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Deng WH, Liao RZ. Cysteine Radical and Glutamate Collaboratively Enable C-H Bond Activation and C-N Bond Cleavage in a Glycyl Radical Enzyme HplG. J Chem Inf Model 2024; 64:4168-4179. [PMID: 38745447 DOI: 10.1021/acs.jcim.4c00122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Hydroxyprolines are abundant in nature and widely utilized by many living organisms. Isomerization of trans-4-hydroxy-d-proline (t4D-HP) to generate 2-amino-4-ketopentanoate has been found to need a glycyl radical enzyme HplG, which catalyzes the cleavage of the C-N bond, while dehydration of trans-4-hydroxy-l-proline involves a homologous enzyme of HplG. Herein, molecular dynamics simulations and quantum mechanics/molecular mechanics (QM/MM) calculations are employed to understand the reaction mechanism of HplG. Two possible reaction pathways of HplG have been explored to decipher the origin of its chemoselectivity. The QM/MM calculations reveal that the isomerization proceeds via an initial hydrogen shift from the Cγ site of t4D-HP to a catalytic cysteine radical, followed by cleavage of the Cδ-N bond in t4D-HP to form a radical intermediate that captures a hydrogen atom from the cysteine. Activation of the Cδ-H bond in t4D-HP to bring about dehydration of t4D-HP possesses an extremely high energy barrier, thus rendering the dehydration pathway implausible in HplG. On the basis of the current calculations, conserved residue Glu429 plays a pivotal role in the isomerization pathway: the hydrogen bonding between it and t4D-HP weakens the hydroxyalkyl Cγ-Hγ bond, and it acts as a proton acceptor to trigger the cleavage of the C-N bond in t4D-HP. Our current QM/MM calculations rationalize the origin of the experimentally observed chemoselectivity of HplG and propose an H-bond-assisted bond activation strategy in radical-containing enzymes. These findings have general implications on radical-mediated enzymatic catalysis and expand our understanding of how nature wisely and selectively activates the C-H bond to modulate catalytic selectivity.
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Affiliation(s)
- Wen-Hao Deng
- Key Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education, Hubei Key Laboratory of Bioinorganic Chemistry and Materia Medica, Hubei Key Laboratory of Materials Chemistry and Service Failure, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Rong-Zhen Liao
- Key Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education, Hubei Key Laboratory of Bioinorganic Chemistry and Materia Medica, Hubei Key Laboratory of Materials Chemistry and Service Failure, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
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2
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Niu Z, Lei P, Wang Y, Wang J, Yang J, Zhang J. Small molecule LpxC inhibitors against gram-negative bacteria: Advances and future perspectives. Eur J Med Chem 2023; 253:115326. [PMID: 37023679 DOI: 10.1016/j.ejmech.2023.115326] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 03/18/2023] [Accepted: 03/28/2023] [Indexed: 04/03/2023]
Abstract
Uridine diphosphate-3-O-(hydroxymyristoyl)-N-acetylglucosamine deacetylase (LpxC) is a metalloenzyme with zinc ions as cofactors and is a key enzyme in the essential structural outer membrane lipid A synthesis commitment step of gram-negative bacteria. As LpxC is extremely homologous among different Gram-negative bacteria, it is conserved in almost all gram-negative bacteria, which makes LpxC a promising target. LpxC inhibitors have been reported extensively in recent years, such as PF-5081090 and CHIR-090 were found to have broad-spectrum antibiotic activity against P. aeruginosa and E. coli. They are mainly classified into hydroxamate inhibitors and non-hydroxamate inhibitors based on their structure, but no LpxC inhibitors have been marketed due to safety and activity issues. This review, therefore, focuses on small molecule inhibitors of LpxC against gram-negative pathogenic bacteria and covers recent advances in LpxC inhibitors, focusing on their structural optimization process, structure-activity relationships, and future directions, with the aim of providing ideas for the development of LpxC inhibitors and clinical research.
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Dewachter L, Brooks AN, Noon K, Cialek C, Clark-ElSayed A, Schalck T, Krishnamurthy N, Versées W, Vranken W, Michiels J. Deep mutational scanning of essential bacterial proteins can guide antibiotic development. Nat Commun 2023; 14:241. [PMID: 36646716 PMCID: PMC9842644 DOI: 10.1038/s41467-023-35940-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 01/09/2023] [Indexed: 01/18/2023] Open
Abstract
Deep mutational scanning is a powerful approach to investigate a wide variety of research questions including protein function and stability. Here, we perform deep mutational scanning on three essential E. coli proteins (FabZ, LpxC and MurA) involved in cell envelope synthesis using high-throughput CRISPR genome editing, and study the effect of the mutations in their original genomic context. We use more than 17,000 variants of the proteins to interrogate protein function and the importance of individual amino acids in supporting viability. Additionally, we exploit these libraries to study resistance development against antimicrobial compounds that target the selected proteins. Among the three proteins studied, MurA seems to be the superior antimicrobial target due to its low mutational flexibility, which decreases the chance of acquiring resistance-conferring mutations that simultaneously preserve MurA function. Additionally, we rank anti-LpxC lead compounds for further development, guided by the number of resistance-conferring mutations against each compound. Our results show that deep mutational scanning studies can be used to guide drug development, which we hope will contribute towards the development of novel antimicrobial therapies.
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Affiliation(s)
- Liselot Dewachter
- Centre of Microbial and Plant Genetics, KU Leuven, Leuven, Belgium. .,VIB-KU Leuven Center for Microbiology, Leuven, Belgium.
| | | | | | | | | | - Thomas Schalck
- Centre of Microbial and Plant Genetics, KU Leuven, Leuven, Belgium.,VIB-KU Leuven Center for Microbiology, Leuven, Belgium
| | | | - Wim Versées
- Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium.,VIB-VUB Center for Structural Biology, Brussels, Belgium
| | - Wim Vranken
- Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium.,VIB-VUB Center for Structural Biology, Brussels, Belgium.,Interuniversity Institute of Bioinformatics in Brussels, ULB-VUB, Brussels, Belgium
| | - Jan Michiels
- Centre of Microbial and Plant Genetics, KU Leuven, Leuven, Belgium. .,VIB-KU Leuven Center for Microbiology, Leuven, Belgium.
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4
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Dreger A, Hoff K, Agoglitta O, Bülbül EF, Melesina J, Sippl W, Holl R. Synthesis, biological evaluation, and molecular docking studies of deoxygenated C-glycosides as LpxC inhibitors. Bioorg Chem 2021; 117:105403. [PMID: 34758434 DOI: 10.1016/j.bioorg.2021.105403] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 09/23/2021] [Accepted: 10/02/2021] [Indexed: 11/29/2022]
Abstract
The bacterial deacetylase LpxC is a promising target for the development of novel antibiotics being selectively active against Gram-negative bacteria. In chiral pool syntheses starting from d- and l-ribose, a series regio- and stereoisomeric monohydroxytetrahydrofuran derivatives was synthesized and tested for LpxC inhibitory and antibacterial activities. Molecular docking studies were performed to rationalize the obtained structure-activity relationships. The (2S,3R,5R)-configured 3-hydroxytetrahydrofuran derivative ent-8 ((2S,3R,5R)-N,3-Dihydroxy-5-(4-{[4-(morpholinomethyl)phenyl]ethynyl}phenyl)tetrahydrofuran-2-carboxamide) was found to be the most potent LpxC inhibitor (Ki = 3.5 µM) of the synthesized series of monohydroxytetrahydrofuran derivatives and to exhibit the highest antibacterial activity against E. coli BL21(DE3) and the D22 strain.
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Affiliation(s)
- Alexander Dreger
- Institute of Organic Chemistry, University of Hamburg, Martin-Luther-King-Platz 6, 20146 Hamburg, Germany; German Center for Infection Research (DZIF), Partner Site Hamburg-Lübeck-Borstel-Riems, Germany
| | - Katharina Hoff
- Institute of Organic Chemistry, University of Hamburg, Martin-Luther-King-Platz 6, 20146 Hamburg, Germany; German Center for Infection Research (DZIF), Partner Site Hamburg-Lübeck-Borstel-Riems, Germany
| | - Oriana Agoglitta
- Institute of Organic Chemistry, University of Hamburg, Martin-Luther-King-Platz 6, 20146 Hamburg, Germany; German Center for Infection Research (DZIF), Partner Site Hamburg-Lübeck-Borstel-Riems, Germany
| | - Emre F Bülbül
- Institute of Pharmacy, Martin-Luther-University of Halle-Wittenberg, Kurt-Mothes-Str. 3, 06120 Halle (Saale), Germany
| | - Jelena Melesina
- Institute of Pharmacy, Martin-Luther-University of Halle-Wittenberg, Kurt-Mothes-Str. 3, 06120 Halle (Saale), Germany
| | - Wolfgang Sippl
- Institute of Pharmacy, Martin-Luther-University of Halle-Wittenberg, Kurt-Mothes-Str. 3, 06120 Halle (Saale), Germany
| | - Ralph Holl
- Institute of Organic Chemistry, University of Hamburg, Martin-Luther-King-Platz 6, 20146 Hamburg, Germany; German Center for Infection Research (DZIF), Partner Site Hamburg-Lübeck-Borstel-Riems, Germany.
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5
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Antibacterial activity of xylose-derived LpxC inhibitors - Synthesis, biological evaluation and molecular docking studies. Bioorg Chem 2020; 107:104603. [PMID: 33429229 DOI: 10.1016/j.bioorg.2020.104603] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Accepted: 12/24/2020] [Indexed: 12/15/2022]
Abstract
LpxC inhibitors represent a promising class of novel antibiotics selectively combating Gram-negative bacteria. In chiral pool syntheses starting from D- and L-xylose, a series of four 2r,3c,4t-configured C-furanosidic LpxC inhibitors was obtained. The synthesized hydroxamic acids were tested for antibacterial and LpxC inhibitory activity, the acquired biological data were compared with those of previously synthesized C-furanosides, and molecular docking studies were performed to rationalize the observed structure-activity relationships. Additionally, bacterial uptake and susceptibility to efflux pump systems were investigated for the most promising stereoisomers.
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6
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Theoretical Study of VX Hydrolysis Mechanism Catalyzed by Phosphotriesterase Mutant H254R. ChemistrySelect 2020. [DOI: 10.1002/slct.202002112] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Yan J, Chen S. How To Produce Methane Precursor in the Upper Ocean by An Untypical Non‐Heme Fe‐Dependent Methylphosphonate Synthase? Chemphyschem 2020; 21:385-396. [DOI: 10.1002/cphc.202000025] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Indexed: 12/19/2022]
Affiliation(s)
- Ji‐Fan Yan
- Key Laboratory of Cluster Science of Ministry of Education School of Chemistry and Chemical Engineering Beijing Institute of Technology Beijing 100081 China
| | - Shi‐Lu Chen
- Key Laboratory of Cluster Science of Ministry of Education School of Chemistry and Chemical Engineering Beijing Institute of Technology Beijing 100081 China
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8
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Yu MJ, Wu J, Chen SL. Mechanism and Inhibitor Exploration with Binuclear Mg Ketol-Acid Reductoisomerase: Targeting the Biosynthetic Pathway of Branched-Chain Amino Acids. Chembiochem 2019; 21:381-391. [PMID: 31309701 DOI: 10.1002/cbic.201900363] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2019] [Indexed: 01/01/2023]
Abstract
Binuclear Mg ketol-acid reductoisomerase (KARI), which converts (S)-2-acetolactate into (R)-2,3-dihydroxyisovalerate, is responsible for the second step of the biosynthesis of branched-chain amino acids in plants and microorganisms and thus serves as a key inhibition target potentially without effects on mammals. Here, through the use of density functional calculations and a chemical model, the KARI-catalyzed reaction has been demonstrated to include the initial deprotonation of the substrate C2 hydroxy group, bridged by the two Mg ions, alkyl migration from the C2-alkoxide carbon atom to the C3-carbonyl carbon atom, and hydride transfer from a nicotinamide adenine dinucleotide phosphate [NAD(P)H] cofactor to C2. A dead-end mechanism with a hydride transferred to the C3 carbonyl group has been ruled out. The nucleophilicity (migratory aptitude) of the migrating carbon atom and the provision of additional negative charge to the di-Mg coordination sphere have significant effects on the steps of alkyl migration and hydride transfer, respectively. Other important mechanistic characteristics are also revealed. Inspired by the mechanism, an inhibitor (2-carboxylate-lactic acid) was designed and predicted by barrier analysis to be effective in inactivating KARI, hence probably enriching the antifungal and antibacterial library. Two types of slow substrate analogues (2-trihalomethyl acetolactic acids and 2-glutaryl lactic acid) were also found.
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Affiliation(s)
- Ming-Jia Yu
- Key Laboratory of Cluster Science of the Ministry of Education, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, 100081, P. R. China
| | - Jue Wu
- Key Laboratory of Cluster Science of the Ministry of Education, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, 100081, P. R. China
| | - Shi-Lu Chen
- Key Laboratory of Cluster Science of the Ministry of Education, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, 100081, P. R. China
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9
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Kalinin DV, Agoglitta O, Van de Vyver H, Melesina J, Wagner S, Riemann B, Schäfers M, Sippl W, Löffler B, Holl R. Proline-based hydroxamates targeting the zinc-dependent deacetylase LpxC: Synthesis, antibacterial properties, and docking studies. Bioorg Med Chem 2019; 27:1997-2018. [DOI: 10.1016/j.bmc.2019.03.056] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2019] [Revised: 03/28/2019] [Accepted: 03/29/2019] [Indexed: 01/05/2023]
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10
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Dreger A, Kharwb O, Agoglitta O, Bülbül EF, Melesina J, Sippl W, Holl R. Chiral Pool Synthesis, Biological Evaluation and Molecular Docking Studies ofC‐Furanosidic LpxC Inhibitors. ChemMedChem 2019; 14:871-886. [DOI: 10.1002/cmdc.201900068] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Indexed: 01/15/2023]
Affiliation(s)
- Alexander Dreger
- Department of Chemistry, Institute of Organic ChemistryUniversity of Hamburg Martin-Luther-King Platz 6 20146 Hamburg Germany
- German Center for Infection Research (DZIF), partner site Hamburg-Lübeck-Borstel-Riems Germany
| | - Omar Kharwb
- Institute of Pharmaceutical and Medicinal ChemistryUniversity of Münster Corrensstr. 48 48149 Münster Germany
| | - Oriana Agoglitta
- Department of Chemistry, Institute of Organic ChemistryUniversity of Hamburg Martin-Luther-King Platz 6 20146 Hamburg Germany
- German Center for Infection Research (DZIF), partner site Hamburg-Lübeck-Borstel-Riems Germany
- NRW Graduate School of ChemistryUniversity of Münster Germany
| | - Emre F. Bülbül
- Institute of PharmacyMartin Luther University of Halle-Wittenberg Wolfgang-Langenbeck Str. 4 06120 Halle/Saale Germany
| | - Jelena Melesina
- Institute of PharmacyMartin Luther University of Halle-Wittenberg Wolfgang-Langenbeck Str. 4 06120 Halle/Saale Germany
| | - Wolfgang Sippl
- Institute of PharmacyMartin Luther University of Halle-Wittenberg Wolfgang-Langenbeck Str. 4 06120 Halle/Saale Germany
| | - Ralph Holl
- Department of Chemistry, Institute of Organic ChemistryUniversity of Hamburg Martin-Luther-King Platz 6 20146 Hamburg Germany
- German Center for Infection Research (DZIF), partner site Hamburg-Lübeck-Borstel-Riems Germany
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11
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3D-QSAR, Molecular Docking and Molecular Dynamics Simulation of Pseudomonas aeruginosa LpxC Inhibitors. Int J Mol Sci 2017; 18:ijms18050761. [PMID: 28481250 PMCID: PMC5454807 DOI: 10.3390/ijms18050761] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2017] [Revised: 03/17/2017] [Accepted: 03/26/2017] [Indexed: 11/17/2022] Open
Abstract
As an important target for the development of novel antibiotics, UDP-3-O-(R-3-hydroxymyristoyl)-N-acetylglucosamine deacetylase (LpxC) has been widely studied. Pyridone methylsulfone hydroxamate (PMH) compounds can effectively inhibit the catalytic activity of LpxC. In this work, the three-dimensional quantitative structure-activity relationships of PMH inhibitors were explored and models with good predictive ability were established using comparative molecular field analysis and comparative molecular similarity index analysis methods. The effect of PMH inhibitors' electrostatic potential on the inhibitory ability of Pseudomonas aeruginosa LpxC (PaLpxC) is revealed at the molecular level via molecular electrostatic potential analyses. Then, two molecular dynamics simulations for the PaLpxC and PaLpxC-inhibitor systems were also performed respectively to investigate the key residues of PaLpxC hydrolase binding to water molecules. The results indicate that orderly alternative water molecules can form stable hydrogen bonds with M62, E77, T190, and H264 in the catalytic center, and tetracoordinate to zinc ion along with H78, H237, and D241. It was found that the conformational transition space of PaLpxC changes after association with PMH inhibitors through free energy landscape and cluster analyses. Finally, a possible inhibitory mechanism of PMH inhibitors was proposed, based on our molecular simulation. This paper will provide a theoretical basis for the molecular design of LpxC-targeting antibiotics.
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12
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Lan CL, Chen SL. The Decarboxylation of α,β-Unsaturated Acid Catalyzed by Prenylated FMN-Dependent Ferulic Acid Decarboxylase and the Enzyme Inhibition. J Org Chem 2016; 81:9289-9295. [PMID: 27618344 DOI: 10.1021/acs.joc.6b01872] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ferulic acid decarboxylase (Fdc1) is able to catalyze the decarboxylation of α,β-unsaturated acids using a novel cofactor, prenylated flavin mononucleotide (PrFMN). Using density functional theory calculations, we here have investigated the Fdc1 reaction mechanism with the substrate of α-methylcinnamic acid. It is demonstrated that Fdc1 employs a 1,3-dipolar cycloaddition mechanism involving four concerted steps, where the Glu282 acts as a crucial proton donor to protonate the α carbon (Cα). The last step, the decomposition of a pyrrolidine species, is rate-limiting with an overall barrier of 18.9 kcal mol-1. Furthermore, when α-hydroxycinnamic acid is used, the Glu282 is found to have another face to transport the hydroxyl proton to the Cβ atom to promote the tautomerization from enol intermediate to ketone species leading to the inhibition of the Fdc1 enzyme. The PrFMN roles are also discussed in detail.
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Affiliation(s)
- Cui-Lan Lan
- Key Laboratory of Cluster Science of Ministry of Education, School of Chemistry and Chemical Engineering, Beijing Institute of Technology , Beijing 100081, China
| | - Shi-Lu Chen
- Key Laboratory of Cluster Science of Ministry of Education, School of Chemistry and Chemical Engineering, Beijing Institute of Technology , Beijing 100081, China
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13
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Ion BF, Kazim E, Gauld JW. A multi-scale computational study on the mechanism of Streptococcus pneumoniae Nicotinamidase (SpNic). Molecules 2014; 19:15735-53. [PMID: 25268724 PMCID: PMC6271260 DOI: 10.3390/molecules191015735] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Revised: 09/20/2014] [Accepted: 09/22/2014] [Indexed: 11/16/2022] Open
Abstract
Nicotinamidase (Nic) is a key zinc-dependent enzyme in NAD metabolism that catalyzes the hydrolysis of nicotinamide to give nicotinic acid. A multi-scale computational approach has been used to investigate the catalytic mechanism, substrate binding and roles of active site residues of Nic from Streptococcus pneumoniae (SpNic). In particular, density functional theory (DFT), molecular dynamics (MD) and ONIOM quantum mechanics/molecular mechanics (QM/MM) methods have been employed. The overall mechanism occurs in two stages: (i) formation of a thioester enzyme-intermediate (IC2) and (ii) hydrolysis of the thioester bond to give the products. The polar protein environment has a significant effect in stabilizing reaction intermediates and in particular transition states. As a result, both stages effectively occur in one step with Stage 1, formation of IC2, being rate limiting barrier with a cost of 53.5 kJ·mol-1 with respect to the reactant complex, RC. The effects of dispersion interactions on the overall mechanism were also considered but were generally calculated to have less significant effects with the overall mechanism being unchanged. In addition, the active site lysyl (Lys103) is concluded to likely play a role in stabilizing the thiolate of Cys136 during the reaction.
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Affiliation(s)
- Bogdan F Ion
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, ON N9B 3P4, Canada
| | - Erum Kazim
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, ON N9B 3P4, Canada
| | - James W Gauld
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, ON N9B 3P4, Canada.
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Schitter G, Wrodnigg TM. Update on carbohydrate-containing antibacterial agents. Expert Opin Drug Discov 2013; 4:315-56. [PMID: 23489128 DOI: 10.1517/17460440902778725] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Since the first known use of antibiotics > 2,500 years ago, a research field with immense importance for the welfare of mankind has been developed. After a decrease in interest in this topic by the end of the 20th century the occurrence of (poly-)resistant strains of bacteria induced a revival of antibiotics research. Health systems have been seeking viable and reliable solutions to this dangerous and expansive threat. OBJECTIVE This review will focus on carbohydrate-containing antibiotics and will give an outline of recently published novel isolated, semisynthetic as well as synthetic structures, their mechanism of action, if known, and the strategies for the design of compounds with potential by improved antibacterial properties. METHODS The literature between 2000 and 2008 was screened with main focus on recent examples of novel structures and strategies for the lead finding of exclusively antibacterial agents. RESULTS/CONCLUSION With the explanation of the role of the carbohydrate moieties in the respective antibacterial agents together with better synthetic strategies in carbohydrate chemistry as well as improvements in assay development for high throughput screening methods, carbohydrate-containing antibiotics can be used for the finding of potential drug leads that contribute to the fight against infections and diseases caused by (resistant) bacterial pathogens.
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Affiliation(s)
- Georg Schitter
- Technical University Graz, Institute of Organic Chemistry, Univ.-Doz. TMW, Dip.-Ing. GS, Glycogroup, A-8010 Graz, Austria +43 316 873 8744 ; +43 316 873 8740 ;
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15
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Bushnell EAC, Gauld JW. An assessment of pure, hybrid, meta, and hybrid-meta GGA density functional theory methods for open-shell systems: The case of the nonheme iron enzyme 8R-LOX. J Comput Chem 2012; 34:141-8. [DOI: 10.1002/jcc.23114] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Revised: 08/13/2012] [Accepted: 08/19/2012] [Indexed: 11/06/2022]
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16
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Huang W, Llano J, Gauld JW. Redox mechanism of glycosidic bond hydrolysis catalyzed by 6-phospho-alpha-glucosidase: a DFT study. J Phys Chem B 2010; 114:11196-206. [PMID: 20698522 DOI: 10.1021/jp102399h] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Glycosidic bonds are remarkably resistant to cleavage by chemical hydrolysis. Glycoside hydrolases catalyze their selective hydrolysis in oligosaccharides, polysaccharides, and glycoconjugates by following nonredox catalytic pathways or a net redox-neutral catalytic pathway using NAD(+) and divalent metal ions as cofactors. GlvA (6-phospho-alpha-glucosidase) is a glycosidase belonging to family GH4 and follows a regioselective redox-neutral mechanism of glycosidic-bond hydrolysis that favors alpha- over beta-glycosides. Its proposed catalytic mechanism can be divided into two half-reactions: the first one activates the glucopyranose ring by successively forming intermediates that are oxidized at the 3-, 2-, and 1-positions of the ring, which ultimately facilitate the heterolytic deglycosylation. The second half-reaction is essentially the reverse of the first half-reaction, beginning with the pyranose ring hydroxylation at the anomeric carbon, and it is followed by 3-reduction and regeneration of the active forms of the catalytic site and its cofactors. We investigated the NAD(+)-dependent redox mechanism of glycosidic bond hydrolysis as catalyzed by GlvA through the combined application of density functional theory and a self-consistent reaction field to a large active-site model obtained from the crystallographic structure of the enzyme, then we applied natural bond orbital and second-order perturbation analyses to monitor the electron flow and change in oxidation state on each atomic center along the reaction coordinate to rationalize the energetics and regioselectivity of this catalytic mechanism. We find that in GlvA, the redox catalytic mechanism of hydrolysis is driven by the gradual strengthening of the axial endo-anomeric component within the hexose ring along the reaction coordinate to facilitate the heterolytic dissociation of the axial C1-O bond. In addition, the combined influence of specific components of the generalized anomeric effect fully explains the regioselectivity observed in the catalytic activity of GlvA.
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Affiliation(s)
- Wenjuan Huang
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario N9B 3P4, Canada
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Hernick M, Gattis SG, Penner-Hahn JE, Fierke CA. Activation of Escherichia coli UDP-3-O-[(R)-3-hydroxymyristoyl]-N-acetylglucosamine deacetylase by Fe2+ yields a more efficient enzyme with altered ligand affinity. Biochemistry 2010; 49:2246-55. [PMID: 20136146 DOI: 10.1021/bi902066t] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The metal-dependent deacetylase UDP-3-O-[(R)-3-hydroxymyristoyl]-N-acetylglucosamine deacetylase (LpxC) catalyzes the first committed step in lipid A biosynthesis, the hydrolysis of UDP-3-O-myristoyl-N-acetylglucosamine to form UDP-3-O-myristoylglucosamine and acetate. Consequently, LpxC is a target for the development of antibiotics, nearly all of which coordinate the active site metal ion. Here we examine the ability of Fe(2+) to serve as a cofactor for wild-type Escherichia coli LpxC and a mutant enzyme (EcC63A), in which one of the ligands for the inhibitory metal binding site has been removed. LpxC exhibits higher activity (6-8-fold) with a single bound Fe(2+) as the cofactor compared to Zn(2+)-LpxC; both metalloenzymes have a bell-shaped dependence on pH with similar pK(a) values, indicating that at least two ionizations are important for maximal activity. X-ray absorption spectroscopy experiments suggest that the catalytic metal ion bound to Fe(2+)-EcLpxC is five-coordinate, suggesting that catalytic activity may correlate with coordination number. Furthermore, the ligand affinity of Fe(2+)-LpxC compared to the Zn(2+) enzyme is altered by up to 6-fold. In contrast to Zn(2+)-LpxC, the activity of Fe(2+)-LpxC is redox-sensitive, and a time-dependent decrease in activity is observed under aerobic conditions. The LpxC activity of crude E. coli cell lysates is also aerobically sensitive, consistent with the presence of Fe(2+)-LpxC. These data indicate that EcLpxC can use either Fe(2+) or Zn(2+) to activate catalysis in vitro and possibly in vivo, which may allow LpxC to function in E. coli grown under different environmental conditions.
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Affiliation(s)
- Marcy Hernick
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA
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Liu H, Llano J, Gauld JW. A DFT study of nucleobase dealkylation by the DNA repair enzyme AlkB. J Phys Chem B 2009; 113:4887-98. [PMID: 19338370 DOI: 10.1021/jp810715t] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Oxidative dealkylation is a unique mechanistic pathway found in the alpha-ketoglutarate-Fe(II)-dependent AlkB family of enzymes to remove the alkylation damage to DNA bases and regenerate nucleobases to their native state. The B3LYP density functional combined with a self-consistent reaction field was used to explore the triplet, quintet, and septet spin-state potential energy surfaces of the multistep catalytic mechanism of AlkB. The mechanism was found to consist of four stages. First, binding of dioxygen to iron in the active-site complex occurs concerted with electron transfer, thereby yielding a ferric-superoxido species. Second, competing initiation for the activation of oxygen to generate the high-valent iron-oxygen intermediates (ferryl-oxo Fe(IV)O and ferric-oxyl Fe(III)O(*) species) was found to occur on the quintet and septet surfaces. Then, conformational reorientation of the activated iron-oxygen ligand was found to be nearly thermoneutral with a barrier of ca. 50 kJ mol(-1). The final stage is the oxidative dealkylation of the damaged nucleobase with the rate-controlling step being the abstraction of a hydrogen atom from the damaging methyl group by the ferryl-oxo ligand. For this step, the calculated barrier of 87.4 kJ mol(-1) is in good agreement with the experimental activation energy of ca. 83 kJ mol(-1) for the enzyme-catalyzed reaction.
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Affiliation(s)
- Haining Liu
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario N9B 3P4, Canada
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A quantum mechanics study on the reaction mechanism of chalcone formation from p-coumaroyl-CoA and malonyl-CoA catalyzed by chalcone synthase. Theor Chem Acc 2008. [DOI: 10.1007/s00214-008-0495-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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