normal University, Jinan, 250014, China; School of Chemistry and Chemical Engineering, Southeast University, Nanjing, 211189, China.
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5
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Sachan RK, Mistry V, Dholaria M, Rana A, Devgon I, Ali I, Iqbal J, Eldin SM, Mohammad Said Al-Tawaha AR, Bawazeer S, Dutta J, Karnwal A. Overcoming Mycobacterium tuberculosis Drug Resistance: Novel Medications and Repositioning Strategies. ACS OMEGA 2023; 8:32244-32257. [PMID: 37720746 PMCID: PMC10500578 DOI: 10.1021/acsomega.3c02563] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 08/10/2023] [Indexed: 09/19/2023]
Abstract
Mycobacterium tuberculosis, the bacterium responsible for tuberculosis, is a global health concern, affecting millions worldwide. This bacterium has earned a reputation as a formidable adversary due to its multidrug-resistant nature, allowing it to withstand many antibiotics. The development of this drug resistance in Mycobacterium tuberculosis is attributed to innate and acquired mechanisms. In the past, rifampin was considered a potent medication for treating tuberculosis infections. However, the rapid development of resistance to this drug by the bacterium underscores the pressing need for new therapeutic agents. Fortunately, several other medications previously overlooked for tuberculosis treatment are already available in the market. Moreover, several innovative drugs are under clinical investigation, offering hope for more effective treatments. To enhance the effectiveness of these drugs, it is recommended that researchers concentrate on identifying unique target sites within the bacterium during the drug development process. This strategy could potentially circumvent the issues presented by Mycobacterium drug resistance. This review primarily focuses on the characteristics of novel drug resistance mechanisms in Mycobacterium tuberculosis. It also discusses potential medications being repositioned or sourced from novel origins. The ultimate objective of this review is to discover efficacious treatments for tuberculosis that can successfully tackle the hurdles posed by Mycobacterium drug resistance.
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Affiliation(s)
| | - Vyoma Mistry
- C.
G. Bhakta Institute of Biotechnology, Uka
Tarsadia University, Bardoli 394350, Surat, India
| | - Mayuri Dholaria
- Naran
Lala College of Professional and Applied Sciences, Navsari 396450, Gujarat, India
| | - Abhishek Rana
- Jindal
Global Law School, OP Jindal Global University, Sonepat 131001, Haryana, India
| | - Inderpal Devgon
- Lovely
Professional University, Phagwara 144411, Punjab, India
| | - Iftikhar Ali
- Center
for Plant Science and Biodiversity, University
of Swat, Charbagh 19120, Pakistan
- Department
of Genetics and Development, Columbia University
Irving Medical Center, New York, New York 10032, United States
| | - Javed Iqbal
- Department
of Botany, Bacha Khan University, Charsadda, 24420 Khyber Pakhtunkhwa, Pakistan
| | - Sayed M. Eldin
- Center
of Research, Faculty of Engineering, Future
University in Egypt, New Cairo 11835, Egypt
| | | | - Sami Bawazeer
- Faculty
of Pharmacy, Department of Pharmacognosy, Umm Al-Qura University, Makkah 4041-4152, Kingdom of Saudi Arabia
| | - Joydeep Dutta
- Lovely
Professional University, Phagwara 144411, Punjab, India
| | - Arun Karnwal
- Lovely
Professional University, Phagwara 144411, Punjab, India
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6
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Chen WA, Li HY, Sayyad A, Huang CY, Cheng WC. Synthesis of Nitrone-derived Pyrrolidine Scaffolds and Their Combinatorial Libraries to Develop Selective α-l-Rhamnosidase Inhibitors. Chem Asian J 2022; 17:e202200172. [PMID: 35535638 DOI: 10.1002/asia.202200172] [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: 02/23/2022] [Revised: 04/28/2022] [Indexed: 11/06/2022]
Abstract
A general and flexible approach toward the development of α-l-rhamnosidase (α-l-Rha-ase) inhibitors is described. Five enantiopure poly-substituted pyrrolidine-based scaffolds bearing the C1-aminomethyl moiety were designed and synthesized from five-membered cyclic nitrones. Each structurally diversified amide library of these scaffolds was rapidly generated via combinatorial parallel synthesis and applied for in-situ inhibition study against α-l-Rha-ase, allowing us to efficiently identify new inhibition hits. Surprisingly, all promising inhibitors are derived from the same scaffold 3. Among them, the most potent and selective inhibitor is pyrrolidine 19 with Ki =0.24 μM, approximately 24-fold more potent than the reference compound DAA (Ki =5.7 μM). It is the first study to comprehensively prepare pyrrolidine-based scaffolds and libraries for inhibition study against α-l-Rha-ase.
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Affiliation(s)
- Wei-An Chen
- Genomics Research Centre, Academia Sinica, 128, Section 2, Academia Road, 11529, Taipei, Taiwan
| | - Huang-Yi Li
- Genomics Research Centre, Academia Sinica, 128, Section 2, Academia Road, 11529, Taipei, Taiwan
| | - Ashik Sayyad
- Genomics Research Centre, Academia Sinica, 128, Section 2, Academia Road, 11529, Taipei, Taiwan
| | - Chun-Yen Huang
- Genomics Research Centre, Academia Sinica, 128, Section 2, Academia Road, 11529, Taipei, Taiwan
| | - Wei-Chieh Cheng
- Genomics Research Centre, Academia Sinica, 128, Section 2, Academia Road, 11529, Taipei, Taiwan
- Department of Chemistry, National Cheng-Kung University, 1, University Road, 701, Tainan, Taiwan
- Department of Applied Chemistry, National Chiayi University, 300, Xuefu Rd., East Dist., 600, Chiayi, Taiwan
- Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, 100 Shih-Chuan 1st Rd., 807, Kaohsiung, Taiwan
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7
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Liu H, Gui X, Chen S, Fu W, Li X, Xiao T, Hou J, Jiang T. Structural Variability of Lipoarabinomannan Modulates Innate Immune Responses within Infected Alveolar Epithelial Cells. Cells 2022; 11:cells11030361. [PMID: 35159170 PMCID: PMC8834380 DOI: 10.3390/cells11030361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 01/15/2022] [Accepted: 01/18/2022] [Indexed: 02/04/2023] Open
Abstract
Mycobacterium tuberculosis (M. tb) is an intracellular pathogen persisting in phagosomes that has the ability to escape host immune surveillance causing tuberculosis (TB). Lipoarabinomannan (LAM), as a glycolipid, is one of the complex outermost components of the mycobacterial cell envelope and plays a critical role in modulating host responses during M. tb infection. Different species within the Mycobacterium genus exhibit distinct LAM structures and elicit diverse innate immune responses. However, little is known about the mechanisms. In this study, we first constructed a LAM-truncated mutant with fewer arabinofuranose (Araf) residues named M. sm-ΔM_6387 (Mycobacterium smegmatis arabinosyltransferase EmbC gene knockout strain). It exhibited some prominent cell wall defects, including tardiness of mycobacterial migration, loss of acid-fast staining, and increased cell wall permeability. Within alveolar epithelial cells (A549) infected by M. sm-ΔM_6387, the uptake rate was lower, phagosomes with bacterial degradation appeared, and microtubule-associated protein light chain 3 (LC3) recruitment was enhanced compared to wild type Mycobacterium smegmatis (M. smegmatis). We further confirmed that the variability in the removal capability of M. sm-ΔM_6387 resulted from host cell responses rather than the changes in the mycobacterial cell envelope. Moreover, we found that M. sm-ΔM_6387 or its glycolipid extracts significantly induced expression changes in some genes related to innate immune responses, including Toll-like receptor 2 (TLR2), class A scavenger receptor (SR-A), Rubicon, LC3, tumor necrosis factor alpha (TNF-α), Bcl-2, and Bax. Therefore, our studies suggest that nonpathogenic M. smegmatis can deposit LC3 on phagosomal membranes, and the decrease in the quantity of Araf residues for LAM molecules not only impacts mycobacterial cell wall integrity but also enhances host defense responses against the intracellular pathogens and decreases phagocytosis of host cells.
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Affiliation(s)
- Hanrui Liu
- Department of Biotechnology, The College of Basic Medical Science, Dalian Medical University, Dalian 116044, China; (H.L.); (X.G.); (W.F.); (X.L.); (T.X.); (J.H.)
| | - Xuwen Gui
- Department of Biotechnology, The College of Basic Medical Science, Dalian Medical University, Dalian 116044, China; (H.L.); (X.G.); (W.F.); (X.L.); (T.X.); (J.H.)
| | - Shixing Chen
- Key Laboratory of Science and Technology on Microsystem, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China;
| | - Weizhe Fu
- Department of Biotechnology, The College of Basic Medical Science, Dalian Medical University, Dalian 116044, China; (H.L.); (X.G.); (W.F.); (X.L.); (T.X.); (J.H.)
| | - Xiang Li
- Department of Biotechnology, The College of Basic Medical Science, Dalian Medical University, Dalian 116044, China; (H.L.); (X.G.); (W.F.); (X.L.); (T.X.); (J.H.)
| | - Tingyuan Xiao
- Department of Biotechnology, The College of Basic Medical Science, Dalian Medical University, Dalian 116044, China; (H.L.); (X.G.); (W.F.); (X.L.); (T.X.); (J.H.)
| | - Jie Hou
- Department of Biotechnology, The College of Basic Medical Science, Dalian Medical University, Dalian 116044, China; (H.L.); (X.G.); (W.F.); (X.L.); (T.X.); (J.H.)
| | - Tao Jiang
- Department of Biotechnology, The College of Basic Medical Science, Dalian Medical University, Dalian 116044, China; (H.L.); (X.G.); (W.F.); (X.L.); (T.X.); (J.H.)
- Correspondence: ; Tel.: +86-411-8611-0350
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Pereira G, Ghosh P, Santos A. A Bridging Centrality Plugin for GEPHI and a Case Study for Mycobacterium Tuberculosis H37Rv. IEEE/ACM TRANSACTIONS ON COMPUTATIONAL BIOLOGY AND BIOINFORMATICS 2021; 18:2741-2746. [PMID: 34665737 DOI: 10.1109/tcbb.2021.3120937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Bridging Centrality (BriCe) is a popular measure that combines the Betweenness centrality and Bridging coefficient metrics to characterize nodes acting as a bridge among clusters. However, there were no implementations of the BriCe plugin that can be readily used in the GEPHI software or any other software dedicated to graph-based studies. In this paper, we present the BriCe plugin for GEPHI. It is available as a third-party functionality from the native GEPHI interface as a handy plugin to add; hence, no additional download and installation process is necessary. The BriCe plugin for GEPHI is open-source, and one can access the code through the GEPHI GitHub repository. As a use case of the BriCe plugin, we analyzed the genome of Mycobacterium tuberculosis H37Rv to identify biological explanations on why some proteins were ranked with top BriCe values? For instance, we were able to formulate a new hypothesis combining the predicted sub cellular localization and high BriCe values concerning lipopolysaccharides (LPS) exportation. Our hypothesis provides a possible link among proteins of a glycosyltransferase group and the type VII Secretion System. The Bridging Centrality plugin for GEPHI is an easy to use tool for analyzing complex graphs and draw novel insights from graphical data.
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Abstract
Iminosugars are naturally occurring carbohydrate analogues known since 1967. These natural compounds and hundreds of their synthetic derivatives prepared over five decades have been mainly exploited to inhibit the glycosidases, the enzymes catalysing the glycosidic bond cleavage, in order to find new drugs for the treatment of type 2 diabetes and other diseases. However, iminosugars are also inhibitors of glycosyltransferases, the enzymes responsible for the synthesis of oligosaccharides and glycoconjugates. The selective inhibition of specific glycosyltransferases involved in cancer or bacterial infections could lead to innovative therapeutic agents. The synthesis and biological properties of all the iminosugars assayed to date as glycosyltransferase inhibitors are reviewed in the present article.
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Affiliation(s)
- Irene Conforti
- Institut des Biomolécules Max Mousseron (IBMM), UMR 5247, CNRS, Université de Montpellier, Ecole Nationale Supérieure de Chimie de Montpellier, 8 Rue de l'Ecole Normale, 34296 Montpellier cedex 5, France.
| | - Alberto Marra
- Institut des Biomolécules Max Mousseron (IBMM), UMR 5247, CNRS, Université de Montpellier, Ecole Nationale Supérieure de Chimie de Montpellier, 8 Rue de l'Ecole Normale, 34296 Montpellier cedex 5, France.
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10
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An ABC transporter Wzm-Wzt catalyzes translocation of lipid-linked galactan across the plasma membrane in mycobacteria. Proc Natl Acad Sci U S A 2021; 118:2023663118. [PMID: 33879617 DOI: 10.1073/pnas.2023663118] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Mycobacterium tuberculosis, one of the deadliest pathogens in human history, is distinguished by a unique, multilayered cell wall, which offers the bacterium a high level of protection from the attacks of the host immune system. The primary structure of the cell wall core, composed of covalently linked peptidoglycan, branched heteropolysaccharide arabinogalactan, and mycolic acids, is well known, and numerous enzymes involved in the biosynthesis of its components are characterized. The cell wall biogenesis takes place at both cytoplasmic and periplasmic faces of the plasma membrane, and only recently some of the specific transport systems translocating the metabolic intermediates between these two compartments have been characterized [M. Jackson, C. M. Stevens, L. Zhang, H. I. Zgurskaya, M. Niederweis, Chem. Rev., 10.1021/acs.chemrev.0c00869 (2020)]. In this work, we use CRISPR interference methodology in Mycobacterium smegmatis to functionally characterize an ATP-binding cassette (ABC) transporter involved in the translocation of galactan precursors across the plasma membrane. We show that genetic knockdown of the transmembrane subunit of the transporter results in severe morphological changes and the accumulation of an aberrantly long galactan precursor. Based on similarities with structures and functions of specific O-antigen ABC transporters of gram-negative bacteria [C. Whitfield, D. M. Williams, S. D. Kelly, J. Biol. Chem. 295, 10593-10609 (2020)], we propose a model for coupled synthesis and export of the galactan polymer precursor in mycobacteria.
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11
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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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12
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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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13
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Shahbaaz M, Potemkin V, Bisetty K, Hassan MI, Hussien MA. Classification and functional analyses of putative virulence factors of Mycobacterium tuberculosis: A combined sequence and structure based study. Comput Biol Chem 2020; 87:107270. [PMID: 32438116 DOI: 10.1016/j.compbiolchem.2020.107270] [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: 09/06/2019] [Revised: 04/16/2020] [Accepted: 04/26/2020] [Indexed: 11/17/2022]
Abstract
The emergence of the drug-resistant mechanisms in Mycobacterium tuberculosis poses the biggest challenges to the current therapeutic measures, which necessitates the identification of new drug targets. The Hypothetical Proteins (HPs), a class of functionally uncharacterized proteins, may provide a new class of undiscovered therapeutic targets. The genome of M. tuberculosis contains 1000 HPs with their sequences were analyzed using a variety of bioinformatics tools and the functional annotations were performed. The functions of 662 HPs were successfully predicted and further classified 483 HPs as enzymes, 141 HPs were predicted to be involved in the diverse cellular mechanisms and 38 HPs may function as transporters and carriers proteins. Furthermore, 28 HPs were predicted to be virulent in nature. Amongst them, the HP P95201, HP P9WM79, HP I6WZ30, HP I6 × 9T8, HP P9WKP3, and HP P9WK89 showed the highest virulence scores. Therefore, these proteins were subjected to extensive structure analyses and dynamics of their conformations were investigated using the principles of molecular dynamics simulations, each for a 150 ns time scale. This study provides a deeper understanding of the undiscovered drug targets and the generated outputs will facilitate the process of drug design and discovery against the infection of M. tuberculosis.
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Affiliation(s)
- Mohd Shahbaaz
- South African Medical Research Council Bioinformatics Unit, South African National Bioinformatics Institute (SANBI), University of the Western Cape, Private Bag X17, Bellville 7535, Cape Town, South Africa; Laboratory of Computational Modeling of Drugs, South Ural State University, 76 Lenin prospekt, 454080 Chelyabinsk, Russia
| | - Vladimir Potemkin
- Laboratory of Computational Modeling of Drugs, South Ural State University, 76 Lenin prospekt, 454080 Chelyabinsk, Russia
| | - Krishna Bisetty
- Department of Chemistry, Durban University of Technology, Durban, 4000, South Africa
| | - Md Imtaiyaz Hassan
- Center for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, Jamia Nagar, New Delhi, 110025, India
| | - Mostafa A Hussien
- Department of Chemistry, Faculty of Science, King Abdulaziz University, P.O. Box 80203 Jeddah 21589, Saudi Arabia; Department of Chemistry, Faculty of Science, Port Said University, Port Said, 42521, Egypt
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14
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Cryo-EM snapshots of mycobacterial arabinosyltransferase complex EmbB 2-AcpM 2. Protein Cell 2020; 11:505-517. [PMID: 32363534 PMCID: PMC7305291 DOI: 10.1007/s13238-020-00726-6] [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] [Received: 11/12/2019] [Accepted: 11/27/2019] [Indexed: 01/26/2023] Open
Abstract
Inhibition of Mycobacterium tuberculosis (Mtb) cell wall assembly is an established strategy for anti-TB chemotherapy. Arabinosyltransferase EmbB, which catalyzes the transfer of arabinose from the donor decaprenyl-phosphate-arabinose (DPA) to its arabinosyl acceptor is an essential enzyme for Mtb cell wall synthesis. Analysis of drug resistance mutations suggests that EmbB is the main target of the front-line anti-TB drug, ethambutol. Herein, we report the cryo-EM structures of Mycobacterium smegmatis EmbB in its “resting state” and DPA-bound “active state”. EmbB is a fifteen-transmembrane-spanning protein, assembled as a dimer. Each protomer has an associated acyl-carrier-protein (AcpM) on their cytoplasmic surface. Conformational changes upon DPA binding indicate an asymmetric movement within the EmbB dimer during catalysis. Functional studies have identified critical residues in substrate recognition and catalysis, and demonstrated that ethambutol inhibits transferase activity of EmbB by competing with DPA. The structures represent the first step directed towards a rational approach for anti-TB drug discovery.
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15
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Zhang L, Zhao Y, Gao Y, Wu L, Gao R, Zhang Q, Wang Y, Wu C, Wu F, Gurcha SS, Veerapen N, Batt SM, Zhao W, Qin L, Yang X, Wang M, Zhu Y, Zhang B, Bi L, Zhang X, Yang H, Guddat LW, Xu W, Wang Q, Li J, Besra GS, Rao Z. Structures of cell wall arabinosyltransferases with the anti-tuberculosis drug ethambutol. Science 2020; 368:1211-1219. [PMID: 32327601 DOI: 10.1126/science.aba9102] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 02/06/2020] [Accepted: 04/14/2020] [Indexed: 11/02/2022]
Abstract
The arabinosyltransferases EmbA, EmbB, and EmbC are involved in Mycobacterium tuberculosis cell wall synthesis and are recognized as targets for the anti-tuberculosis drug ethambutol. In this study, we determined cryo-electron microscopy and x-ray crystal structures of mycobacterial EmbA-EmbB and EmbC-EmbC complexes in the presence of their glycosyl donor and acceptor substrates and with ethambutol. These structures show how the donor and acceptor substrates bind in the active site and how ethambutol inhibits arabinosyltransferases by binding to the same site as both substrates in EmbB and EmbC. Most drug-resistant mutations are located near the ethambutol binding site. Collectively, our work provides a structural basis for understanding the biochemical function and inhibition of arabinosyltransferases and the development of new anti-tuberculosis agents.
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Affiliation(s)
- Lu Zhang
- Shanghai Institute for Advanced Immunochemical Studies, iHuman Institute, School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China.,State Key Laboratory of Medicinal Chemical Biology, Frontiers Science Center for Cell Response, College of Life Sciences, College of Pharmacy, Nankai University, Tianjin 300353, China
| | - Yao Zhao
- Shanghai Institute for Advanced Immunochemical Studies, iHuman Institute, School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China.,CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai 200031, China.,University of Chinese Academy of Sciences, Beijing 100101, China
| | - Yan Gao
- Laboratory of Structural Biology, Tsinghua University, Beijing 100084, China
| | - Lijie Wu
- Shanghai Institute for Advanced Immunochemical Studies, iHuman Institute, School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Ruogu Gao
- University of Chinese Academy of Sciences, Beijing 100101, China.,National Laboratory of Biomacromolecules and Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, CAS, Beijing 100101, China
| | - Qi Zhang
- Shanghai Institute for Advanced Immunochemical Studies, iHuman Institute, School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Yinan Wang
- Shanghai Institute for Advanced Immunochemical Studies, iHuman Institute, School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China.,University of Chinese Academy of Sciences, Beijing 100101, China
| | - Chengyao Wu
- Shanghai Institute for Advanced Immunochemical Studies, iHuman Institute, School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Fangyu Wu
- State Key Laboratory of Medicinal Chemical Biology, Frontiers Science Center for Cell Response, College of Life Sciences, College of Pharmacy, Nankai University, Tianjin 300353, China
| | - Sudagar S Gurcha
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Natacha Veerapen
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Sarah M Batt
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Wei Zhao
- State Key Laboratory of Medicinal Chemical Biology, Frontiers Science Center for Cell Response, College of Life Sciences, College of Pharmacy, Nankai University, Tianjin 300353, China
| | - Ling Qin
- Shanghai Institute for Advanced Immunochemical Studies, iHuman Institute, School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Xiuna Yang
- Shanghai Institute for Advanced Immunochemical Studies, iHuman Institute, School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Manfu Wang
- Shanghai Institute for Advanced Immunochemical Studies, iHuman Institute, School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Yan Zhu
- Shanghai Institute for Advanced Immunochemical Studies, iHuman Institute, School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Bing Zhang
- Shanghai Institute for Advanced Immunochemical Studies, iHuman Institute, School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Lijun Bi
- National Laboratory of Biomacromolecules and Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, CAS, Beijing 100101, China
| | - Xian'en Zhang
- National Laboratory of Biomacromolecules and Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, CAS, Beijing 100101, China
| | - Haitao Yang
- Shanghai Institute for Advanced Immunochemical Studies, iHuman Institute, School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Luke W Guddat
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Wenqing Xu
- Shanghai Institute for Advanced Immunochemical Studies, iHuman Institute, School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Quan Wang
- Shanghai Institute for Advanced Immunochemical Studies, iHuman Institute, School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China. .,National Laboratory of Biomacromolecules and Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, CAS, Beijing 100101, China
| | - Jun Li
- Shanghai Institute for Advanced Immunochemical Studies, iHuman Institute, School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China.
| | - Gurdyal S Besra
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
| | - Zihe Rao
- Shanghai Institute for Advanced Immunochemical Studies, iHuman Institute, School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China. .,State Key Laboratory of Medicinal Chemical Biology, Frontiers Science Center for Cell Response, College of Life Sciences, College of Pharmacy, Nankai University, Tianjin 300353, China.,Laboratory of Structural Biology, Tsinghua University, Beijing 100084, China.,National Laboratory of Biomacromolecules and Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, CAS, Beijing 100101, China
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16
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Wang L, Guo Z. An extensive review of studies on mycobacterium cell wall polysaccharide-related oligosaccharides – part I: Synthetic studies on arabinofuranosyl oligosaccharides. J Carbohydr Chem 2019. [DOI: 10.1080/07328303.2019.1630839] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Lizhen Wang
- Biology Institute, Qilu University of Technology (Shandong Academy of Sciences), Ji'nan, China
| | - Zhongwu Guo
- Department of Chemistry, University of Florida, Gainesville, FL, USA
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17
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Chakraborty P, Kumar A. The extracellular matrix of mycobacterial biofilms: could we shorten the treatment of mycobacterial infections? MICROBIAL CELL 2019; 6:105-122. [PMID: 30740456 PMCID: PMC6364259 DOI: 10.15698/mic2019.02.667] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A number of non-tuberculous mycobacterium species are opportunistic pathogens and ubiquitously form biofilms. These infections are often recalcitrant to treatment and require therapy with multiple drugs for long duration. The biofilm resident bacteria also display phenotypic drug tolerance and thus it has been hypothesized that the drug unresponsiveness in vivo could be due to formation of biofilms inside the host. We have discussed the biofilms of several pathogenic non-tuberculous mycobacterium (NTM) species in context to the in vivo pathologies. Besides pathogenic NTMs, Mycobacterium smegmatis is often used as a model organism for understanding mycobacterial physiology and has been studied extensively for understanding the mycobacterial biofilms. A number of components of the mycobacterial cell wall such as glycopeptidolipids, short chain mycolic acids, monomeromycolyl diacylglycerol, etc. have been shown to play an important role in formation of pellicle biofilms. It shall be noted that these components impart a hydrophobic character to the mycobacterial cell surface that facilitates cell to cell interaction. However, these components are not necessarily the constituents of the extracellular matrix of mycobacterial biofilms. In the end, we have described the biofilms of Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis. Three models of Mtb biofilm formation have been proposed to study the factors regulating biofilm formation, the physiology of the resident bacteria, and the nature of the biomaterial that holds these bacterial masses together. These models include pellicle biofilms formed at the liquid-air interface of cultures, leukocyte lysate-induced biofilms, and thiol reductive stressinduced biofilms. All the three models offer their own advantages in the study of Mtb biofilms. Interestingly, lipids (mainly keto-mycolic acids) are proposed to be the primary component of extracellular polymeric substance (EPS) in the pellicle biofilm, whereas the leukocyte lysate-induced and thiol reductive stress-induced biofilms possess polysaccharides as the primary component of EPS. Both models also contain extracellular DNA in the EPS. Interestingly, thiol reductive stressinduced Mtb biofilms are held together by cellulose and yet unidentified structural proteins. We believe that a better understanding of the EPS of Mtb biofilms and the physiology of the resident bacteria will facilitate the development of shorter regimen for TB treatment.
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Affiliation(s)
- Poushali Chakraborty
- Council of Scientific and Industrial Research, Institute of Microbial Technology, Chandigarh, India 160036
| | - Ashwani Kumar
- Council of Scientific and Industrial Research, Institute of Microbial Technology, Chandigarh, India 160036.,CSIR-Academy of Scientific & Innovative Research (AcSIR), Council of Scientific & Industrial Research, New Delhi-110001
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18
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Kolbe K, Veleti SK, Reiling N, Lindhorst TK. Lectins of Mycobacterium tuberculosis - rarely studied proteins. Beilstein J Org Chem 2019; 15:1-15. [PMID: 30680034 PMCID: PMC6334816 DOI: 10.3762/bjoc.15.1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Accepted: 11/29/2018] [Indexed: 12/19/2022] Open
Abstract
The importance of bacterial lectins for adhesion, pathogenicity, and biofilm formation is well established for many Gram-positive and Gram-negative bacteria. However, there is very little information available about lectins of the tuberculosis-causing bacterium, Mycobacterium tuberculosis (Mtb). In this paper we review previous studies on the carbohydrate-binding characteristics of mycobacteria and related Mtb proteins, discussing their potential relevance to Mtb infection and pathogenesis.
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Affiliation(s)
- Katharina Kolbe
- Tuberculosis Research Section, Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, 33 North Drive, Bethesda, 20892, MD, United States
| | - Sri Kumar Veleti
- Tuberculosis Research Section, Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, 33 North Drive, Bethesda, 20892, MD, United States
| | - Norbert Reiling
- Microbial Interface Biology, Research Center Borstel, Leibniz Lung Center, Parkallee 22, 23845 Borstel, Germany.,German Center for Infection Research (DZIF), Borstel Site, 23845 Borstel, Germany
| | - Thisbe K Lindhorst
- Otto Diels Institute of Organic Chemistry, Christiana Albertina University of Kiel, Otto-Hahn-Platz 3-4, 24118 Kiel, Germany
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19
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Micoli F, Costantino P, Adamo R. Potential targets for next generation antimicrobial glycoconjugate vaccines. FEMS Microbiol Rev 2018; 42:388-423. [PMID: 29547971 PMCID: PMC5995208 DOI: 10.1093/femsre/fuy011] [Citation(s) in RCA: 112] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 03/13/2018] [Indexed: 12/21/2022] Open
Abstract
Cell surface carbohydrates have been proven optimal targets for vaccine development. Conjugation of polysaccharides to a carrier protein triggers a T-cell-dependent immune response to the glycan moiety. Licensed glycoconjugate vaccines are produced by chemical conjugation of capsular polysaccharides to prevent meningitis caused by meningococcus, pneumococcus and Haemophilus influenzae type b. However, other classes of carbohydrates (O-antigens, exopolysaccharides, wall/teichoic acids) represent attractive targets for developing vaccines. Recent analysis from WHO/CHO underpins alarming concern toward antibiotic-resistant bacteria, such as the so called ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter spp.) and additional pathogens such as Clostridium difficile and Group A Streptococcus. Fungal infections are also becoming increasingly invasive for immunocompromised patients or hospitalized individuals. Other emergencies could derive from bacteria which spread during environmental calamities (Vibrio cholerae) or with potential as bioterrorism weapons (Burkholderia pseudomallei and mallei, Francisella tularensis). Vaccination could aid reducing the use of broad-spectrum antibiotics and provide protection by herd immunity also to individuals who are not vaccinated. This review analyzes structural and functional differences of the polysaccharides exposed on the surface of emerging pathogenic bacteria, combined with medical need and technological feasibility of corresponding glycoconjugate vaccines.
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Affiliation(s)
- Francesca Micoli
- GSK Vaccines Institute for Global Health (GVGH), Via Fiorentina 1, 53100 Siena
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20
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21
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Rismondo J, Percy MG, Gründling A. Discovery of genes required for lipoteichoic acid glycosylation predicts two distinct mechanisms for wall teichoic acid glycosylation. J Biol Chem 2018; 293:3293-3306. [PMID: 29343515 PMCID: PMC5836110 DOI: 10.1074/jbc.ra117.001614] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 01/13/2018] [Indexed: 12/20/2022] Open
Abstract
The bacterial cell wall is an important and highly complex structure that is essential for bacterial growth because it protects bacteria from cell lysis and environmental insults. A typical Gram-positive bacterial cell wall is composed of peptidoglycan and the secondary cell wall polymers, wall teichoic acid (WTA) and lipoteichoic acid (LTA). In many Gram-positive bacteria, LTA is a polyglycerol-phosphate chain that is decorated with d-alanine and sugar residues. However, the function of and proteins responsible for the glycosylation of LTA are either unknown or not well-characterized. Here, using bioinformatics, genetic, and NMR spectroscopy approaches, we found that the Bacillus subtilis csbB and yfhO genes are essential for LTA glycosylation. Interestingly, the Listeria monocytogenes gene lmo1079, which encodes a YfhO homolog, was not required for LTA glycosylation, but instead was essential for WTA glycosylation. LTA is polymerized on the outside of the cell and hence can only be glycosylated extracellularly. Based on the similarity of the genes coding for YfhO homologs that are required in B. subtilis for LTA glycosylation or in L. monocytogenes for WTA glycosylation, we hypothesize that WTA glycosylation might also occur extracellularly in Listeria species. Finally, we discovered that in L. monocytogenes, lmo0626 (gtlB) was required for LTA glycosylation, indicating that the encoded protein has a function similar to that of YfhO, although the proteins are not homologous. Together, our results enable us to propose an updated model for LTA glycosylation and also indicate that glycosylation of WTA might occur through two different mechanisms in Gram-positive bacteria.
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Affiliation(s)
- Jeanine Rismondo
- From the Section of Microbiology and Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, United Kingdom
| | - Matthew G Percy
- From the Section of Microbiology and Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, United Kingdom
| | - Angelika Gründling
- From the Section of Microbiology and Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, United Kingdom
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22
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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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23
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Giri A, Gupta S, Safi H, Narang A, Shrivastava K, Kumar Sharma N, Lingaraju S, Hanif M, Bhatnagar A, Menon B, Alland D, Varma-Basil M. Polymorphisms in Rv3806c (ubiA) and the upstream region of embA in relation to ethambutol resistance in clinical isolates of Mycobacterium tuberculosis from North India. Tuberculosis (Edinb) 2018. [DOI: 10.1016/j.tube.2017.10.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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24
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Kolbe K, Möckl L, Sohst V, Brandenburg J, Engel R, Malm S, Bräuchle C, Holst O, Lindhorst TK, Reiling N. Azido Pentoses: A New Tool To Efficiently Label Mycobacterium tuberculosis Clinical Isolates. Chembiochem 2017; 18:1172-1176. [PMID: 28249101 DOI: 10.1002/cbic.201600706] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2016] [Indexed: 01/27/2023]
Abstract
Mycobacterium tuberculosis (Mtb), the main causative agent of tuberculosis (Tb), has a complex cell envelope which forms an efficient barrier to antibiotics, thus contributing to the challenges of anti-tuberculosis therapy. However, the unique Mtb cell wall can be considered an advantage and be utilized to selectively label Mtb bacteria. Here we introduce three azido pentoses as new compounds for metabolic labeling of Mtb: 3-azido arabinose (3AraAz), 3-azido ribose (3RiboAz), and 5-azido arabinofuranose (5AraAz). 5AraAz demonstrated the highest level of Mtb labeling and was efficiently incorporated into the Mtb cell wall. All three azido pentoses can be easily used to label a variety of Mtb clinical isolates without influencing Mtb-dependent phagosomal maturation arrest in infection studies with human macrophages. Thus, this metabolic labeling method offers the opportunity to attach desired molecules to the surface of Mtb bacteria in order to facilitate investigation of the varying virulence characteristics of different Mtb clinical isolates, which influence the outcome of a Tb infection.
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Affiliation(s)
- Katharina Kolbe
- Otto Diels Institute of Organic Chemistry, Christiana Albertina University of Kiel, Otto-Hahn-Platz 3-4, 24118, Kiel, Germany
- Microbial Interface Biology, Research Center Borstel, Leibniz Center for Medicine and Biosciences, Parkallee 22, 23845, Borstel, Germany
- Present address: Tuberculosis Research Section, NIAID, NIH, 33 North Drive, Bethesda, MD, 20814, USA
| | - Leonhard Möckl
- Department of Physical Chemistry, Ludwig Maximilian University of Munich, Butenandstrasse 11, 81377, Munich, Germany
| | - Victoria Sohst
- Microbial Interface Biology, Research Center Borstel, Leibniz Center for Medicine and Biosciences, Parkallee 22, 23845, Borstel, Germany
| | - Julius Brandenburg
- Microbial Interface Biology, Research Center Borstel, Leibniz Center for Medicine and Biosciences, Parkallee 22, 23845, Borstel, Germany
| | - Regina Engel
- Structural Biochemistry, Research Center Borstel, Leibniz Center for Medicine and Biosciences, Parkallee 4, 23845, Borstel, Germany
| | - Sven Malm
- Molecular and Experimental Mycobacteriology, Research Center Borstel, Leibniz Center for Medicine and Biosciences, Parkallee 22, 23845, Borstel, Germany
| | - Christoph Bräuchle
- Department of Physical Chemistry, Ludwig Maximilian University of Munich, Butenandstrasse 11, 81377, Munich, Germany
| | - Otto Holst
- Structural Biochemistry, Research Center Borstel, Leibniz Center for Medicine and Biosciences, Parkallee 4, 23845, Borstel, Germany
| | - Thisbe K Lindhorst
- Otto Diels Institute of Organic Chemistry, Christiana Albertina University of Kiel, Otto-Hahn-Platz 3-4, 24118, Kiel, Germany
| | - Norbert Reiling
- Microbial Interface Biology, Research Center Borstel, Leibniz Center for Medicine and Biosciences, Parkallee 22, 23845, Borstel, Germany
- German Center for Infection Research (DZIF), Partner Site Hamburg-Lübeck-Borstel, Parkallee 1-40, 23845, Borstel, Germany
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Angala SK, McNeil MR, Shi L, Joe M, Pham H, Zuberogoitia S, Nigou J, Boot CM, Lowary TL, Gilleron M, Jackson M. Biosynthesis of the Methylthioxylose Capping Motif of Lipoarabinomannan in Mycobacterium tuberculosis. ACS Chem Biol 2017; 12:682-691. [PMID: 28075556 DOI: 10.1021/acschembio.6b01071] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Lipoarabinomannan (LAM) is a lipoglycan found in abundant quantities in the cell envelope of all mycobacteria. The nonreducing arabinan termini of LAM display species-specific structural microheterogeneity that impacts the biological activity of the entire molecule. Mycobacterium tuberculosis, for instance, produces mannoside caps made of one to three α-(1 → 2)-Manp-linked residues that may be further substituted with an α-(1 → 4)-linked methylthio-d-xylose (MTX) residue. While the biological functions and catalytic steps leading to the formation of the mannoside caps of M. tuberculosis LAM have been well established, the biosynthetic origin and biological relevance of the MTX motif remain elusive. We here report on the discovery of a five-gene cluster dedicated to the biosynthesis of the MTX capping motif of M. tuberculosis LAM, and on the functional characterization of two glycosyltransferases, MtxS and MtxT, responsible, respectively, for the production of decaprenyl-phospho-MTX (DP-MTX) and the transfer of MTX from DP-MTX to the mannoside caps of LAM. Collectively, our NMR spectroscopic and mass spectrometric analyses of mtxS and mtxT overexpressors and knockout mutants support a biosynthetic model wherein the conversion of 5'-methylthioadenosine, which is a ubiquitous byproduct of spermidine biosynthesis, into 5'-methylthioribose-1-phosphate precedes the formation of a 5'-methylthioribose nucleotide sugar, followed by the epimerization at C-3 of the ribose residue, and the transfer of MTX from the nucleotide sugar to decaprenyl-phosphate yielding the substrate for transfer onto LAM. The conservation of the MTX biosynthetic genes in a number of Actinomycetes suggests that this discrete glycosyl substituent may be more widespread in prokaryotes than originally thought.
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Affiliation(s)
- Shiva kumar Angala
- Mycobacteria
Research Laboratories, Department of Microbiology, Immunology and
Pathology, Colorado State University, Fort Collins, Colorado 80523-1682, United States
| | - Michael R. McNeil
- Mycobacteria
Research Laboratories, Department of Microbiology, Immunology and
Pathology, Colorado State University, Fort Collins, Colorado 80523-1682, United States
| | - Libin Shi
- Mycobacteria
Research Laboratories, Department of Microbiology, Immunology and
Pathology, Colorado State University, Fort Collins, Colorado 80523-1682, United States
| | - Maju Joe
- Alberta
Glycomics Centre and Department of Chemistry, The University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Ha Pham
- Mycobacteria
Research Laboratories, Department of Microbiology, Immunology and
Pathology, Colorado State University, Fort Collins, Colorado 80523-1682, United States
| | - Sophie Zuberogoitia
- Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, UPS, 205 route de Narbonne, F-31077 Toulouse, France
| | - Jérôme Nigou
- Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, UPS, 205 route de Narbonne, F-31077 Toulouse, France
| | - Claudia M. Boot
- Central
Instrumentation Facility, Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, United States
| | - Todd L. Lowary
- Alberta
Glycomics Centre and Department of Chemistry, The University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Martine Gilleron
- Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, UPS, 205 route de Narbonne, F-31077 Toulouse, France
| | - Mary Jackson
- Mycobacteria
Research Laboratories, Department of Microbiology, Immunology and
Pathology, Colorado State University, Fort Collins, Colorado 80523-1682, United States
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Nunes-Costa D, Maranha A, Costa M, Alarico S, Empadinhas N. Glucosylglycerate metabolism, bioversatility and mycobacterial survival. Glycobiology 2016; 27:213-227. [DOI: 10.1093/glycob/cww132] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Accepted: 12/14/2016] [Indexed: 12/17/2022] Open
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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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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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Janoš P, Trnka T, Kozmon S, Tvaroška I, Koča J. Different QM/MM Approaches To Elucidate Enzymatic Reactions: Case Study on ppGalNAcT2. J Chem Theory Comput 2016; 12:6062-6076. [PMID: 27787999 DOI: 10.1021/acs.jctc.6b00531] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Hybrid QM/MM computational studies can provide invaluable insight into the mechanisms of enzymatic reactions that can be exploited for rational drug design. Various approaches are available for such studies. However, their strengths and weaknesses may not be immediately apparent. Using the retaining glycosyltransferase ppGalNAcT2 as a case study, we compare different methodologies used to obtain reaction paths and transition state information. Ab Initio MD using CPMD coupled with the String Method is used to derive the minimum free energy reaction path. The geometrical features of the free energy path, especially around the transition state, agree with the minimum potential energy path obtained by the much less computationally expensive Nudged Elastic Band method. The barrier energy, however, differs by 8 kcal/mol. The free energy surface generated by metadynamics provides a rough overview of the reaction and can confirm the physical relevance of optimized paths or provide an initial guess for path optimization methods. Calculations of enzymatic reactions are usually performed at best at the DFT level of theory. A comparison of widely used functionals with high-level DLPNO-CCSD(T)/CBS data on the potential energy profile serves as a validation of the usability of DFT for this type of enzymatic reaction. The M06-2X meta-hybrid functional in particular matches the DLPNO-CCSD(T)/CBS reference extremely well with errors within 1 kcal/mol. However, even pure-GGA functional OPBE provides sufficient accuracy for this type of study.
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Affiliation(s)
| | | | - Stanislav Kozmon
- Institute of Chemistry, Slovak Academy of Sciences , 845 38 Bratislava, Slovak Republic
| | - Igor Tvaroška
- Institute of Chemistry, Slovak Academy of Sciences , 845 38 Bratislava, Slovak Republic
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30
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Mann E, Whitfield C. A widespread three-component mechanism for the periplasmic modification of bacterial glycoconjugates. CAN J CHEM 2016. [DOI: 10.1139/cjc-2015-0594] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The diverse structures of bacterial glycoconjugates are generally established during the early stages of synthesis by the activities of nucleotide sugar-dependent glycosyltransferases active in the cytoplasm. However, in some cases, further modifications of varying complexity occur after the glycoconjugate is exported to the periplasm. These processes are distinguished by the involvement of polyprenyl monosphosphoryl donors and require glycosyltransferases possessing GT-C folds. Established prototypes are found in modifications of some bacterial lipopolysaccharides, where 4-amino-4-deoxy-l-arabinose is added to lipid A and glucose side branches are used to modify O-antigens. Here we review the current understanding of these systems and describe similarities to other periplasmic glycan modifications in bacteria and the N-glycosylation pathway for assembly of eukaryotic glycoproteins.
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Affiliation(s)
- Evan Mann
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1G 2W1, Canada
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - Chris Whitfield
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1G 2W1, Canada
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1G 2W1, Canada
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Joe M, Lowary TL. Synthesis of a homologous series of galactofuranose-containing mycobacterial arabinogalactan fragments. CAN J CHEM 2016. [DOI: 10.1139/cjc-2016-0416] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Mycobacteria, including the human pathogen Mycobacterium tuberculosis, the causative agent of tuberculosis, produce a complex cell wall structure made of carbohydrates and lipids. The major structural element of the mycobacterial cell wall is a glycoconjugate called the mycolic acid – arabinogalactan – peptidoglycan (mAGP) complex. Inhibition of mAGP biosynthesis is a proven strategy for developing anti-mycobacterial drugs, and thus, understanding the pathways and enzymes involved in the assembly of this molecule is of interest. In this paper, we describe the chemical synthesis of a panel of nine oligosaccharide fragments (4–12) of the galactan domain of the mAGP complex designed as biosynthetic probes. These structures, ranging in size from a hexasaccharide to a tetradecasaccharide, are potential substrates for two biosynthetic enzymes, GlfT2 and AftA, and represent the largest mycobacterial galactan fragments synthesized to date. The route developed was iterative and provided multimilligram quantities of the target molecules 4–12 in good overall yield.
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Affiliation(s)
- Maju Joe
- Alberta Glycomics Centre and Department of Chemistry, The University of Alberta, Edmonton, AB T6G 2G2, Canada
- Alberta Glycomics Centre and Department of Chemistry, The University of Alberta, Edmonton, AB T6G 2G2, Canada
| | - Todd L. Lowary
- Alberta Glycomics Centre and Department of Chemistry, The University of Alberta, Edmonton, AB T6G 2G2, Canada
- Alberta Glycomics Centre and Department of Chemistry, The University of Alberta, Edmonton, AB T6G 2G2, Canada
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van Wyk N, Drancourt M, Henrissat B, Kremer L. Current perspectives on the families of glycoside hydrolases ofMycobacterium tuberculosis: their importance and prospects for assigning function to unknowns. Glycobiology 2016; 27:112-122. [DOI: 10.1093/glycob/cww099] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2016] [Revised: 08/28/2016] [Accepted: 09/26/2016] [Indexed: 11/14/2022] Open
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Frédéric CJM, Tikad A, Fu J, Pan W, Zheng RB, Koizumi A, Xue X, Lowary TL, Vincent SP. Synthesis of Unprecedented Sulfonylated Phosphono-exo-Glycals Designed as Inhibitors of the Three Mycobacterial Galactofuranose Processing Enzymes. Chemistry 2016; 22:15913-15920. [PMID: 27628709 DOI: 10.1002/chem.201603161] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Indexed: 11/06/2022]
Abstract
This study reports a new methodology to synthesize exo-glycals bearing both a sulfone and a phosphonate. This synthetic strategy provides a way to generate exo-glycals displaying two electron-withdrawing groups and was applied to eight different carbohydrates from the furanose and pyranose series. The Z/E configurations of these tetrasubstituted enol ethers could be ascertained using NMR spectroscopic techniques. Deprotection of an exo-glycal followed by an UMP (uridine monophosphate) coupling generated two new UDP (uridine diphosphate)-galactofuranose analogues. These two Z/E isomers were evaluated as inhibitors of UGM, GlfT1, and GlfT2, the three mycobacterial galactofuranose processing enzymes. Molecule 46-(E) is the first characterized inhibitor of GlfT1 reported to date and was also found to efficiently inhibit UGM in a reversible manner. Interestingly, GlfT2 showed a better affinity for the (Z) isomer. The three enzymes studied in the present work are not only interesting because, mechanistically, they are still the topic of intense investigations, but also because they constitute very important targets for the development of novel antimycobacterial agents.
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Affiliation(s)
- Christophe J-M Frédéric
- University of Namur (UNamur), Département de Chimie, Laboratoire de Chimie Bio-Organique, rue de Bruxelles 61, 5000, Namur, Belgium
| | - Abdellatif Tikad
- University of Namur (UNamur), Département de Chimie, Laboratoire de Chimie Bio-Organique, rue de Bruxelles 61, 5000, Namur, Belgium
| | - Jian Fu
- University of Namur (UNamur), Département de Chimie, Laboratoire de Chimie Bio-Organique, rue de Bruxelles 61, 5000, Namur, Belgium
| | - Weidong Pan
- The Key Laboratory of Chemistry for Natural Products of Guizhou Province, Chinese Academy of Sciences, 202, Sha-chong South Road, Guiyang, 550002, P. R. China
| | - Ruixiang B Zheng
- Department of Chemistry and Alberta Glycomics Centre, University of Alberta, Gunning-Lemieux Chemistry Centre, 11227 Saskatchewan Drive, Edmonton, AB T6G 2G2, Canada
| | - Akihiko Koizumi
- Department of Chemistry and Alberta Glycomics Centre, University of Alberta, Gunning-Lemieux Chemistry Centre, 11227 Saskatchewan Drive, Edmonton, AB T6G 2G2, Canada
| | - Xiaochao Xue
- Department of Chemistry and Alberta Glycomics Centre, University of Alberta, Gunning-Lemieux Chemistry Centre, 11227 Saskatchewan Drive, Edmonton, AB T6G 2G2, Canada
| | - Todd L Lowary
- Department of Chemistry and Alberta Glycomics Centre, University of Alberta, Gunning-Lemieux Chemistry Centre, 11227 Saskatchewan Drive, Edmonton, AB T6G 2G2, Canada
| | - Stéphane P Vincent
- University of Namur (UNamur), Département de Chimie, Laboratoire de Chimie Bio-Organique, rue de Bruxelles 61, 5000, Namur, Belgium.
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Poulin MB, Lowary TL. Chemical Insight into the Mechanism and Specificity of GlfT2, a Bifunctional Galactofuranosyltransferase from Mycobacteria. J Org Chem 2016; 81:8123-30. [PMID: 27557056 DOI: 10.1021/acs.joc.6b01501] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Mycobacteria, including the human pathogen Mycobacterium tuberculosis, produce a complex cell wall structure that is essential to survival. A key component of this structure is a glycoconjugate, the mycolyl-arabinogalactan-peptidoglycan complex, which has at its core a galactan domain composed of galactofuranose (Galf) residues linked to peptidoglycan. Because galactan biosynthesis is essential for mycobacterial viability, compounds that interfere with this process are potential therapeutic agents for treating mycobacterial diseases, including tuberculosis. Galactan biosynthesis in mycobacteria involves two glycosyltransferases, GlfT1 and GlfT2, which have been the subject of increasing interest in recent years. This Synopsis summarizes efforts to characterize the mechanism and specificity of GlfT2, which is responsible for introducing the majority of the Galf residues into mycobacterial galactan.
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Affiliation(s)
- Myles B Poulin
- Alberta Glycomics Centre and Department of Chemistry, University of Alberta , 11227 Saskatchewan Drive, Edmonton, Alberta T6G 2G2, Canada
| | - Todd L Lowary
- Alberta Glycomics Centre and Department of Chemistry, University of Alberta , 11227 Saskatchewan Drive, Edmonton, Alberta T6G 2G2, Canada
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35
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Mitachi K, Siricilla S, Yang D, Kong Y, Skorupinska-Tudek K, Swiezewska E, Franzblau SG, Kurosu M. Fluorescence-based assay for polyprenyl phosphate-GlcNAc-1-phosphate transferase (WecA) and identification of novel antimycobacterial WecA inhibitors. Anal Biochem 2016; 512:78-90. [PMID: 27530653 DOI: 10.1016/j.ab.2016.08.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Revised: 07/18/2016] [Accepted: 08/08/2016] [Indexed: 11/26/2022]
Abstract
Polyprenyl phosphate-GlcNAc-1-phosphate transferase (WecA) is an essential enzyme for the growth of Mycobacterium tuberculosis (Mtb) and some other bacteria. Mtb WecA catalyzes the transformation from UDP-GlcNAc to decaprenyl-P-P-GlcNAc, the first membrane-anchored glycophospholipid that is responsible for the biosynthesis of mycolylarabinogalactan in Mtb. Inhibition of WecA will block the entire biosynthesis of essential cell wall components of Mtb in both replicating and non-replicating states, making this enzyme a target for development of novel drugs. Here, we report a fluorescence-based method for the assay of WecA using a modified UDP-GlcNAc, UDP-Glucosamine-C6-FITC (1), a membrane fraction prepared from an M. smegmatis strain, and the E. coli B21WecA. Under the optimized conditions, UDP-Glucosamine-C6-FITC (1) can be converted to the corresponding decaprenyl-P-P-Glucosamine-C6-FITC (3) in 61.5% yield. Decaprenyl-P-P-Glucosamine-C6-FITC is readily extracted with n-butanol and can be quantified by ultraviolet-visible (UV-vis) spectrometry. Screening of the compound libraries designed for bacterial phosphotransferases resulted in the discovery of a selective WecA inhibitor, UT-01320 (12) that kills both replicating and non-replicating Mtb at low concentration. UT-01320 (12) also kills the intracellular Mtb in macrophages. We conclude that the WecA assay reported here is amenable to medium- and high-throughput screening, thus facilitating the discovery of novel WecA inhibitors.
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Affiliation(s)
- Katsuhiko Mitachi
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, 881 Madison Avenue, Memphis, TN 38163-0001, United States
| | - Shajila Siricilla
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, 881 Madison Avenue, Memphis, TN 38163-0001, United States
| | - Dong Yang
- Department of Microbiology, Immunology & Biochemistry, University of Tennessee Health Science Center, 858 Madison Avenue, Memphis, TN 38163-0001, United Sates
| | - Ying Kong
- Department of Microbiology, Immunology & Biochemistry, University of Tennessee Health Science Center, 858 Madison Avenue, Memphis, TN 38163-0001, United Sates
| | - Karolina Skorupinska-Tudek
- Department of Lipid Biochemistry, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5a, 02-106 Warszawa, Poland
| | - Ewa Swiezewska
- Department of Lipid Biochemistry, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5a, 02-106 Warszawa, Poland
| | - Scott G Franzblau
- Institute for Tuberculosis Research, College of Pharmacy, University of Illinois at Chicago, 833 S. Wood Street, Chicago, IL 60612, United States
| | - Michio Kurosu
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, 881 Madison Avenue, Memphis, TN 38163-0001, United States.
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Synthesis and Evaluation of Bicyclo[3.1.0]hexane-Based UDP-Galf Analogues as Inhibitors of the Mycobacterial Galactofuranosyltransferase GlfT2. Molecules 2016; 21:molecules21081053. [PMID: 27529206 PMCID: PMC6272867 DOI: 10.3390/molecules21081053] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 08/05/2016] [Accepted: 08/06/2016] [Indexed: 11/17/2022] Open
Abstract
UDP-galactofuranose (UDP-Galf) is the donor substrate for both bifunctional galactofuranosyltransferases, GlfT1 and GlfT2, which are involved in the biosynthesis of mycobacterial galactan. In this paper, a group of UDP-Galf mimics were synthesized via reductive amination of a bicyclo[3.1.0]hexane-based amine by reacting with aromatic, linear, or uridine-containing aldehydes. These compounds were evaluated against GlfT2 using a coupled spectrophotometric assay, and were shown to be weak inhibitors of the enzyme.
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Identification of a Lipoteichoic Acid Glycosyltransferase Enzyme Reveals that GW-Domain-Containing Proteins Can Be Retained in the Cell Wall of Listeria monocytogenes in the Absence of Lipoteichoic Acid or Its Modifications. J Bacteriol 2016; 198:2029-42. [PMID: 27185829 PMCID: PMC4944223 DOI: 10.1128/jb.00116-16] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 05/10/2016] [Indexed: 12/04/2022] Open
Abstract
Listeria monocytogenes is a foodborne Gram-positive bacterial pathogen, and many of its virulence factors are either secreted proteins or proteins covalently or noncovalently attached to the cell wall. Previous work has indicated that noncovalently attached proteins with GW (glycine-tryptophan) domains are retained in the cell wall by binding to the cell wall polymer lipoteichoic acid (LTA). LTA is a glycerol phosphate polymer, which is modified in L. monocytogenes with galactose and d-alanine residues. We identified Lmo0933 as the cytoplasmic glycosyltransferase required for the LTA glycosylation process and renamed the protein GtlA, for glycosyltransferase LTA A. Using L. monocytogenes mutants lacking galactose or d-alanine modifications or the complete LTA polymer, we show that GW domain proteins are retained within the cell wall, indicating that other cell wall polymers are involved in the retention of GW domain proteins. Further experiments revealed peptidoglycan as the binding receptor as a purified GW domain fusion protein can bind to L. monocytogenes cells lacking wall teichoic acid (WTA) as well as purified peptidoglycan derived from a wild-type or WTA-negative strain. With this, we not only identify the first enzyme involved in the LTA glycosylation process, but we also provide new insight into the binding mechanism of noncovalently attached cell wall proteins.
IMPORTANCE Over the past 20 years, a large number of bacterial genome sequences have become available. Computational approaches are used for the genome annotation and identification of genes and encoded proteins. However, the function of many proteins is still unknown and often cannot be predicted bioinformatically. Here, we show that the previously uncharacterized Listeria monocytogenes gene lmo0933 likely codes for a glycosyltransferase required for the decoration of the cell wall polymer lipoteichoic acid (LTA) with galactose residues. Using L. monocytogenes mutants lacking LTA modifications or the complete polymer, we show that specific cell wall proteins, often associated with virulence, are retained within the cell wall, indicating that additional cell wall polymers are involved in their retention.
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Thiol reductive stress induces cellulose-anchored biofilm formation in Mycobacterium tuberculosis. Nat Commun 2016; 7:11392. [PMID: 27109928 PMCID: PMC4848537 DOI: 10.1038/ncomms11392] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 03/21/2016] [Indexed: 12/30/2022] Open
Abstract
Mycobacterium tuberculosis (Mtb) forms biofilms harbouring antibiotic-tolerant bacilli in vitro, but the factors that induce biofilm formation and the nature of the extracellular material that holds the cells together are poorly understood. Here we show that intracellular thiol reductive stress (TRS) induces formation of Mtb biofilms in vitro, which harbour drug-tolerant but metabolically active bacteria with unchanged levels of ATP/ADP, NAD(+)/NADH and NADP(+)/NADPH. The development of these biofilms requires DNA, RNA and protein synthesis. Transcriptional analysis suggests that Mtb modulates only ∼7% of its genes for survival in biofilms. In addition to proteins, lipids and DNA, the extracellular material in these biofilms is primarily composed of polysaccharides, with cellulose being a key component. Our results contribute to a better understanding of the mechanisms underlying Mtb biofilm formation, although the clinical relevance of Mtb biofilms in human tuberculosis remains unclear.
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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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Chlubnová I, Králová B, Dvořáková H, Spiwok V, Filipp D, Nugier-Chauvin C, Daniellou R, Ferrières V. Biocatalyzed synthesis of difuranosides and their ability to trigger production of TNF-α. Bioorg Med Chem Lett 2016; 26:1550-1553. [PMID: 26876932 DOI: 10.1016/j.bmcl.2016.02.018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 02/05/2016] [Accepted: 02/07/2016] [Indexed: 10/22/2022]
Abstract
Transglycosylation reactions biocatalyzed by the native arabinofuranosidase Araf51 and using d-galactosyl, d-fucosyl and 6-deoxy-6-fluoro-D-galactosyl derivatives as donors and acceptors provided di-to pentahexofuranosides. The immunostimulatory potency of these compounds, and more especially their ability to induce production of TNF-α, was evaluated on the murine macrophage cell line, Raw 264.7. The results obtained showed concentration-dependent and most importantly, structure-dependent responses. Interestingly, oligoarabinofuranosides belonging to the oligopentafuranoside family displayed concentration-, chain length and aglycon-dependent bioactivities irrespective of their fine chemical variations. Thus, neo-oligofuranosides in D-Galf series, as well as their D-Fucf and 6-fluorinated counterparts are indeed potential sources of immunostimulating agents.
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Affiliation(s)
- Ilona Chlubnová
- Ecole Nationale Supérieure de Chimie de Rennes, CNRS, UMR 6226, 11 Allée de Beaulieu, CS 50837, 35708 Rennes Cedex 7, France; Université européenne de Bretagne, France; Department of Biochemistry and Microbiology, Institute of Chemical Technology of Prague, Techniká 3, 166 28 Prague 6, Czech Republic; Laboratory of Immunobiology, Institute of Molecular Genetics AS CR, Videnska 1083, 142 20 Prague 4, Czech Republic
| | - Blanka Králová
- Ecole Nationale Supérieure de Chimie de Rennes, CNRS, UMR 6226, 11 Allée de Beaulieu, CS 50837, 35708 Rennes Cedex 7, France; Department of Biochemistry and Microbiology, Institute of Chemical Technology of Prague, Techniká 3, 166 28 Prague 6, Czech Republic
| | - Hana Dvořáková
- Department of Biochemistry and Microbiology, Institute of Chemical Technology of Prague, Techniká 3, 166 28 Prague 6, Czech Republic; Laboratory of NMR Spectroscopy, Institute of Chemical Technology of Prague, Techniká 5, 166 28 Prague 6, Czech Republic
| | - Vojtěch Spiwok
- Department of Biochemistry and Microbiology, Institute of Chemical Technology of Prague, Techniká 3, 166 28 Prague 6, Czech Republic
| | - Dominik Filipp
- Laboratory of Immunobiology, Institute of Molecular Genetics AS CR, Videnska 1083, 142 20 Prague 4, Czech Republic
| | - Caroline Nugier-Chauvin
- Ecole Nationale Supérieure de Chimie de Rennes, CNRS, UMR 6226, 11 Allée de Beaulieu, CS 50837, 35708 Rennes Cedex 7, France; Université européenne de Bretagne, France
| | - Richard Daniellou
- Ecole Nationale Supérieure de Chimie de Rennes, CNRS, UMR 6226, 11 Allée de Beaulieu, CS 50837, 35708 Rennes Cedex 7, France; Université européenne de Bretagne, France
| | - Vincent Ferrières
- Ecole Nationale Supérieure de Chimie de Rennes, CNRS, UMR 6226, 11 Allée de Beaulieu, CS 50837, 35708 Rennes Cedex 7, France; Université européenne de Bretagne, France.
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Sahloul K, Lowary TL. Development of an Orthogonal Protection Strategy for the Synthesis of Mycobacterial Arabinomannan Fragments. J Org Chem 2015; 80:11417-34. [DOI: 10.1021/acs.joc.5b02083] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- Kamar Sahloul
- Alberta
Glycomics Centre
and Department of Chemistry, University of Alberta, Edmonton, AB, T6G 2G2, Canada
| | - Todd L. Lowary
- Alberta
Glycomics Centre
and Department of Chemistry, University of Alberta, Edmonton, AB, T6G 2G2, Canada
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42
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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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43
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The chemoselective O-glycosylation of alcohols in the presence of a phosphate diester and its application to the synthesis of oligomannosylated phosphatidyl inositols. Tetrahedron 2015. [DOI: 10.1016/j.tet.2015.06.041] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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44
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Larrouy-Maumus G, Gilleron M, Skovierová H, Zuberogoitia S, Brennan PJ, Puzo G, Jackson M, Nigou J. A glycomic approach reveals a new mycobacterial polysaccharide. Glycobiology 2015; 25:1163-71. [PMID: 26261090 DOI: 10.1093/glycob/cwv061] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Accepted: 08/05/2015] [Indexed: 12/26/2022] Open
Abstract
Mycobacterium tuberculosis lipoarabinomannan (LAM) and biosynthetically related lipoglycans and glycans play an important role in host-pathogen interactions. Therefore, the elucidation of the complete biosynthetic pathways of these important molecules is expected to afford novel therapeutic targets. The characterization of biosynthetic enzymes and transporters involved in the formation and localization of these complex macromolecules in the bacterial cell envelope largely relies on genetic manipulation of mycobacteria and subsequent analyses of lipoglycan structural alterations. However, lipoglycans are present in relatively low amounts. Their purification to homogeneity remains tedious and time-consuming. To overcome these issues and to reduce the biomass and time required for lipoglycan purification, we report here the development of a methodology to efficiently purify lipoglycans by sodium deoxycholate-polyacrylamide gel electrophoresis. This faster purification method can be applied on a small amount of mycobacterial cells biomass (10-50 mg), resulting in tens of micrograms of purified lipoglycans. This amount of purified products was found to be sufficient to undertake structural analyses of lipoglycans and glycans carbohydrate domains by a combination of highly sensitive analytical procedures, involving cryoprobe NMR analysis of intact macromolecules and chemical degradations monitored by gas chromatography and capillary electrophoresis. This glycomic approach was successfully applied to the purification and structural characterization of a newly identified polysaccharide, structurally related to LAM, in the model fast-growing species Mycobacterium smegmatis.
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Affiliation(s)
- Gérald Larrouy-Maumus
- CNRS, Institut de Pharmacologie et de Biologie Structurale (IPBS), UMR 5089 CNRS/Université Paul Sabatier, 205 route de Narbonne, BP 64182, F-31077 Toulouse Cedex 4, France Université de Toulouse, Université Paul Sabatier, IPBS, F-31077 Toulouse, France
| | - Martine Gilleron
- CNRS, Institut de Pharmacologie et de Biologie Structurale (IPBS), UMR 5089 CNRS/Université Paul Sabatier, 205 route de Narbonne, BP 64182, F-31077 Toulouse Cedex 4, France Université de Toulouse, Université Paul Sabatier, IPBS, F-31077 Toulouse, France
| | - Henrieta Skovierová
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523-1682, USA
| | - Sophie Zuberogoitia
- CNRS, Institut de Pharmacologie et de Biologie Structurale (IPBS), UMR 5089 CNRS/Université Paul Sabatier, 205 route de Narbonne, BP 64182, F-31077 Toulouse Cedex 4, France Université de Toulouse, Université Paul Sabatier, IPBS, F-31077 Toulouse, France
| | - Patrick J Brennan
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523-1682, USA
| | - Germain Puzo
- CNRS, Institut de Pharmacologie et de Biologie Structurale (IPBS), UMR 5089 CNRS/Université Paul Sabatier, 205 route de Narbonne, BP 64182, F-31077 Toulouse Cedex 4, France Université de Toulouse, Université Paul Sabatier, IPBS, F-31077 Toulouse, France
| | - Mary Jackson
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523-1682, USA
| | - Jérôme Nigou
- CNRS, Institut de Pharmacologie et de Biologie Structurale (IPBS), UMR 5089 CNRS/Université Paul Sabatier, 205 route de Narbonne, BP 64182, F-31077 Toulouse Cedex 4, France Université de Toulouse, Université Paul Sabatier, IPBS, F-31077 Toulouse, France
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45
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Wu MC, Styles MQ, Law BJC, Struck AW, Nunns L, Micklefield J. Engineered biosynthesis of enduracidin lipoglycopeptide antibiotics using the ramoplanin mannosyltransferase Ram29. MICROBIOLOGY-SGM 2015; 161:1338-47. [PMID: 25878261 PMCID: PMC4635501 DOI: 10.1099/mic.0.000095] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The lipopeptides ramoplanin from Actinoplanes sp. ATCC 33076 and enduracidin produced by Streptomyces fungicidicus are effective antibiotics against a number of drug-resistant Gram-positive pathogens. While these two antibiotics share a similar cyclic peptide structure, comprising 17 amino acids with an N-terminal fatty acid side chain, ramoplanin has a di-mannose moiety that enduracidin lacks. The mannosyl substituents of ramoplanin enhance aqueous solubility, which was important in the development of ramoplanin as a potential treatment for Clostridium difficile infections. In this study we have determined the function of the putative mannosyltransferase encoded by ram29 from the ramoplanin biosynthetic gene cluster. Bioinformatics revealed that Ram29 is an integral membrane protein with a putative DxD motif that is suggested to bind to, and activate, a polyprenyl phosphomannose donor and an extracytoplasmic C-terminal domain that is predicted to bind the ramoplanin aglycone acceptor. The ram29 gene was cloned into the tetracycline inducible plasmid pMS17 and integrated into the genome of the enduracidin producer S. fungicidicus. Induction of ram29 expression in S. fungicidicus resulted in the production of monomannosylated enduracidin derivatives, which are not present in the WT strain. Tandem MS analysis showed that mannosylation occurs on the Hpg11 residue of enduracidin. In addition to confirming the function of Ram29, these findings demonstrate how the less common, membrane-associated, polyprenyl phosphosugar-dependent glycosyltransferases can be used in natural product glycodiversification. Such a strategy may be valuable in future biosynthetic engineering approaches aimed at improving the physico-chemical and biological properties of bioactive secondary metabolites including antibiotics.
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Affiliation(s)
- Ming-Cheng Wu
- School of Chemistry and Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester M1 7DN, UK
| | - Matthew Q Styles
- School of Chemistry and Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester M1 7DN, UK
| | - Brian J C Law
- School of Chemistry and Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester M1 7DN, UK
| | - Anna-Winona Struck
- School of Chemistry and Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester M1 7DN, UK
| | - Laura Nunns
- School of Chemistry and Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester M1 7DN, UK
| | - Jason Micklefield
- School of Chemistry and Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester M1 7DN, UK
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46
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Eppe G, El Bkassiny S, Vincent SP. Galactofuranose Biosynthesis: Discovery, Mechanisms and Therapeutic Relevance. CARBOHYDRATES IN DRUG DESIGN AND DISCOVERY 2015. [DOI: 10.1039/9781849739993-00209] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Galactofuranose, the atypical and thermodynamically disfavored form of d-galactose, has in reality a very old history in chemistry and biochemistry. The purpose of this book chapter is to give an overview on the fundamental aspects of the galactofuranose biosynthesis, from the biological occurrence to the search of inhibitors.
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Affiliation(s)
- Guillaume Eppe
- University of Namur, Département de Chimie, Laboratoire de Chimie Bio-Organique rue de Bruxelles 61 B-5000 Namur Belgium
| | - Sandy El Bkassiny
- University of Namur, Département de Chimie, Laboratoire de Chimie Bio-Organique rue de Bruxelles 61 B-5000 Namur Belgium
| | - Stéphane P. Vincent
- University of Namur, Département de Chimie, Laboratoire de Chimie Bio-Organique rue de Bruxelles 61 B-5000 Namur Belgium
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47
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Sohlenkamp C, Geiger O. Bacterial membrane lipids: diversity in structures and pathways. FEMS Microbiol Rev 2015; 40:133-59. [DOI: 10.1093/femsre/fuv008] [Citation(s) in RCA: 571] [Impact Index Per Article: 63.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/05/2015] [Indexed: 12/22/2022] Open
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48
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Alderwick LJ, Harrison J, Lloyd GS, Birch HL. The Mycobacterial Cell Wall--Peptidoglycan and Arabinogalactan. Cold Spring Harb Perspect Med 2015; 5:a021113. [PMID: 25818664 DOI: 10.1101/cshperspect.a021113] [Citation(s) in RCA: 129] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The mycobacterial bacillus is encompassed by a remarkably elaborate cell wall structure. The mycolyl-arabinogalactan-peptidoglycan (mAGP) complex is essential for the viability of Mycobacterium tuberculosis and maintains a robust basal structure supporting the upper "myco-membrane." M. tuberculosis peptidoglycan, although appearing to be unexceptional at first glance, contains a number of unique molecular subtleties that become particularly important as the TB-bacilli enters into nonreplicative growth during dormancy. Arabinogalactan, a highly branched polysaccharide, serves to connect peptidoglycan with the outer mycolic acid layer, and a variety of unique glycolsyltransferases are used for its assembly. In this review, we shall explore the microbial chemistry of this unique heteropolysacchride, examine the molecular genetics that underpins its fabrication, and discuss how the essential biosynthetic process might be exploited for the development of future anti-TB chemotherapies.
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Affiliation(s)
- Luke J Alderwick
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham B15 2TT, United Kingdom
| | - James Harrison
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham B15 2TT, United Kingdom
| | - Georgina S Lloyd
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham B15 2TT, United Kingdom
| | - Helen L Birch
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham B15 2TT, United Kingdom
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49
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Kügler JH, Le Roes-Hill M, Syldatk C, Hausmann R. Surfactants tailored by the class Actinobacteria. Front Microbiol 2015; 6:212. [PMID: 25852670 PMCID: PMC4365757 DOI: 10.3389/fmicb.2015.00212] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Accepted: 03/02/2015] [Indexed: 12/20/2022] Open
Abstract
Globally the change towards the establishment of a bio-based economy has resulted in an increased need for bio-based applications. This, in turn, has served as a driving force for the discovery and application of novel biosurfactants. The class Actinobacteria represents a vast group of microorganisms with the ability to produce a diverse range of secondary metabolites, including surfactants. Understanding the extensive nature of the biosurfactants produced by actinobacterial strains can assist in finding novel biosurfactants with new potential applications. This review therefore presents a comprehensive overview of the knowledge available on actinobacterial surfactants, the chemical structures that have been completely or partly elucidated, as well as the identity of the biosurfactant-producing strains. Producer strains of not yet elucidated compounds are discussed, as well as the original habitats of all the producer strains, which seems to indicate that biosurfactant production is environmentally driven. Methodology applied in the isolation, purification and structural elucidation of the different types of surface active compounds, as well as surfactant activity tests, are also discussed. Overall, actinobacterial surfactants can be summarized to include the dominantly occurring trehalose-comprising surfactants, other non-trehalose containing glycolipids, lipopeptides and the more rare actinobacterial surfactants. The lack of structural information on a large proportion of actinobacterial surfactants should be considered as a driving force to further explore the abundance and diversity of these compounds. This would allow for a better understanding of actinobacterial surface active compounds and their potential for biotechnological application.
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Affiliation(s)
- Johannes H. Kügler
- Technical Biology, Institute of Process Engineering in Life Sciences, Karlsruhe Institute of TechnologyKarlsruhe, Germany
| | - Marilize Le Roes-Hill
- Biocatalysis and Technical Biology Research Group, Institute of Biomedical and Microbial Biotechnology, Cape Peninsula University of TechnologyBellville, South Africa
| | - Christoph Syldatk
- Technical Biology, Institute of Process Engineering in Life Sciences, Karlsruhe Institute of TechnologyKarlsruhe, Germany
| | - Rudolf Hausmann
- Bioprocess Engineering, Institute of Food Science and Biotechnology, University of HohenheimStuttgart, Germany
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50
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Shukla S, Richardson ET, Athman JJ, Shi L, Wearsch PA, McDonald D, Banaei N, Boom WH, Jackson M, Harding CV. Mycobacterium tuberculosis lipoprotein LprG binds lipoarabinomannan and determines its cell envelope localization to control phagolysosomal fusion. PLoS Pathog 2014; 10:e1004471. [PMID: 25356793 PMCID: PMC4214796 DOI: 10.1371/journal.ppat.1004471] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Accepted: 09/14/2014] [Indexed: 01/17/2023] Open
Abstract
Mycobacterium tuberculosis (Mtb) virulence is decreased by genetic deletion of the lipoprotein LprG, but the function of LprG remains unclear. We report that LprG expressed in Mtb binds to lipoglycans, such as lipoarabinomannan (LAM), that mediate Mtb immune evasion. Lipoglycan binding to LprG was dependent on both insertion of lipoglycan acyl chains into a hydrophobic pocket on LprG and a novel contribution of lipoglycan polysaccharide components outside of this pocket. An lprG null mutant (Mtb ΔlprG) had lower levels of surface-exposed LAM, revealing a novel role for LprG in determining the distribution of components in the Mtb cell envelope. Furthermore, this mutant failed to inhibit phagosome-lysosome fusion, an immune evasion strategy mediated by LAM. We propose that LprG binding to LAM facilitates its transfer from the plasma membrane into the cell envelope, increasing surface-exposed LAM, enhancing cell envelope integrity, allowing inhibition of phagosome-lysosome fusion and enhancing Mtb survival in macrophages. The causative agent of tuberculosis, Mycobacterium tuberculosis (Mtb), persists in phagosomes inside infected macrophages. Mtb expresses lipoarabinomannan (LAM), which inhibits fusion of phagosomes with lysosomes as a means for Mtb to evade host defense. LAM is present in the cell envelope, which surrounds Mtb and interfaces with the host, but its localization remains unclear. We show that LprG, an Mtb lipoprotein, binds LAM and controls its distribution in the cell envelope. A mutant strain of Mtb that lacks LprG has less LAM at the surface of the cell envelope. This decreases LAM-mediated inhibition of phagosome-lysosome fusion, thereby impairing an immune evasion mechanism. We propose that LprG facilitates transfer of LAM from the plasma membrane into the cell envelope, enhancing its interaction with the host and ability to regulate host defense. Our results reveal mechanisms that determine bacterial cell envelope function and influence host-pathogen interactions and pathogen evasion of host defense.
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Affiliation(s)
- Supriya Shukla
- Department of Pathology, Case Western Reserve University/University Hospitals Case Medical Center, Cleveland, Ohio, United States of America
| | - Edward T. Richardson
- Department of Pathology, Case Western Reserve University/University Hospitals Case Medical Center, Cleveland, Ohio, United States of America
| | - Jaffre J. Athman
- Department of Pathology, Case Western Reserve University/University Hospitals Case Medical Center, Cleveland, Ohio, United States of America
| | - Libin Shi
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Pamela A. Wearsch
- Department of Pathology, Case Western Reserve University/University Hospitals Case Medical Center, Cleveland, Ohio, United States of America
| | - David McDonald
- Center for AIDS Research, Case Western Reserve University/University Hospitals Case Medical Center, Cleveland, Ohio, United States of America
- Department of Molecular Biology and Microbiology, Case Western Reserve University/University Hospitals Case Medical Center, Cleveland, Ohio, United States of America
| | - Niaz Banaei
- Department of Pathology, Stanford University School of Medicine, Palo Alto, California, United States of America
| | - W. Henry Boom
- Department of Pathology, Case Western Reserve University/University Hospitals Case Medical Center, Cleveland, Ohio, United States of America
- Center for AIDS Research, Case Western Reserve University/University Hospitals Case Medical Center, Cleveland, Ohio, United States of America
- Division of Infectious Diseases, Case Western Reserve University/University Hospitals Case Medical Center, Cleveland, Ohio, United States of America
| | - Mary Jackson
- Department of Pathology, Stanford University School of Medicine, Palo Alto, California, United States of America
| | - Clifford V. Harding
- Department of Pathology, Case Western Reserve University/University Hospitals Case Medical Center, Cleveland, Ohio, United States of America
- Center for AIDS Research, Case Western Reserve University/University Hospitals Case Medical Center, Cleveland, Ohio, United States of America
- Division of Infectious Diseases, Case Western Reserve University/University Hospitals Case Medical Center, Cleveland, Ohio, United States of America
- * E-mail:
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