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Gennari A, Simon R, Benvenutti EV, Nicolodi S, Renard G, Chies JM, Volpato G, Volken de Souza CF. Magnetic core-shell cellulose system for the oriented immobilization of a recombinant β-galactosidase with a protein tag. Int J Biol Macromol 2024; 256:128418. [PMID: 38029902 DOI: 10.1016/j.ijbiomac.2023.128418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 11/22/2023] [Accepted: 11/23/2023] [Indexed: 12/01/2023]
Abstract
The objective of this study was to immobilize a recombinant β-galactosidase (Gal) tagged with a cellulose-binding domain (CBD) onto a magnetic core-shell (CS) cellulose system. After 30 min of reaction, 4 U/capsule were immobilized (CS@Gal), resulting in levels of yield and efficiency exceeding 80 %. The optimal temperature for β-galactosidase-CBD activity increased from 40 to 50 °C following oriented immobilization. The inhibitory effect of galactose decreased in the enzyme reactions catalyzed by CS@Gal, and Mg2+ increased the immobilized enzyme activity by 40 % in the magnetic CS cellulose system. The relative enzyme activity of the CS@Gal was 20 % higher than that of the soluble enzyme activity after 20 min at 50 °C. The CS support and CS@Gal capsules exhibited an average size of 8 ± 1 mm, with the structure of the shell (alginate-pectin-cellulose) enveloping and isolating the magnetic core. The immobilized β-galactosidase-CBD within the magnetic CS cellulose system retained ∼80 % of its capacity to hydrolyze lactose from skim milk after 10 reuse cycles. This study unveils a novel and promising support for the oriented immobilization of recombinant β-galactosidase using a magnetic CS system and a CBD tag. This support facilitates β-galactosidase reuse and efficient separation, consequently enhancing the catalytic properties of the enzyme.
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Affiliation(s)
- Adriano Gennari
- Laboratório de Biotecnologia de Alimentos, Universidade do Vale do Taquari - Univates, Lajeado, RS, Brazil; Programa de Pós-Graduação em Biotecnologia, Universidade do Vale do Taquari - Univates, Lajeado, RS, Brazil
| | - Renate Simon
- Laboratório de Biotecnologia de Alimentos, Universidade do Vale do Taquari - Univates, Lajeado, RS, Brazil
| | | | - Sabrina Nicolodi
- Instituto de Física, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Gaby Renard
- Quatro G Pesquisa & Desenvolvimento Ltda, Porto Alegre, RS, Brazil
| | | | - Giandra Volpato
- Instituto Federal de Educação, Ciência e Tecnologia do Rio Grande do Sul - IFRS, Campus Porto Alegre, Porto Alegre, RS, Brazil
| | - Claucia Fernanda Volken de Souza
- Laboratório de Biotecnologia de Alimentos, Universidade do Vale do Taquari - Univates, Lajeado, RS, Brazil; Programa de Pós-Graduação em Biotecnologia, Universidade do Vale do Taquari - Univates, Lajeado, RS, Brazil.
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2
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Soni V, Rosenn EH, Venkataraman R. Insights into the central role of N-acetyl-glucosamine-1-phosphate uridyltransferase (GlmU) in peptidoglycan metabolism and its potential as a therapeutic target. Biochem J 2023; 480:1147-1164. [PMID: 37498748 DOI: 10.1042/bcj20230173] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 07/07/2023] [Accepted: 07/14/2023] [Indexed: 07/29/2023]
Abstract
Several decades after the discovery of the first antibiotic (penicillin) microbes have evolved novel mechanisms of resistance; endangering not only our abilities to combat future bacterial pandemics but many other clinical challenges such as acquired infections during surgeries. Antimicrobial resistance (AMR) is attributed to the mismanagement and overuse of these medications and is complicated by a slower rate of the discovery of novel drugs and targets. Bacterial peptidoglycan (PG), a three-dimensional mesh of glycan units, is the foundation of the cell wall that protects bacteria against environmental insults. A significant percentage of drugs target PG, however, these have been rendered ineffective due to growing drug resistance. Identifying novel druggable targets is, therefore, imperative. Uridine diphosphate N-acetylglucosamine (UDP-GlcNAc) is one of the key building blocks in PG production, biosynthesized by the bifunctional enzyme N-acetyl-glucosamine-1-phosphate uridyltransferase (GlmU). UDP-GlcNAc metabolism has been studied in many organisms, but it holds some distinctive features in bacteria, especially regarding the bacterial GlmU enzyme. In this review, we provide an overview of different steps in PG biogenesis, discuss the biochemistry of GlmU, and summarize the characteristic structural elements of bacterial GlmU vital to its catalytic function. Finally, we will discuss various studies on the development of GlmU inhibitors and their significance in aiding future drug discoveries.
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Affiliation(s)
- Vijay Soni
- Division of Infectious Diseases, Weill Department of Medicine, Weill Cornell Medicine, New York, NY 10065, U.S.A
| | - Eric H Rosenn
- Tel Aviv University School of Medicine, Tel Aviv 6997801, Israel
| | - Ramya Venkataraman
- Laboratory of Innate Immunity, National Institute of Immunology, New Delhi 110067, India
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3
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Identification of Mtb GlmU Uridyltransferase Domain Inhibitors by Ligand-Based and Structure-Based Drug Design Approaches. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27092805. [PMID: 35566155 PMCID: PMC9105790 DOI: 10.3390/molecules27092805] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 04/04/2022] [Accepted: 04/07/2022] [Indexed: 01/09/2023]
Abstract
Targeting enzymes that play a role in the biosynthesis of the bacterial cell wall has long been a strategy for antibacterial discovery. In particular, the cell wall of Mycobacterium tuberculosis (Mtb) is a complex of three layers, one of which is Peptidoglycan, an essential component providing rigidity and strength. UDP-GlcNAc, a precursor for the synthesis of peptidoglycan, is formed by GlmU, a bi-functional enzyme. Inhibiting GlmU Uridyltransferase activity has been proven to be an effective anti-bacterial, but its similarity with human enzymes has been a deterrent to drug development. To develop Mtb selective hits, the Mtb GlmU substrate binding pocket was compared with structurally similar human enzymes to identify selectivity determining factors. Substrate binding pockets and conformational changes upon substrate binding were analyzed and MD simulations with substrates were performed to quantify crucial interactions to develop critical pharmacophore features. Thereafter, two strategies were applied to propose potent and selective bacterial GlmU Uridyltransferase domain inhibitors: (i) optimization of existing inhibitors, and (ii) identification by virtual screening. The binding modes of hits identified from virtual screening and ligand growing approaches were evaluated further for their ability to retain stable contacts within the pocket during 20 ns MD simulations. Hits that are predicted to be more potent than existing inhibitors and selective against human homologues could be of great interest for rejuvenating drug discovery efforts towards targeting the Mtb cell wall for antibacterial discovery.
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Gennari A, Simon R, Sperotto NDDM, Bizarro CV, Basso LA, Machado P, Benvenutti EV, Renard G, Chies JM, Volpato G, Volken de Souza CF. Application of cellulosic materials as supports for single-step purification and immobilization of a recombinant β-galactosidase via cellulose-binding domain. Int J Biol Macromol 2022; 199:307-317. [PMID: 35007635 DOI: 10.1016/j.ijbiomac.2022.01.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 12/17/2021] [Accepted: 01/02/2022] [Indexed: 02/06/2023]
Abstract
This study aimed to develop single-step purification and immobilization processes on cellulosic supports of β-galactosidase from Kluyveromyces sp. combined with the Cellulose-Binding Domain (CBD) tag. After 15 min of immobilization, with an enzymatic load of 150 U/gsupport, expressed activity values reached 106.88 (microcrystalline cellulose), 115.03 (alkaline nanocellulose), and 108.47 IU/g (acid nanocellulose). The derivatives produced were less sensitive to the presence of galactose in comparison with the soluble purified enzyme. Among the cations assessed (Na+, K+, Mg2+, and Ca2+), magnesium provided the highest increase in the enzymatic activity of β-galactosidases immobilized on cellulosic supports. Supports and derivatives showed no cytotoxic effect on the investigated cell cultures (HepG2 and Vero). Derivatives showed high operational stability in the hydrolysis of milk lactose and retained from 53 to 64% of their hydrolysis capacity after 40 reuse cycles. This study obtained biocatalyzers with promising characteristics for application in the food industry. Biocatalyzers were obtained through a low-cost one-step sustainable bioprocess of purification and immobilization of a β-galactosidase on cellulose via CBD.
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Affiliation(s)
- Adriano Gennari
- Laboratório de Biotecnologia de Alimentos, Brazil; Universidade do Vale do Taquari - Univates, Lajeado, RS, Brazil
| | - Renate Simon
- Laboratório de Biotecnologia de Alimentos, Brazil
| | | | - Cristiano Valim Bizarro
- Instituto Nacional de Ciência e Tecnologia em Tuberculose, Centro de Pesquisas em Biologia Molecular e Funcional, Brazil; Programa de Pós-Graduação em Biologia Celular e Molecular, Brazil
| | - Luiz Augusto Basso
- Instituto Nacional de Ciência e Tecnologia em Tuberculose, Centro de Pesquisas em Biologia Molecular e Funcional, Brazil; Programa de Pós-Graduação em Biologia Celular e Molecular, Brazil; Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Pablo Machado
- Instituto Nacional de Ciência e Tecnologia em Tuberculose, Centro de Pesquisas em Biologia Molecular e Funcional, Brazil; Programa de Pós-Graduação em Biologia Celular e Molecular, Brazil; Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | | | - Gaby Renard
- Instituto Nacional de Ciência e Tecnologia em Tuberculose, Centro de Pesquisas em Biologia Molecular e Funcional, Brazil
| | | | - Giandra Volpato
- Instituto Federal de Educação, Ciência e Tecnologia do Rio Grande do Sul - IFRS, Campus Porto Alegre, Porto Alegre, RS, Brazil
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5
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Unique C-terminal extension and interactome of Mycobacterium tuberculosis GlmU impacts it's in vivo function and the survival of pathogen. Biochem J 2021; 478:2081-2099. [PMID: 33955473 DOI: 10.1042/bcj20210170] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 05/01/2021] [Accepted: 05/06/2021] [Indexed: 11/17/2022]
Abstract
N-acetyl glucosamine-1-phosphate uridyltransferase (GlmU) is a bifunctional enzyme involved in the biosynthesis of Uridine diphosphate N-acetylglucosamine (UDP-GlcNAc). UDP-GlcNAc is a critical precursor for the synthesis of peptidoglycan and other cell wall components. The absence of a homolog in eukaryotes makes GlmU an attractive target for therapeutic intervention. Mycobacterium tuberculosis GlmU (GlmUMt) has features, such as a C-terminal extension, that are not present in GlmUorthologs from other bacteria. Here, we set out to determine the uniqueness of GlmUMt by performing in vivo complementation experiments using RvΔglmU mutant. We find that any deletion of the carboxy-terminal extension region of GlmUMt abolishes its ability to complement the function of GlmUMt. Results show orthologs of GlmU, including its closest ortholog, from Mycobacterium smegmatis, cannot complement the function of GlmUMt. Furthermore, the co-expression of GlmUMt domain deletion mutants with either acetyl or uridyltransferase activities failed to rescue the function. However, co-expression of GlmUMt point mutants with either acetyl or uridyltransferase activities successfully restored the biological function of GlmUMt, likely due to the formation of heterotrimers. Based on the interactome experiments, we speculate that GlmUMt participates in unique interactions essential for its in vivo function.
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Gennari A, Simon R, de Andrade BC, Saraiva Macedo Timmers LF, Milani Martins VL, Renard G, Chies JM, Volpato G, Volken de Souza CF. Production of beta-galactosidase fused to a cellulose-binding domain for application in sustainable industrial processes. BIORESOURCE TECHNOLOGY 2021; 326:124747. [PMID: 33517047 DOI: 10.1016/j.biortech.2021.124747] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 01/14/2021] [Accepted: 01/15/2021] [Indexed: 06/12/2023]
Abstract
This study aimed to produce and characterize a recombinant Kluyveromyces sp. β-galactosidase fused to a cellulose-binding domain (CBD) for industrial application. In expression assays, the highest enzymatic activities occurred after 48 h induction on Escherichia coli C41(DE3) strain at 20 °C in Terrific Broth (TB) culture medium, using isopropyl β-d-1-thiogalactopyranoside (IPTG) 0.5 mM (108.77 U/mL) or lactose 5 g/L (93.10 U/mL) as inducers. Cultures at bioreactor scale indicated that higher product yield values in relation to biomass (2000 U/g) and productivity (0.72 U/mL.h) were obtained in culture media containing higher protein concentration. The recombinant enzyme showed high binding affinity to nanocellulose, reaching both immobilization yield and efficiency values of approximately 70% at pH 7.0 after 10 min reaction. The results of the present study pointed out a strategy for recombinant β-galactosidase-CBD production and immobilization, aiming toward the application in sustainable industrial processes using low-cost inputs.
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Affiliation(s)
- Adriano Gennari
- Laboratório de Biotecnologia de Alimentos, Universidade do Vale do Taquari - Univates, Lajeado, RS, Brazil; Programa de Pós-Graduação em Biotecnologia, Universidade do Vale do Taquari - Univates, Lajeado, RS, Brazil
| | - Renate Simon
- Laboratório de Biotecnologia de Alimentos, Universidade do Vale do Taquari - Univates, Lajeado, RS, Brazil
| | - Bruna Coelho de Andrade
- Laboratório de Biotecnologia de Alimentos, Universidade do Vale do Taquari - Univates, Lajeado, RS, Brazil; Programa de Pós-Graduação em Biotecnologia, Universidade do Vale do Taquari - Univates, Lajeado, RS, Brazil
| | | | - Vera Lúcia Milani Martins
- Instituto Federal de Educação, Ciência e Tecnologia do Rio Grande do Sul - IFRS, Campus Porto Alegre, Porto Alegre, RS, Brazil
| | - Gaby Renard
- Centro de Pesquisa em Biologia Molecular e Funcional, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | | | - Giandra Volpato
- Instituto Federal de Educação, Ciência e Tecnologia do Rio Grande do Sul - IFRS, Campus Porto Alegre, Porto Alegre, RS, Brazil
| | - Claucia Fernanda Volken de Souza
- Laboratório de Biotecnologia de Alimentos, Universidade do Vale do Taquari - Univates, Lajeado, RS, Brazil; Programa de Pós-Graduação em Biotecnologia, Universidade do Vale do Taquari - Univates, Lajeado, RS, Brazil.
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7
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Gogoi P, Mordina P, Kanaujia SP. Exploiting the rationale behind substrate recognition by promiscuous thermophilic NDP-sugar pyrophosphorylase for expanding glycorandomization: an in silico study. J Biomol Struct Dyn 2020; 39:6099-6111. [PMID: 32692307 DOI: 10.1080/07391102.2020.1796795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The fundamental substrates for protein glycosylation are provided by a group of enzymes known as NDP-sugar pyrophosphorylases (NSPases) which utilize nucleotide triphosphate (NTP) and sugar 1-phosphate to catalyze the formation of nucleotide diphospho-sugar (NDP-sugar). The promiscuous nature of NSPases is often exploited during chemoenzymatic glycorandomization in the pursuit of novel therapeutics. However, till date, the number of inherently promiscuous NSPases reported and the rationale behind their promiscuity is meager. In this study, we have identified a set of NSPases from a hyperthermophilic archaeon Pyrococcus horikoshii OT3 to identify probable candidates for glycorandomization. We identified a set of NSPases that include both substrate-specific and substrate-promiscuous NSPases with a visible predominance of the latter group. The rationale behind the promiscuity (or specificity) vividly lies in the repertoire of amino acid residues that assemble the active site for recognition of the substrate moiety. Furthermore, the absence of a function-specific auxiliary domain promotes substrate promiscuity in NSPases. This study, thus, provides a novel set of thermophilic NSPases that can be employed for chemoenzymatic glycorandomization. More importantly, identification of the residues that render substrate promiscuity (or specificity) would assist in sequence-based rational engineering of NSPases for enhanced glycorandomization. Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Prerana Gogoi
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam, India
| | - Prerana Mordina
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam, India
| | - Shankar Prasad Kanaujia
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam, India
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8
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Vithani N, Prakash B, Nair NN. Mechanism of Nucleotidyltransfer Reaction and Role of Mg 2+ Ion in Sugar Nucleotidyltransferases. Biophys J 2020; 119:619-627. [PMID: 32645293 DOI: 10.1016/j.bpj.2020.06.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 05/19/2020] [Accepted: 06/17/2020] [Indexed: 11/17/2022] Open
Abstract
Sugar nucleotidyl transferases (SNTs) catalyze nucleotidyltransfer reactions to form sugar-nucleotides and pyrophosphate in the presence of two Mg2+ ions (Mg2+A and Mg2+B). We unveil the mechanism and free energetics of nucleotidyl transfer reaction in an SNT called GlmU through hybrid quantum mechanics-molecular mechanics molecular dynamics simulations and free energy calculations. The study identifies the roles of the active site residues and the Mg2+ ions in catalyzing the reaction. Of great significance, we are able to compare the free energy barrier for the reaction with that for the Mg2+-assisted release of the product (i.e., pyrophosphate) into the solution, shedding light on the general mechanistic and kinetic aspects of catalysis by SNTs.
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Affiliation(s)
- Neha Vithani
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur, India
| | - Balaji Prakash
- Department of Molecular Nutrition, CSIR-Central Food Technological Research Institute, Mysore, India.
| | - Nisanth N Nair
- Department of Chemistry, Indian Institute of Technology, Kanpur, India.
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9
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Shetye GS, Franzblau SG, Cho S. New tuberculosis drug targets, their inhibitors, and potential therapeutic impact. Transl Res 2020; 220:68-97. [PMID: 32275897 DOI: 10.1016/j.trsl.2020.03.007] [Citation(s) in RCA: 88] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 02/28/2020] [Accepted: 03/09/2020] [Indexed: 11/18/2022]
Abstract
The current tuberculosis (TB) predicament poses numerous challenges and therefore every incremental scientific work and all positive socio-political engagements, are steps taken in the right direction to eradicate TB. Progression of the late stage TB-drug pipeline into the clinics is an immediate deliverable of this global effort. At the same time, fueling basic research and pursuing early discovery work must be sustained to maintain a healthy TB-drug pipeline. This review encompasses a broad analysis of chemotherapeutic strategies that target the DNA replication, protein synthesis, cell wall biosynthesis, energy metabolism and proteolysis of Mycobacterium tuberculosis (Mtb). It includes a status check of the current TB-drug pipeline with a focus on the associated biology, emerging targets, and their promising chemical inhibitors. Potential synergies and/or gaps within or across different chemotherapeutic strategies are systematically reviewed as well.
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Affiliation(s)
- Gauri S Shetye
- Institute for Tuberculosis Research, College of Pharmacy, University of Illinois at Chicago, Chicago, Illinois
| | - Scott G Franzblau
- Institute for Tuberculosis Research, College of Pharmacy, University of Illinois at Chicago, Chicago, Illinois
| | - Sanghyun Cho
- Institute for Tuberculosis Research, College of Pharmacy, University of Illinois at Chicago, Chicago, Illinois.
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10
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Raimi OG, Hurtado-Guerrero R, Borodkin V, Ferenbach A, Urbaniak MD, Ferguson MAJ, van Aalten DMF. A mechanism-inspired UDP- N-acetylglucosamine pyrophosphorylase inhibitor. RSC Chem Biol 2020; 1:13-25. [PMID: 34458745 PMCID: PMC8386105 DOI: 10.1039/c9cb00017h] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Accepted: 02/13/2020] [Indexed: 11/21/2022] Open
Abstract
UDP-N-acetylglucosamine pyrophosphorylase (UAP1) catalyses the last step in eukaryotic biosynthesis of uridine diphosphate-N-acetylglucosamine (UDP-GlcNAc), converting UTP and GlcNAc-1P to the sugar nucleotide. Gene disruption studies have shown that this gene is essential in eukaryotes and a possible antifungal target, yet no inhibitors of fungal UAP1 have so far been reported. Here we describe the crystal structures of substrate/product complexes of UAP1 from Aspergillus fumigatus that together provide snapshots of catalysis. A structure with UDP-GlcNAc, pyrophosphate and Mg2+ provides the first Michaelis complex trapped for this class of enzyme, revealing the structural basis of the previously reported Mg2+ dependence and direct observation of pyrophosphorolysis. We also show that a highly conserved lysine mimics the role of a second metal observed in structures of bacterial orthologues. A mechanism-inspired UTP α,β-methylenebisphosphonate analogue (meUTP) was designed and synthesized and was shown to be a micromolar inhibitor of the enzyme. The mechanistic insights and inhibitor described here will facilitate future studies towards the discovery of small molecule inhibitors of this currently unexploited potential antifungal drug target. UDP-N-acetylglucosamine pyrophosphorylase (UAP1) catalyses the last step in eukaryotic biosynthesis of uridine diphosphate-N-acetylglucosamine (UDP-GlcNAc), converting UTP and GlcNAc-1P to the sugar nucleotide.![]()
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Affiliation(s)
- Olawale G Raimi
- Division of Gene Regulation and Expression, School of Life Sciences, University of Dundee Dow Street DD1 5EH Dundee UK
| | - Ramon Hurtado-Guerrero
- Division of Gene Regulation and Expression, School of Life Sciences, University of Dundee Dow Street DD1 5EH Dundee UK
| | - Vladimir Borodkin
- Division of Gene Regulation and Expression, School of Life Sciences, University of Dundee Dow Street DD1 5EH Dundee UK
| | - Andrew Ferenbach
- Division of Gene Regulation and Expression, School of Life Sciences, University of Dundee Dow Street DD1 5EH Dundee UK
| | - Michael D Urbaniak
- Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee Dow Street DD1 5EH Dundee UK
| | - Michael A J Ferguson
- Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee Dow Street DD1 5EH Dundee UK
| | - Daan M F van Aalten
- Division of Gene Regulation and Expression, School of Life Sciences, University of Dundee Dow Street DD1 5EH Dundee UK
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11
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Classification, characterization and structural analysis of sugar nucleotidylyltransferase family of enzymes. Biochem Biophys Res Commun 2020; 525:780-785. [PMID: 32147095 DOI: 10.1016/j.bbrc.2020.02.148] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 02/24/2020] [Indexed: 11/22/2022]
Abstract
Sugar Nucleotidyl Transferases (SNTs) constitute a large family of enzymes that play important metabolic roles. Earlier, for one such SNT, termed N-acetylglucosamine-1-phosphate uridyltransferase- GlmU, we had established that two magnesium ions - Mg2+A and Mg2+B - catalyze the sugar-nucleotidyl transfer reaction. Despite a common structural framework that SNTs share, we recognized key differences around the active-site based on the analysis of available structures. Based on these differences, we had classified SNTs into two major groups, Group - I & II; and further, variation in 'Mg2+A-stabilizing motifs' led us to sub-classify them into five distinct sub-groups. Since group specific conservation of 'Mg2+A-stabilizing motifs' was based only for 45 available structures, here we validate this via an exhaustive analysis of 1,42,025 protein sequences. Previously, we had hypothesized that a metal-ion-catalyzed mechanism would be operative in all SNTs. Here, we validate it biochemically and establish that Mg2+ is a strict requirement for nucleotidyl transfer reactions in every group or sub-group and that a common metal ion dependent mechanism operates in SNTs. Further, mutating Mg2+A coordinating residue in each sub-group led to abolished catalysis, indicating an important role for both of these residues and suggest that SNTs employ variations over 'a conserved catalytic mechanism mediated by Mg2+ ion(s)', to bring about functional diversity. This would constitute a comprehensive study to establish the catalytic mechanism across the family of SNTs.
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12
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Structural basis of glycogen metabolism in bacteria. Biochem J 2019; 476:2059-2092. [PMID: 31366571 DOI: 10.1042/bcj20170558] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 07/11/2019] [Accepted: 07/15/2019] [Indexed: 01/25/2023]
Abstract
The evolution of metabolic pathways is a major force behind natural selection. In the spotlight of such process lies the structural evolution of the enzymatic machinery responsible for the central energy metabolism. Specifically, glycogen metabolism has emerged to allow organisms to save available environmental surplus of carbon and energy, using dedicated glucose polymers as a storage compartment that can be mobilized at future demand. The origins of such adaptive advantage rely on the acquisition of an enzymatic system for the biosynthesis and degradation of glycogen, along with mechanisms to balance the assembly and disassembly rate of this polysaccharide, in order to store and recover glucose according to cell energy needs. The first step in the classical bacterial glycogen biosynthetic pathway is carried out by the adenosine 5'-diphosphate (ADP)-glucose pyrophosphorylase. This allosteric enzyme synthesizes ADP-glucose and acts as a point of regulation. The second step is carried out by the glycogen synthase, an enzyme that generates linear α-(1→4)-linked glucose chains, whereas the third step catalyzed by the branching enzyme produces α-(1→6)-linked glucan branches in the polymer. Two enzymes facilitate glycogen degradation: glycogen phosphorylase, which functions as an α-(1→4)-depolymerizing enzyme, and the debranching enzyme that catalyzes the removal of α-(1→6)-linked ramifications. In this work, we rationalize the structural basis of glycogen metabolism in bacteria to the light of the current knowledge. We describe and discuss the remarkable progress made in the understanding of the molecular mechanisms of substrate recognition and product release, allosteric regulation and catalysis of all those enzymes.
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13
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Vithani N, Ankush Jagtap PK, Verma SK, Tripathi R, Awasthi S, Nair NN, Prakash B. Mechanism of Mg 2+-Accompanied Product Release in Sugar Nucleotidyltransferases. Structure 2019. [PMID: 29514078 DOI: 10.1016/j.str.2018.02.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The nucleotidyl transfer reaction, catalyzed by sugar nucleotidyltransferases (SNTs), is assisted by two active site Mg2+ ions. While studying this reaction using X-ray crystallography, we captured snapshots of the pyrophosphate (product) as it exits along a pocket. Surprisingly, one of the active site Mg2+ ions remains coordinated to the exiting pyrophosphate. This hints at the participation of Mg2+ in the process of product release, besides its role in catalyzing nucleotidyl transfer. These observations are further supported by enhanced sampling molecular dynamics simulations. Free energy computations suggest that the product release is likely to be rate limiting in SNTs, and the origin of the high free energy barrier for product release could be traced back to the "slow" conformational change of an Arg residue at the exit end of the pocket. These results establish a dual role for Mg2+, and propose a general mechanism of product release during the nucleotidyl transfer by SNTs.
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Affiliation(s)
- Neha Vithani
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
| | - Pravin Kumar Ankush Jagtap
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
| | - Sunil Kumar Verma
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
| | - Ravi Tripathi
- Department of Chemistry, Indian Institute of Technology, Kanpur 208016, India
| | - Shalini Awasthi
- Department of Chemistry, Indian Institute of Technology, Kanpur 208016, India
| | - Nisanth N Nair
- Department of Chemistry, Indian Institute of Technology, Kanpur 208016, India.
| | - Balaji Prakash
- Department of Molecular Nutrition, CSIR-Central Food Technological Research Institute, Mysore 570020, India.
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14
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Honda Y, Nakano S, Ito S, Dadashipour M, Zhang Z, Kawarabayasi Y. Improvement of ST0452 N-Acetylglucosamine-1-Phosphate Uridyltransferase Activity by the Cooperative Effect of Two Single Mutations Identified through Structure-Based Protein Engineering. Appl Environ Microbiol 2018; 84:e02213-18. [PMID: 30291121 PMCID: PMC6275352 DOI: 10.1128/aem.02213-18] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Accepted: 09/25/2018] [Indexed: 11/20/2022] Open
Abstract
We showed previously that the Y97N mutant of the ST0452 protein, isolated from Sulfolobus tokodaii, exhibited over 4 times higher N-acetylglucosamine-1-phosphate (GlcNAc-1-P) uridyltransferase (UTase) activity, compared with that of the wild-type ST0452 protein. We determined the three-dimensional structure of the Y97N protein to explore the detailed mechanism underlying this increased activity. The overall structure was almost identical to that of the wild-type ST0452 protein (PDB ID 2GGO), with residue 97 (Asn) interacting with the O-5 atom of N-acetylglucosamine (GlcNAc) in the complex without metal ions. The same interaction was observed for Escherichia coli GlmU in the absence of metal ions. These observations indicated that the three-dimensional structure of the Y97N protein was not changed by this substitution but the interactions with the substrate were slightly modified, which might cause the activity to increase. The crystal structure of the Y97N protein also showed that positions 146 (Glu) and 80 (Thr) formed interactions with GlcNAc, and an engineering strategy was applied to these residues to increase activity. All proteins substituted at position 146 had drastically decreased activities, whereas several proteins substituted at position 80 showed higher GlcNAc-1-P UTase activity, compared to that of the wild-type protein. The substituted amino acids at positions 80 and 97 might result in optimized interactions with the substrate; therefore, we predicted that the combination of these two substitutions might cooperatively increase GlcNAc-1-P UTase activity. Of the four double mutant ST0452 proteins generated, T80S/Y97N showed 6.5-times-higher activity, compared to that of the wild-type ST0452 protein, revealing that these two substituted residues functioned cooperatively to increase GlcNAc-1-P UTase activity.IMPORTANCE We demonstrated that the enzymatic activity of a thermostable protein was over 4 times higher than that of the wild-type protein following substitution of a single amino acid, without affecting its thermostability. The three-dimensional structure of the improved mutant protein complexed with substrate was determined. The same overall structure and interaction between the substituted residue and the GlcNAc substrate as observed in the well-characterized bacterial enzyme suggested that the substitution of Tyr at position 97 by Asn might slightly change the interaction. This subtle change in the interaction might potentially increase the GlcNAc-1-P UTase activity of the mutant protein. These observations indicated that a drastic change in the structure of a natural thermostable enzyme is not necessary to increase its activity; a subtle change in the interaction with the substrate might be sufficient. Cooperative effects were observed in the appropriate double mutant protein. This work provides useful information for the future engineering of natural enzymes.
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Affiliation(s)
- Yuki Honda
- Laboratory for Functional Genomics of Extremophiles, Faculty of Agriculture, Kyushu University, Fukuoka, Japan
- Faculty of Science, Nara Women's University, Nara, Japan
| | - Shogo Nakano
- Graduate Division of Nutritional and Environmental Sciences, University of Shizuoka, Shizuoka, Japan
| | - Sohei Ito
- Graduate Division of Nutritional and Environmental Sciences, University of Shizuoka, Shizuoka, Japan
| | - Mohammad Dadashipour
- Laboratory for Functional Genomics of Extremophiles, Faculty of Agriculture, Kyushu University, Fukuoka, Japan
| | - Zilian Zhang
- State Key Laboratory of Marine Environmental Science, Institute of Marine Microbes and Ecospheres, Xiamen University, Xiamen, People's Republic of China
| | - Yutaka Kawarabayasi
- Laboratory for Functional Genomics of Extremophiles, Faculty of Agriculture, Kyushu University, Fukuoka, Japan
- National Institute of Advanced Industrial Science and Technology (AIST), Bioproduction Research Institute, Ibaraki, Japan
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15
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Bais VS, Batra S, Prakash B. Identification of two highly promiscuous thermostable sugar nucleotidylyltransferases for glycorandomization. FEBS J 2018; 285:2840-2855. [PMID: 29806742 DOI: 10.1111/febs.14521] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Revised: 04/14/2018] [Accepted: 05/23/2018] [Indexed: 01/22/2023]
Abstract
Glycorandomization is a process that improves the efficacy of glycoconjugates by the addition of a diverse array of sugars to secondary metabolites and antibiotics of pharmaceutical importance. This process, which employs sugar nucleotidylyltransferases (SNTs) and glycosyl transferases (GTs) in tandem, would benefit by the employment of promiscuous enzymes, i.e. those with the ability to utilize diverse noncanonical substrates. As promiscuous GTs are available, here we set out to identify promiscuous SNTs. For this, we began with a detailed family-wide characterization of SNTs. Earlier, we had proposed that SNTs could be classified into two major groups - I and II. They share a common structural framework and utilize a similar catalytic mechanism. Subtle variations in the way two magnesium ions - MgA2+ and MgB2+ - are stabilized by metal ion coordination motifs led to their classification into diverse subgroups viz. I-A, I-B, I-C, II-A, and II-B. Based on this classification, here we investigate promiscuity across the entire family of SNTs. We study the utilization of several sugar phosphates and nucleotides by the various subgroups of SNTs to understand substrate specificity and promiscuity in these. We find that promiscuity is prevalent among SNTs; and in particular, in the thermophilic homologs. In principle, promiscuity profiling identified four new SNTs that can be employed for the production of sugar-nucleotide libraries. However, assaying for their ability to simultaneously utilize multiple substrates in a single-pot reaction, we find two thermophilic SNTs- TMGA , an adenylyltransferase from Thermotoga maritima and PHGT , a thymidylyltransferase from Pyrococcus horikoshii that are readily employable for the production of diverse sugar-nucleotides.
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Affiliation(s)
- Vaibhav Singh Bais
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur, India
| | - Sahil Batra
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur, India
| | - Balaji Prakash
- Department of Molecular Nutrition, CSIR-Central Food Technological Research Institute, Mysore, India
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16
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Craggs PD, Mouilleron S, Rejzek M, de Chiara C, Young RJ, Field RA, Argyrou A, de Carvalho LPS. The Mechanism of Acetyl Transfer Catalyzed by Mycobacterium tuberculosis GlmU. Biochemistry 2018; 57:3387-3401. [PMID: 29684272 PMCID: PMC6011181 DOI: 10.1021/acs.biochem.8b00121] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The biosynthetic pathway of peptidoglycan is essential for Mycobacterium tuberculosis. We report here the acetyltransferase substrate specificity and catalytic mechanism of the bifunctional N-acetyltransferase/uridylyltransferase from M. tuberculosis (GlmU). This enzyme is responsible for the final two steps of the synthesis of UDP- N-acetylglucosamine, which is an essential precursor of peptidoglycan, from glucosamine 1-phosphate, acetyl-coenzyme A, and uridine 5'-triphosphate. GlmU utilizes ternary complex formation to transfer an acetyl from acetyl-coenzyme A to glucosamine 1-phosphate to form N-acetylglucosamine 1-phosphate. Steady-state kinetic studies and equilibrium binding experiments indicate that GlmU follows a steady-state ordered kinetic mechanism, with acetyl-coenzyme A binding first, which triggers a conformational change in GlmU, followed by glucosamine 1-phosphate binding. Coenzyme A is the last product to dissociate. Chemistry is partially rate-limiting as indicated by pH-rate studies and solvent kinetic isotope effects. A novel crystal structure of a mimic of the Michaelis complex, with glucose 1-phosphate and acetyl-coenzyme A, helps us to propose the residues involved in deprotonation of glucosamine 1-phosphate and the loop movement that likely generates the active site required for glucosamine 1-phosphate to bind. Together, these results pave the way for the rational discovery of improved inhibitors against M. tuberculosis GlmU, some of which might become candidates for antibiotic discovery programs.
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Affiliation(s)
- Peter D Craggs
- Platform Technology and Science , GlaxoSmithKline , Stevenage , U.K
| | | | | | | | - Robert J Young
- Platform Technology and Science , GlaxoSmithKline , Stevenage , U.K
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17
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Phosphoribosyl Diphosphate (PRPP): Biosynthesis, Enzymology, Utilization, and Metabolic Significance. Microbiol Mol Biol Rev 2016; 81:81/1/e00040-16. [PMID: 28031352 DOI: 10.1128/mmbr.00040-16] [Citation(s) in RCA: 117] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Phosphoribosyl diphosphate (PRPP) is an important intermediate in cellular metabolism. PRPP is synthesized by PRPP synthase, as follows: ribose 5-phosphate + ATP → PRPP + AMP. PRPP is ubiquitously found in living organisms and is used in substitution reactions with the formation of glycosidic bonds. PRPP is utilized in the biosynthesis of purine and pyrimidine nucleotides, the amino acids histidine and tryptophan, the cofactors NAD and tetrahydromethanopterin, arabinosyl monophosphodecaprenol, and certain aminoglycoside antibiotics. The participation of PRPP in each of these metabolic pathways is reviewed. Central to the metabolism of PRPP is PRPP synthase, which has been studied from all kingdoms of life by classical mechanistic procedures. The results of these analyses are unified with recent progress in molecular enzymology and the elucidation of the three-dimensional structures of PRPP synthases from eubacteria, archaea, and humans. The structures and mechanisms of catalysis of the five diphosphoryltransferases are compared, as are those of selected enzymes of diphosphoryl transfer, phosphoryl transfer, and nucleotidyl transfer reactions. PRPP is used as a substrate by a large number phosphoribosyltransferases. The protein structures and reaction mechanisms of these phosphoribosyltransferases vary and demonstrate the versatility of PRPP as an intermediate in cellular physiology. PRPP synthases appear to have originated from a phosphoribosyltransferase during evolution, as demonstrated by phylogenetic analysis. PRPP, furthermore, is an effector molecule of purine and pyrimidine nucleotide biosynthesis, either by binding to PurR or PyrR regulatory proteins or as an allosteric activator of carbamoylphosphate synthetase. Genetic analyses have disclosed a number of mutants altered in the PRPP synthase-specifying genes in humans as well as bacterial species.
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18
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Mehra R, Rani C, Mahajan P, Vishwakarma RA, Khan IA, Nargotra A. Computationally Guided Identification of Novel Mycobacterium tuberculosis GlmU Inhibitory Leads, Their Optimization, and in Vitro Validation. ACS COMBINATORIAL SCIENCE 2016; 18:100-16. [PMID: 26812086 DOI: 10.1021/acscombsci.5b00019] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Mycobacterium tuberculosis (Mtb) infections are causing serious health concerns worldwide. Antituberculosis drug resistance threatens the current therapies and causes further need to develop effective antituberculosis therapy. GlmU represents an interesting target for developing novel Mtb drug candidates. It is a bifunctional acetyltransferase/uridyltransferase enzyme that catalyzes the biosynthesis of UDP-N-acetyl-glucosamine (UDP-GlcNAc) from glucosamine-1-phosphate (GlcN-1-P). UDP-GlcNAc is a substrate for the biosynthesis of lipopolysaccharide and peptidoglycan that are constituents of the bacterial cell wall. In the current study, structure and ligand based computational models were developed and rationally applied to screen a drug-like compound repository of 20,000 compounds procured from ChemBridge DIVERSet database for the identification of probable inhibitors of Mtb GlmU. The in vitro evaluation of the in silico identified inhibitor candidates resulted in the identification of 15 inhibitory leads of this target. Literature search of these leads through SciFinder and their similarity analysis with the PubChem training data set (AID 1376) revealed the structural novelty of these hits with respect to Mtb GlmU. IC50 of the most potent identified inhibitory lead (5810599) was found to be 9.018 ± 0.04 μM. Molecular dynamics (MD) simulation of this inhibitory lead (5810599) in complex with protein affirms the stability of the lead within the binding pocket and also emphasizes on the key interactive residues for further designing. Binding site analysis of the acetyltransferase pocket with respect to the identified structural moieties provides a thorough analysis for carrying out the lead optimization studies.
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Affiliation(s)
- Rukmankesh Mehra
- Discovery
Informatics, CSIR-Indian Institute of Integrative Medicine, Canal Road, Jammu 180001, India
| | - Chitra Rani
- Clinical
Microbiology, CSIR-Indian Institute of Integrative Medicine, Canal Road, Jammu 180001, India
- Academy
of Scientific and Innovative Research, CSIR-Indian Institute of Integrative Medicine, Canal Road, Jammu 180001, India
| | - Priya Mahajan
- Discovery
Informatics, CSIR-Indian Institute of Integrative Medicine, Canal Road, Jammu 180001, India
- Academy
of Scientific and Innovative Research, CSIR-Indian Institute of Integrative Medicine, Canal Road, Jammu 180001, India
| | - Ram Ashrey Vishwakarma
- Discovery
Informatics, CSIR-Indian Institute of Integrative Medicine, Canal Road, Jammu 180001, India
| | - Inshad Ali Khan
- Clinical
Microbiology, CSIR-Indian Institute of Integrative Medicine, Canal Road, Jammu 180001, India
- Academy
of Scientific and Innovative Research, CSIR-Indian Institute of Integrative Medicine, Canal Road, Jammu 180001, India
| | - Amit Nargotra
- Discovery
Informatics, CSIR-Indian Institute of Integrative Medicine, Canal Road, Jammu 180001, India
- Academy
of Scientific and Innovative Research, CSIR-Indian Institute of Integrative Medicine, Canal Road, Jammu 180001, India
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19
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Soni V, Suryadevara P, Sriram D, Kumar S, Nandicoori VK, Yogeeswari P. Structure-based design of diverse inhibitors of Mycobacterium tuberculosis N-acetylglucosamine-1-phosphate uridyltransferase: combined molecular docking, dynamic simulation, and biological activity. J Mol Model 2015; 21:174. [PMID: 26078037 DOI: 10.1007/s00894-015-2704-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Accepted: 05/17/2015] [Indexed: 10/23/2022]
Abstract
Persistent nature of Mycobacterium tuberculosis is one of the major factors which make the drug development process monotonous against this organism. The highly lipophilic cell wall, which constituting outer mycolic acid and inner peptidoglycan layers, acts as a barrier for the drugs to enter the bacteria. The rigidity of the cell wall is imparted by the peptidoglycan layer, which is covalently linked to mycolic acid by arabinogalactan. Uridine diphosphate-N-acetylglucosamine (UDP-GlcNAc) serves as the starting material in the biosynthesis of this peptidoglycan layers. This UDP-GlcNAc is synthesized by N-acetylglucosamine-1-phosphate uridyltransferase (GlmU(Mtb)), a bi-functional enzyme with two functional sites, acetyltransferase site and uridyltransferase site. Here, we report design and screening of nine inhibitors against UTP and NAcGlc-1-P of uridyltransferase active site of glmU(Mtb). Compound 4 was showing good inhibition and was selected for further analysis. The isothermal titration calorimetry (ITC) experiments showed the binding energy pattern of compound 4 to the uridyltransferase active site is similar to that of substrate UTP. In silico molecular dynamics (MD) simulation studies, for compound 4, carried out for 10 ns showed the protein-compound complex to be stable throughout the simulation with relative rmsd in acceptable range. Hence, these compounds can serve as a starting point in the drug discovery processes against Mycobacterium tuberculosis.
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Affiliation(s)
- Vijay Soni
- Department of Pharmacy, Birla Institute of Technology & Science-Pilani, Hyderabad campus, Shameerpet, Jawahar Nagar, R.R. District, India
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20
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Ngo A, Fong KT, Cox DL, Chen X, Fisher AJ. Structures of Bacteroides fragilis uridine 5'-diphosphate-N-acetylglucosamine (UDP-GlcNAc) acyltransferase (BfLpxA). ACTA CRYSTALLOGRAPHICA. SECTION D, BIOLOGICAL CRYSTALLOGRAPHY 2015; 71:1068-76. [PMID: 25945572 PMCID: PMC4427197 DOI: 10.1107/s1399004715003326] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2015] [Accepted: 02/16/2015] [Indexed: 11/11/2022]
Abstract
Uridine 5'-diphosphate-N-acetylglucosamine (UDP-GlcNAc) acyltransferase (LpxA) catalyzes a reversible reaction for adding an O-acyl group to the GlcNAc in UDP-GlcNAc in the first step of lipid A biosynthesis. Lipid A constitutes a major component of lipopolysaccharides, also referred to as endotoxins, which form the outer monolayer of the outer membrane of Gram-negative bacteria. Ligand-free and UDP-GlcNAc-bound crystal structures of LpxA from Bacteroides fragilis NCTC 9343, the most common pathogenic bacteria found in abdominal abscesses, have been determined and are presented here. The enzyme crystallizes in a cubic space group, with the crystallographic threefold axis generating the biological functional homotrimer and with each monomer forming a nine-rung left-handed β-helical (LβH) fold in the N-terminus followed by an α-helical motif in the C-terminus. The structure is highly similar to LpxA from other organisms. Yet, despite sharing a similar LβH structure with LpxAs from Escherichia coli and others, previously unseen calcium ions are observed on the threefold axis in B. fragilis LpxA to help stabilize the trimeric assembly.
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Affiliation(s)
- Alice Ngo
- Department of Chemistry, University of California, One Shields Avenue, Davis, CA 95616, USA
| | - Kai T. Fong
- Department of Chemistry, University of California, One Shields Avenue, Davis, CA 95616, USA
| | - Daniel L. Cox
- Department of Physics, University of California, One Shields Avenue, Davis, CA 95616, USA
| | - Xi Chen
- Department of Chemistry, University of California, One Shields Avenue, Davis, CA 95616, USA
| | - Andrew J. Fisher
- Department of Chemistry, University of California, One Shields Avenue, Davis, CA 95616, USA
- Department of Molecular and Cellular Biology, University of California, One Shields Avenue, Davis, CA 95616, USA
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21
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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: 133] [Impact Index Per Article: 14.8] [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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22
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Renner-Schneck M, Hinderberger I, Gisin J, Exner T, Mayer C, Stehle T. Crystal Structure of the N-Acetylmuramic Acid α-1-Phosphate (MurNAc-α1-P) Uridylyltransferase MurU, a Minimal Sugar Nucleotidyltransferase and Potential Drug Target Enzyme in Gram-negative Pathogens. J Biol Chem 2015; 290:10804-13. [PMID: 25767118 DOI: 10.1074/jbc.m114.620989] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Indexed: 11/06/2022] Open
Abstract
The N-acetylmuramic acid α-1-phosphate (MurNAc-α1-P) uridylyltransferase MurU catalyzes the synthesis of uridine diphosphate (UDP)-MurNAc, a crucial precursor of the bacterial peptidoglycan cell wall. MurU is part of a recently identified cell wall recycling pathway in Gram-negative bacteria that bypasses the general de novo biosynthesis of UDP-MurNAc and contributes to high intrinsic resistance to the antibiotic fosfomycin, which targets UDP-MurNAc de novo biosynthesis. To provide insights into substrate binding and specificity, we solved crystal structures of MurU of Pseudomonas putida in native and ligand-bound states at high resolution. With the help of these structures, critical enzyme-substrate interactions were identified that enable tight binding of MurNAc-α1-P to the active site of MurU. The MurU structures define a "minimal domain" required for general nucleotidyltransferase activity. They furthermore provide a structural basis for the chemical design of inhibitors of MurU that could serve as novel drugs in combination therapy against multidrug-resistant Gram-negative pathogens.
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Affiliation(s)
| | - Isabel Hinderberger
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen (IMIT), Department of Biology, and
| | - Jonathan Gisin
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen (IMIT), Department of Biology, and
| | - Thomas Exner
- Institute of Pharmacy, University of Tübingen, 72076 Tübingen, Germany
| | - Christoph Mayer
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen (IMIT), Department of Biology, and
| | - Thilo Stehle
- From the Interfaculty Institute of Biochemistry (IFIB),
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23
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Purification and biochemical characterisation of GlmU from Yersinia pestis. Arch Microbiol 2014; 197:371-8. [PMID: 25417006 DOI: 10.1007/s00203-014-1065-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Revised: 11/12/2014] [Accepted: 11/16/2014] [Indexed: 12/22/2022]
Abstract
Antibiotic resistance has emerged as a real threat to mankind, rendering many compounds ineffective in the fight against bacterial infection, including for significant diseases such as plague caused by Yersinia pestis. Essential genes have been identified as promising targets for inhibiting with new classes of compounds. Previously, the gene encoding the bifunctional UDP-N-acetylglucosamine pyrophosphorylase/glucosamine-1-phosphate N-acetyltransferase enzyme GlmU was confirmed as an essential gene in Yersinia. As a step towards exploiting this target for antimicrobial screening, we undertook a biochemical characterisation of the Yersinia GlmU. Effects of pH and magnesium concentration on the acetyltransferase and uridyltransferase activities were analysed, and kinetic parameters were determined. The acetyltransferase activity, which is strongly increased in the presence of reducing agent, was shown to be susceptible to oxidation and thiol-specific reagents.
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24
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Vithani N, Bais V, Prakash B. GlmU (N-acetylglucosamine-1-phosphate uridyltransferase) bound to three magnesium ions and ATP at the active site. Acta Crystallogr F Struct Biol Commun 2014; 70:703-8. [PMID: 24915076 PMCID: PMC4051520 DOI: 10.1107/s2053230x14008279] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Accepted: 04/12/2014] [Indexed: 11/10/2022] Open
Abstract
N-Acetylglucosamine-1-phosphate uridyltransferase (GlmU), a bifunctional enzyme exclusive to prokaryotes, belongs to the family of sugar nucleotidyltransferases (SNTs). The enzyme binds GlcNAc-1-P and UTP, and catalyzes a uridyltransfer reaction to synthesize UDP-GlcNAc, an important precursor for cell-wall biosynthesis. As many SNTs are known to utilize a broad range of substrates, substrate specificity in GlmU was probed using biochemical and structural studies. The enzymatic assays reported here demonstrate that GlmU is specific for its natural substrates UTP and GlcNAc-1-P. The crystal structure of GlmU bound to ATP and GlcNAc-1-P provides molecular details for the inability of the enzyme to utilize ATP for the nucleotidyltransfer reaction. ATP binding results in an inactive pre-catalytic enzyme-substrate complex, where it adopts an unusual conformation such that the reaction cannot be catalyzed; here, ATP is shown to be bound together with three Mg2+ ions. Overall, this structure represents the binding of an inhibitory molecule at the active site and can potentially be used to develop new inhibitors of the enzyme. Further, similar to DNA/RNA polymerases, GlmU was recently recognized to utilize two metal ions, MgA2+ and MgB2+, to catalyze the uridyltransfer reaction. Interestingly, displacement of MgB2+ from its usual catalytically competent position, as noted in the crystal structure of RNA polymerase in an inactive state, was considered to be a key factor inhibiting the reaction. Surprisingly, in the current structure of GlmU MgB2+ is similarly displaced; this raises the possibility that an analogous inhibitory mechanism may be operative in GlmU.
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Affiliation(s)
- Neha Vithani
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208 016, India
| | - Vaibhav Bais
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208 016, India
| | - Balaji Prakash
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208 016, India
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