1
|
Angala SK, Joe M, McNeil MR, Liav A, Lowary TL, Jackson M. Use of Synthetic Glycolipids to Probe the Number and Position of Arabinan Chains on Mycobacterial Arabinogalactan. ACS Chem Biol 2021; 16:20-26. [PMID: 33382235 PMCID: PMC7859836 DOI: 10.1021/acschembio.0c00765] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The arabinogalactan of Corynebacterianeae is a critical heteropolysaccharide that tethers outer membrane mycolic acids to peptidoglycan thus forming the characteristic cell wall core of these prokaryotes. An essential α-(1→5)-arabinosyltransferase, AftA, is responsible for the transfer of the first arabinofuranosyl (Araf) unit of the arabinan domain to the galactan backbone of arabinogalactan, but the number and precise position at which Araf residue(s) is/are added in mycobacteria remain ill-defined. Using membrane preparations from Mycobacterium smegmatis overexpressing aftA, farnesyl-phospho-arabinose as an Araf donor, and a series of synthetic galactan acceptors of various lengths, we here show that a single priming arabinosyl residue substitutes the C-5 position of a precisely positioned internal 6-linked galactofuranosyl residue of the galactan acceptors, irrespective of their length. This unexpected result suggests that, like the structurally related mycobacterial lipoarabinomannans, the arabinogalactan of mycobacteria may in fact harbor a single arabinan chain.
Collapse
Affiliation(s)
- Shiva Kumar Angala
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523-1682, USA
| | - Maju Joe
- Department of Chemistry, The University of Alberta, Edmonton, AB, T6G 2G2, Canada
| | - Michael R. McNeil
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523-1682, USA
| | - Avraham Liav
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523-1682, USA
| | - Todd L. Lowary
- Department of Chemistry, The University of Alberta, Edmonton, AB, T6G 2G2, Canada
- Institute of Biological Chemistry, Academia Sinica, Nangang Taipei 11529, Taiwan
| | - Mary Jackson
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523-1682, USA
| |
Collapse
|
2
|
Abstract
Extracellular polysaccharides and glycoproteins of pathogenic bacteria assist in adherence, autoaggregation, biofilm formation, and host immune system evasion. As a result, considerable research in the field of glycobiology is dedicated to study the composition and function of glycans associated with virulence, as well as the enzymes involved in their biosynthesis with the aim to identify novel antibiotic targets. Especially, insights into the enzyme mechanism, substrate binding, and transition-state structures are valuable as a starting point for rational inhibitor design. An intriguing aspect of enzymes that generate or process polysaccharides and glycoproteins is the level of processivity. The existence of enzymatic processivity reflects the need for regulation of the final glycan/glycoprotein length and structure, depending on the role they perform. In this Review, we describe the currently reported examples of various processive enzymes involved in polymerization and transfer of sugar moieties, predominantly in bacterial pathogens, with a focus on the biochemical methods, to showcase the importance of studying processivity for understanding the mechanism.
Collapse
Affiliation(s)
- Liubov Yakovlieva
- Stratingh Institute for Chemistry, University of Groningen, 9747 AG Groningen, The Netherlands
| | - Marthe T. C. Walvoort
- Stratingh Institute for Chemistry, University of Groningen, 9747 AG Groningen, The Netherlands
| |
Collapse
|
3
|
Biosynthesis of Galactan in Mycobacterium tuberculosis as a Viable TB Drug Target? Antibiotics (Basel) 2020; 9:antibiotics9010020. [PMID: 31935842 PMCID: PMC7168186 DOI: 10.3390/antibiotics9010020] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 12/27/2019] [Accepted: 01/02/2020] [Indexed: 12/21/2022] Open
Abstract
While target-based drug design has proved successful in several therapeutic areas, this approach has not yet provided compelling outcomes in the field of antibacterial agents. This statement remains especially true for the development of novel therapeutic interventions against tuberculosis, an infectious disease that is among the top ten leading causes of death globally. Mycobacterial galactan is an important component of the protective cell wall core of the tuberculosis pathogen and it could provide a promising target for the design of new drugs. In this review, we summarize the current knowledge on galactan biosynthesis in Mycobacterium tuberculosis, including landmark findings that led to the discovery and understanding of three key enzymes in this pathway: UDP-galactose mutase, and galactofuranosyl transferases GlfT1 and GlfT2. Moreover, we recapitulate the efforts aimed at their inhibition. The predicted common transition states of the three enzymes provide the lucrative possibility of multitargeting in pharmaceutical development, a favourable property in the mitigation of drug resistance. We believe that a tight interplay between target-based computational approaches and experimental methods will result in the development of original inhibitors that could serve as the basis of a new generation of drugs against tuberculosis.
Collapse
|
4
|
Olagnon C, Monjaras Feria J, Grünwald-Gruber C, Blaukopf M, Valvano MA, Kosma P. Synthetic Phosphodiester-Linked 4-Amino-4-deoxy-l-arabinose Derivatives Demonstrate that ArnT is an Inverting Aminoarabinosyl Transferase. Chembiochem 2019; 20:2936-2948. [PMID: 31233657 PMCID: PMC6902282 DOI: 10.1002/cbic.201900349] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Indexed: 12/22/2022]
Abstract
4‐Amino‐4‐deoxy‐l‐arabinopyranose (Ara4N) residues have been linked to antibiotic resistance due to reduction of the negative charge in the lipid A and core regions of the bacterial lipopolysaccharide (LPS). To study the enzymatic transfer of Ara4N onto lipid A, which is catalysed by the ArnT transferase, we chemically synthesised a series of anomeric phosphodiester‐linked lipid Ara4N derivatives containing linear aliphatic chains as well as E‐ and Z‐configured monoterpene units. Coupling reactions were based on sugar‐derived H‐phosphonates, followed by oxidation and global deprotection. The enzymatic Ara4N transfer was performed in vitro with crude membranes from a deep‐rough mutant from Escherichia coli as acceptor. Product formation was detected by TLC and LC‐ESI‐QTOF mass spectrometry. Out of seven analogues tested, only the α‐neryl derivative was accepted by the Burkholderia cenocepacia ArnT protein, leading to substitution of the Kdo2‐lipid A acceptor and thus affording evidence that ArnT is an inverting glycosyl transferase that requires the Z‐configured double bond next to the anomeric phosphate moiety. This approach provides an easily accessible donor substrate for biochemical studies relating to modifications of bacterial LPS that modulate antibiotic resistance and immune recognition.
Collapse
Affiliation(s)
- Charlotte Olagnon
- Department of Chemistry, University of Natural Resources and Life Sciences-Vienna, Muthgasse 18, 1190, Vienna, Austria
| | - Julia Monjaras Feria
- Wellcome-Wolfson Institute of Experimental Medicine, Queen's University Belfast, 97 Lisburn Road, BT9 7BL, Belfast, UK
| | - Clemens Grünwald-Gruber
- Department of Chemistry, University of Natural Resources and Life Sciences-Vienna, Muthgasse 18, 1190, Vienna, Austria
| | - Markus Blaukopf
- Department of Chemistry, University of Natural Resources and Life Sciences-Vienna, Muthgasse 18, 1190, Vienna, Austria
| | - Miguel A Valvano
- Wellcome-Wolfson Institute of Experimental Medicine, Queen's University Belfast, 97 Lisburn Road, BT9 7BL, Belfast, UK
| | - Paul Kosma
- Department of Chemistry, University of Natural Resources and Life Sciences-Vienna, Muthgasse 18, 1190, Vienna, Austria
| |
Collapse
|
5
|
Calabretta PJ, Hodges HL, Kraft MB, Marando VM, Kiessling LL. Bacterial Cell Wall Modification with a Glycolipid Substrate. J Am Chem Soc 2019; 141:9262-9272. [PMID: 31081628 DOI: 10.1021/jacs.9b02290] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Despite the ubiquity and importance of glycans in biology, methods to probe their structures in cells are limited. Mammalian glycans can be modulated using metabolic incorporation, a process in which non-natural sugars are taken up by cells, converted to nucleotide-sugar intermediates, and incorporated into glycans via biosynthetic pathways. These studies have revealed that glycan intermediates can be shunted through multiple pathways, and this complexity can be heightened in bacteria, as they can catabolize diverse glycans. We sought to develop a strategy that probes structures recalcitrant to metabolic incorporation and that complements approaches focused on nucleotide sugars. We reasoned that lipid-linked glycans, which are intermediates directly used in glycan biosynthesis, would offer an alternative. We generated synthetic arabinofuranosyl phospholipids to test this strategy in Corynebacterium glutamicum and Mycobacterium smegmatis, organisms that serve as models of Mycobacterium tuberculosis. Using a C. glutamicum mutant that lacks arabinan, we identified synthetic glycosyl donors whose addition restores cell wall arabinan, demonstrating that non-natural glycolipids can serve as biosynthetic intermediates and function in chemical complementation. The addition of an isotopically labeled glycan substrate facilitated cell wall characterization by NMR. Structural analysis revealed that all five known arabinofuranosyl transferases could process the exogenous lipid-linked sugar donor, allowing for the full recovery of the cell envelope. The lipid-based probe could also rescue wild-type cells treated with an inhibitor of cell wall biosynthesis. Our data indicate that surrogates of natural lipid-linked glycans can intervene in the cell's traditional workflow, indicating that biosynthetic incorporation is a powerful strategy for probing glycan structure and function.
Collapse
Affiliation(s)
- Phillip J Calabretta
- Department of Chemistry , Massachusetts Institute of Technology , Cambridge , Massachusetts 02139 , United States
| | | | | | - Victoria M Marando
- Department of Chemistry , Massachusetts Institute of Technology , Cambridge , Massachusetts 02139 , United States
| | - Laura L Kiessling
- Department of Chemistry , Massachusetts Institute of Technology , Cambridge , Massachusetts 02139 , United States
| |
Collapse
|
6
|
Wang X, Krasnova L, Wu KB, Wu WS, Cheng TJ, Wong CH. Towards new antibiotics targeting bacterial transglycosylase: Synthesis of a Lipid II analog as stable transition-state mimic inhibitor. Bioorg Med Chem Lett 2018; 28:2708-2712. [PMID: 29602680 PMCID: PMC6182773 DOI: 10.1016/j.bmcl.2018.03.035] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 03/12/2018] [Accepted: 03/13/2018] [Indexed: 10/17/2022]
Abstract
Described here is the asymmetric synthesis of iminosugar 2b, a Lipid II analog, designed to mimic the transition state of transglycosylation catalyzed by the bacterial transglycosylase. The high density of functional groups, together with a rich stereochemistry, represents an extraordinary challenge for chemical synthesis. The key 2,6-anti- stereochemistry of the iminosugar ring was established through an iridium-catalyzed asymmetric allylic amination. The developed synthetic route is suitable for the synthesis of focused libraries to enable the structure-activity relationship study and late-stage modification of iminosugar scaffold with variable lipid, peptide and sugar substituents. Compound 2b showed 70% inhibition of transglycosylase from Acinetobacter baumannii, providing a basis for further improvement.
Collapse
Affiliation(s)
- Xiaolei Wang
- The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA 92122, USA
| | - Larissa Krasnova
- The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA 92122, USA
| | - Kevin Binchia Wu
- The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA 92122, USA
| | - Wei-Shen Wu
- Genomics Research Center, Academia Sinica, 128 Sec 2 Academia Road, Taipei, Nankang 115, Taiwan
| | - Ting-Jen Cheng
- Genomics Research Center, Academia Sinica, 128 Sec 2 Academia Road, Taipei, Nankang 115, Taiwan
| | - Chi-Huey Wong
- The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA 92122, USA; Genomics Research Center, Academia Sinica, 128 Sec 2 Academia Road, Taipei, Nankang 115, Taiwan.
| |
Collapse
|
7
|
Harvey DJ. Analysis of carbohydrates and glycoconjugates by matrix-assisted laser desorption/ionization mass spectrometry: An update for 2013-2014. MASS SPECTROMETRY REVIEWS 2018; 37:353-491. [PMID: 29687922 DOI: 10.1002/mas.21530] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Accepted: 11/29/2016] [Indexed: 06/08/2023]
Abstract
This review is the eighth update of the original article published in 1999 on the application of Matrix-assisted laser desorption/ionization mass spectrometry (MALDI) mass spectrometry to the analysis of carbohydrates and glycoconjugates and brings coverage of the literature to the end of 2014. Topics covered in the first part of the review include general aspects such as theory of the MALDI process, matrices, derivatization, MALDI imaging, fragmentation, and arrays. The second part of the review is devoted to applications to various structural types such as oligo- and poly- saccharides, glycoproteins, glycolipids, glycosides, and biopharmaceuticals. Much of this material is presented in tabular form. The third part of the review covers medical and industrial applications of the technique, studies of enzyme reactions, and applications to chemical synthesis. © 2018 Wiley Periodicals, Inc. Mass Spec Rev 37:353-491, 2018.
Collapse
Affiliation(s)
- David J Harvey
- Target Discovery Institute, Nuffield Department of Medicine, University of Oxford, Roosevelt Drive, Oxford, OX3 7FZ, United Kingdom
| |
Collapse
|
8
|
Xue X, Zheng RB, Koizumi A, Han L, Klassen JS, Lowary TL. Synthetic polyprenol-pyrophosphate linked oligosaccharides are efficient substrates for mycobacterial galactan biosynthetic enzymes. Org Biomol Chem 2018; 16:1939-1957. [DOI: 10.1039/c8ob00316e] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Synthetic glycosyl polyprenol phosphates are substrates for enzymes required for cell wall assembly in mycobacteria, including the organism that causes tuberculosis.
Collapse
Affiliation(s)
- Xiaochao Xue
- Alberta Glycomics Centre and Department of Chemistry
- University of Alberta
- Edmonton
- Canada
| | - Ruixiang Blake Zheng
- Alberta Glycomics Centre and Department of Chemistry
- University of Alberta
- Edmonton
- Canada
| | - Akihiko Koizumi
- Alberta Glycomics Centre and Department of Chemistry
- University of Alberta
- Edmonton
- Canada
| | - Ling Han
- Alberta Glycomics Centre and Department of Chemistry
- University of Alberta
- Edmonton
- Canada
| | - John S. Klassen
- Alberta Glycomics Centre and Department of Chemistry
- University of Alberta
- Edmonton
- Canada
| | - Todd L. Lowary
- Alberta Glycomics Centre and Department of Chemistry
- University of Alberta
- Edmonton
- Canada
| |
Collapse
|
9
|
Bols M, Pedersen CM. Silyl-protective groups influencing the reactivity and selectivity in glycosylations. Beilstein J Org Chem 2017; 13:93-105. [PMID: 28228850 PMCID: PMC5301963 DOI: 10.3762/bjoc.13.12] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Accepted: 12/23/2016] [Indexed: 11/26/2022] Open
Abstract
Silyl groups such as TBDPS, TBDMS, TIPS or TMS are well-known and widely used alcohol protective groups in organic chemistry. Cyclic silylene protective groups are also becoming increasingly popular. In carbohydrate chemistry silyl protective groups have frequently been used primarily as an orthogonal protective group to the more commonly used acyl and benzyl protective groups. However, silyl protective groups have significantly different electronic and steric requirements than acyl and alkyl protective groups, which particularly becomes important when two or more neighboring alcohols are silyl protected. Within the last decade polysilylated glycosyl donors have been found to have unusual properties such as high (or low) reactivity or high stereoselectivity. This mini review will summarize these findings.
Collapse
Affiliation(s)
- Mikael Bols
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
| | | |
Collapse
|
10
|
Wesener DA, Levengood MR, Kiessling LL. Comparing Galactan Biosynthesis in Mycobacterium tuberculosis and Corynebacterium diphtheriae. J Biol Chem 2016; 292:2944-2955. [PMID: 28039359 DOI: 10.1074/jbc.m116.759340] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2016] [Revised: 12/28/2016] [Indexed: 11/06/2022] Open
Abstract
The suborder Corynebacterineae encompasses species like Corynebacterium glutamicum, which has been harnessed for industrial production of amino acids, as well as Corynebacterium diphtheriae and Mycobacterium tuberculosis, which cause devastating human diseases. A distinctive component of the Corynebacterineae cell envelope is the mycolyl-arabinogalactan (mAG) complex. The mAG is composed of lipid mycolic acids, and arabinofuranose (Araf) and galactofuranose (Galf) carbohydrate residues. Elucidating microbe-specific differences in mAG composition could advance biotechnological applications and lead to new antimicrobial targets. To this end, we compare and contrast galactan biosynthesis in C. diphtheriae and M. tuberculosis In each species, the galactan is constructed from uridine 5'-diphosphate-α-d-galactofuranose (UDP-Galf), which is generated by the enzyme UDP-galactopyranose mutase (UGM or Glf). UGM and the galactan are essential in M. tuberculosis, but their importance in Corynebacterium species was not known. We show that small molecule inhibitors of UGM impede C. glutamicum growth, suggesting that the galactan is critical in corynebacteria. Previous cell wall analysis data suggest the galactan polymer is longer in mycobacterial species than corynebacterial species. To explore the source of galactan length variation, a C. diphtheriae ortholog of the M. tuberculosis carbohydrate polymerase responsible for the bulk of galactan polymerization, GlfT2, was produced, and its catalytic activity was evaluated. The C. diphtheriae GlfT2 gave rise to shorter polysaccharides than those obtained with the M. tuberculosis GlfT2. These data suggest that GlfT2 alone can influence galactan length. Our results provide tools, both small molecule and genetic, for probing and perturbing the assembly of the Corynebacterineae cell envelope.
Collapse
Affiliation(s)
| | - Matthew R Levengood
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706
| | - Laura L Kiessling
- From the Department of Biochemistry and .,Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706
| |
Collapse
|
11
|
Design and synthesis of phosphoryl-substituted diphenylpyrimidines (Pho-DPPYs) as potent Bruton's tyrosine kinase (BTK) inhibitors: Targeted treatment of B lymphoblastic leukemia cell lines. Bioorg Med Chem 2016; 25:765-772. [PMID: 27956037 DOI: 10.1016/j.bmc.2016.11.054] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Revised: 11/01/2016] [Accepted: 11/28/2016] [Indexed: 12/26/2022]
Abstract
A family of phosphoryl-substituted diphenylpyrimidine derivatives (Pho-DPPYs) were synthesized and biologically evaluated as potent BTK inhibitors in this study. Compound 7b was found to markedly inhibit BTK activity at concentrations of 0.82nmol/L, as well as to suppress the proliferations of B-cell leukemia cell lines (Ramos and Raji) expressing high levels of BTK at concentrations of 3.17μM and 6.69μM. Moreover, flow cytometry analysis results further indicated that 7b promoted cell apoptosis to a substantial degree. In a word, compound 7b is a promising BTK inhibitor for the treatment of B-cell lymphoblastic leukemia.
Collapse
|
12
|
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.
Collapse
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.
| |
Collapse
|
13
|
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.
Collapse
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
| |
Collapse
|
14
|
Yamatsugu K, Splain RA, Kiessling LL. Fidelity and Promiscuity of a Mycobacterial Glycosyltransferase. J Am Chem Soc 2016; 138:9205-11. [PMID: 27302377 DOI: 10.1021/jacs.6b04481] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Members of the genus Mycobacterium cause devastating human diseases, including tuberculosis. Mycobacterium tuberculosis can resist some antibiotics because of its durable and impermeable cell envelope. This barrier is assembled from saccharide building blocks not found in mammals, including galactofuranose (Galf). Within the cell envelope, Galf residues are linked together to afford an essential polysaccharide, termed the galactan. The formation of this polymer is catalyzed by the glycosyltransferase GlfT2, a processive carbohydrate polymerase, which generates a sequence-specific polysaccharide with alternating regioisomeric β(1-5) and β(1-6) Galf linkages. GlfT2 exhibits high fidelity in linkage formation, as it will terminate polymerization rather than deviate from its linkage pattern. These findings suggest that GlfT2 would prefer an acceptor with a canonical alternating β(1-5) and β(1-6) Galf sequence. To test this hypothesis, we devised a synthetic route to assemble oligosaccharides with natural and non-natural sequences. GlfT2 could elongate each of these acceptors, even those with non-natural linkage patterns. These data indicate that the glycosyltransferase is surprisingly promiscuous in its substrate preferences. However, GlfT2 did favor some substrates: it preferentially acted on those in which the lipid-bearing Galf residue was connected to the sequence by a β(1-6) glycosidic linkage. The finding that the relative positioning of the lipid and the non-reducing end of the acceptor influences substrate selectivity is consistent with a role for the lipid in acceptor binding. The data also suggest that the fidelity of GlfT2 for generating an alternating β(1-5) and β(1-6) pattern of Galf residues arises not from preferential substrate binding but during processive elongation. These observations suggest that inhibiting the action of GlfT2 will afford changes in cell wall structure.
Collapse
Affiliation(s)
- Kenzo Yamatsugu
- Department of Chemistry, University of Wisconsin-Madison , 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Rebecca A Splain
- Department of Chemistry, University of Wisconsin-Madison , 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Laura L Kiessling
- Department of Chemistry, University of Wisconsin-Madison , 1101 University Avenue, Madison, Wisconsin 53706, United States.,Department of Biochemistry, University of Wisconsin-Madison , 433 Babcock Drive, Madison, Wisconsin 53706, United States
| |
Collapse
|
15
|
Hofer A, Cremosnik GS, Müller AC, Giambruno R, Trefzer C, Superti-Furga G, Bennett KL, Jessen HJ. A Modular Synthesis of Modified Phosphoanhydrides. Chemistry 2015; 21:10116-22. [PMID: 26033174 DOI: 10.1002/chem.201500838] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Indexed: 11/11/2022]
Abstract
Phosphoanhydrides (P-anhydrides) are ubiquitously occurring modifications in nature. Nucleotides and their conjugates, for example, are among the most important building blocks and signaling molecules in cell biology. To study and manipulate their biological functions, a diverse range of analogues have been developed. Phosphate-modified analogues have been successfully applied to study proteins that depend on these abundant cellular building blocks, but very often both the preparation and purification of these molecules are challenging. This study discloses a general access to P-anhydrides, including different nucleotide probes, that greatly facilitates their preparation and isolation. The convenient and scalable synthesis of, for example, (18) O labeled nucleoside triphosphates holds promise for future applications in phosphoproteomics.
Collapse
Affiliation(s)
- Alexandre Hofer
- Department of Chemistry, University of Zürich, Winterthurerstrasse 190, 8057 Zürich (Switzerland)
| | - Gregor S Cremosnik
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA (UK)
| | - André C Müller
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Lazarettgasse 14, AKH BT 25.3, 1090 Vienna (Austria)
| | - Roberto Giambruno
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Lazarettgasse 14, AKH BT 25.3, 1090 Vienna (Austria)
| | - Claudia Trefzer
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Lazarettgasse 14, AKH BT 25.3, 1090 Vienna (Austria)
| | - Giulio Superti-Furga
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Lazarettgasse 14, AKH BT 25.3, 1090 Vienna (Austria)
| | - Keiryn L Bennett
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Lazarettgasse 14, AKH BT 25.3, 1090 Vienna (Austria)
| | - Henning J Jessen
- Department of Chemistry, University of Zürich, Winterthurerstrasse 190, 8057 Zürich (Switzerland).
| |
Collapse
|
16
|
Smithen DA, Forget SM, McCormick NE, Syvitski RT, Jakeman DL. Polyphosphate-containing bisubstrate analogues as inhibitors of a bacterial cell wall thymidylyltransferase. Org Biomol Chem 2015; 13:3347-50. [DOI: 10.1039/c4ob02583k] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The first synthesis and evaluation of bisubstrate analogues with a thymidylyltransferase is reported. WaterLOGSY NMR and kinetic analyses provide insight into bisubstrate analogue binding.
Collapse
Affiliation(s)
| | | | | | | | - David L. Jakeman
- Department of Chemistry
- Dalhousie University
- Halifax
- Canada
- College of Pharmacy
| |
Collapse
|
17
|
Qiao Y, Lebar MD, Schirner K, Schaefer K, Tsukamoto H, Kahne D, Walker S. Detection of lipid-linked peptidoglycan precursors by exploiting an unexpected transpeptidase reaction. J Am Chem Soc 2014; 136:14678-81. [PMID: 25291014 PMCID: PMC4210121 DOI: 10.1021/ja508147s] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
![]()
Penicillin-binding
proteins (PBPs) are involved in the synthesis
and remodeling of bacterial peptidoglycan (PG). Staphylococcus
aureus expresses four PBPs. Genetic studies in S.
aureus have implicated PBP4 in the formation of highly cross-linked
PG, but biochemical studies have not reached a consensus on its primary
enzymatic activity. Using synthetic Lipid II, we show here that PBP4
preferentially acts as a transpeptidase (TP) in vitro. Moreover, it is the PBP primarily responsible for incorporating
exogenous d-amino acids into cellular PG, implying that it
also has TP activity in vivo. Notably, PBP4 efficiently
exchanges d-amino acids not only into PG polymers but also
into the PG monomers Lipid I and Lipid II. This is the first demonstration
that any TP domain of a PBP can activate the PG monomer building blocks.
Exploiting the promiscuous TP activity of PBP4, we developed a simple,
highly sensitive assay to detect cellular pools of lipid-linked PG
precursors, which are of notoriously low abundance. This method, which
addresses a longstanding problem, is useful for assessing how genetic
and pharmacological perturbations affect precursor levels, and may
facilitate studies to elucidate antibiotic mechanism of action.
Collapse
Affiliation(s)
- Yuan Qiao
- Chemical Biology Program, Harvard University , Cambridge, Massachusetts 02138, United States
| | | | | | | | | | | | | |
Collapse
|