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Mycobacterium tuberculosis Shikimate Pathway Enzymes as Targets for the Rational Design of Anti-Tuberculosis Drugs. Molecules 2020; 25:molecules25061259. [PMID: 32168746 PMCID: PMC7144000 DOI: 10.3390/molecules25061259] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Revised: 02/06/2020] [Accepted: 02/10/2020] [Indexed: 12/17/2022] Open
Abstract
Roughly a third of the world’s population is estimated to have latent Mycobacterium tuberculosis infection, being at risk of developing active tuberculosis (TB) during their lifetime. Given the inefficacy of prophylactic measures and the increase of drug-resistant M. tuberculosis strains, there is a clear and urgent need for the development of new and more efficient chemotherapeutic agents, with selective toxicity, to be implemented on patient treatment. The component enzymes of the shikimate pathway, which is essential in mycobacteria and absent in humans, stand as attractive and potential targets for the development of new drugs to treat TB. This review gives an update on published work on the enzymes of the shikimate pathway and some insight on what can be potentially explored towards selective drug development.
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Dos Santos AM, Lima AH, Alves CN, Lameira J. Unraveling the Addition-Elimination Mechanism of EPSP Synthase through Computer Modeling. J Phys Chem B 2017; 121:8626-8637. [PMID: 28829128 DOI: 10.1021/acs.jpcb.7b05063] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Enolpyruvyl transfer from phosphoenolpyruvate (PEP) to the hydroxyl group of shikimate-5-OH-3-phosphate (S3P) is catalyzed by 5-enolpyruvylshikimate 3-phosphate (EPSP) synthase in a reaction that involves breaking the C-O bond of PEP. Catalysis involves an addition-elimination mechanism with the formation of a tetrahedral intermediate (THI). Experiments have elucidated the mechanism of THI formation and breakdown. However, the catalytic action of EPSP synthase and the individual roles of catalytic residues Asp313 and Glu341 remains unclear. We have used a hybrid quantum mechanical/molecular mechanical (QM/MM) approach to explore the free energy surface in a reaction catalyzed by EPSP synthase. The Glu341 was the most favorable acid/base catalyst. Our results indicate that the protonation of PEP C3 precedes the nucleophilic attack on PEP C2 in the addition mechanism. Also, the breaking of the C-O bond of THI to form an EPSP cation intermediate must occur before proton transfer from PEP C3 to Glu341 in the elimination mechanism. Analysis of the FES supports cationic intermediate formation during the reaction catalyzed by EPSP synthase. Finally, the computational model indicates a proton transfer shift (Hammond shift) from Glu341 to C3 for an enzyme-based reaction with the shifted transition state, earlier than in the reference reaction in water.
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Affiliation(s)
- Alberto M Dos Santos
- Institute of Biological Sciences, Federal University of Pará , Belém, PA 66075-110, Brazil
| | - Anderson H Lima
- Institute of Biological Sciences, Federal University of Pará , Belém, PA 66075-110, Brazil
| | - Cláudio Nahum Alves
- Institute of Exact and Natural Sciences, Federal University of Pará , Belém, PA 66075-110, Brazil
| | - Jerônimo Lameira
- Institute of Biological Sciences, Federal University of Pará , Belém, PA 66075-110, Brazil
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Ancheeva E, Küppers L, Akone SH, Ebrahim W, Liu Z, Mándi A, Kurtán T, Lin W, Orfali R, Rehberg N, Kalscheuer R, Daletos G, Proksch P. Expanding the Metabolic Profile of the FungusChaetomiumsp. through Co-culture with AutoclavedPseudomonas aeruginosa. European J Org Chem 2017. [DOI: 10.1002/ejoc.201700288] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Elena Ancheeva
- Institute of Pharmaceutical Biology and Biotechnology; Heinrich Heine University; Universitätstrasse 1, Geb. 26.23 40225 Düsseldorf Germany
| | - Lisa Küppers
- Institute of Pharmaceutical Biology and Biotechnology; Heinrich Heine University; Universitätstrasse 1, Geb. 26.23 40225 Düsseldorf Germany
| | - Sergi Herve Akone
- Institute of Pharmaceutical Biology and Biotechnology; Heinrich Heine University; Universitätstrasse 1, Geb. 26.23 40225 Düsseldorf Germany
- Faculty of Science; Department of Chemistry; University of Douala; P. O. Box 24157 Douala Cameroon
| | - Weaam Ebrahim
- Institute of Pharmaceutical Biology and Biotechnology; Heinrich Heine University; Universitätstrasse 1, Geb. 26.23 40225 Düsseldorf Germany
- Department of Pharmacognosy; Faculty of Pharmacy; Mansoura University; 35516 Mansoura Egypt
| | - Zhen Liu
- Institute of Pharmaceutical Biology and Biotechnology; Heinrich Heine University; Universitätstrasse 1, Geb. 26.23 40225 Düsseldorf Germany
| | - Attila Mándi
- Department of Organic Chemistry; University of Debrecen; P. O. Box 400 4002 Debrecen Hungary
| | - Tibor Kurtán
- Department of Organic Chemistry; University of Debrecen; P. O. Box 400 4002 Debrecen Hungary
| | - Wenhan Lin
- State Key Laboratory of Natural and Biomimetic Drugs; Peking University; 100191 Beijing China
| | - Raha Orfali
- Department of Pharmacognosy; Faculty of Pharmacy; King Saud University; Riyadh Saudi Arabia
| | - Nidja Rehberg
- Institute of Pharmaceutical Biology and Biotechnology; Heinrich Heine University; Universitätstrasse 1, Geb. 26.23 40225 Düsseldorf Germany
| | - Rainer Kalscheuer
- Institute of Pharmaceutical Biology and Biotechnology; Heinrich Heine University; Universitätstrasse 1, Geb. 26.23 40225 Düsseldorf Germany
| | - Georgios Daletos
- Institute of Pharmaceutical Biology and Biotechnology; Heinrich Heine University; Universitätstrasse 1, Geb. 26.23 40225 Düsseldorf Germany
| | - Peter Proksch
- Institute of Pharmaceutical Biology and Biotechnology; Heinrich Heine University; Universitätstrasse 1, Geb. 26.23 40225 Düsseldorf Germany
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Chang CM, Chern J, Chen MY, Huang KF, Chen CH, Yang YL, Wu SH. Avenaciolides: Potential MurA-Targeted Inhibitors Against Peptidoglycan Biosynthesis in Methicillin-Resistant Staphylococcus aureus (MRSA). J Am Chem Soc 2014; 137:267-75. [DOI: 10.1021/ja510375f] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | | | - Ming-Yi Chen
- General
Education Center, National Taipei University of Nursing and Health Sciences, Taipei 112, Taiwan
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Lou M, Gilpin ME, Burger SK, Malik AM, Gawuga V, Popović V, Capretta A, Berti PJ. Transition state analysis of acid-catalyzed hydrolysis of an enol ether, enolpyruvylshikimate 3-phosphate (EPSP). J Am Chem Soc 2012; 134:12947-57. [PMID: 22765168 DOI: 10.1021/ja3043382] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Proton transfer to carbon represents a significant catalytic challenge because of the large intrinsic energetic barrier and the frequently unfavorable thermodynamics. Multiple kinetic isotope effects (KIEs) were measured for acid-catalyzed hydrolysis of the enol ether functionality of enolpyruvylshikimate 3-phosphate (EPSP) as a nonenzymatic analog of the EPSP synthase (AroA) reaction. The large solvent deuterium KIE demonstrated that protonating C3 was the rate-limiting step, and the lack of solvent hydron exchange into EPSP demonstrated that protonation was irreversible. The reaction mechanism was stepwise, with C3, the methylene carbon, being protonated to form a discrete oxacarbenium ion intermediate before water attack at the cationic center, that is, an AH(‡)*AN (or AH(‡) + AN) mechanism. The calculated 3-(14)C and 3,3-(2)H2 KIEs varied as a function of the extent of proton transfer at the transition state, as reflected in the C3-H(+) bond order, nC3-H+. The calculated 3-(14)C KIE was a function primarily of C3 coupling with the movement of the transferring proton, as reflected in the reaction coordinate contribution ((light)ν(‡)/(heavy)ν(‡)), rather than of changes in bonding. Coupling was strongest in early and late transition states, where the reaction coordinate frequency was lower. The other calculated (14)C and (18)O KIEs were more sensitive to interactions with counterions and solvation in the model structures than nC3-H+. The KIEs revealed a moderately late transition state with significant oxacarbenium ion character and with a C3-H(+) bond order ≈0.6.
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Affiliation(s)
- Meiyan Lou
- Department of Chemistry & Chemical Biology, and †Department of Biochemistry & Biomedical Sciences, McMaster University , 1280 Main Street West, Hamilton, Ontario L8S 4M1, Canada
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Lou M, Burger SK, Gilpin ME, Gawuga V, Capretta A, Berti PJ. Transition State Analysis of Enolpyruvylshikimate 3-Phosphate (EPSP) Synthase (AroA)-Catalyzed EPSP Hydrolysis. J Am Chem Soc 2012; 134:12958-69. [PMID: 22765279 DOI: 10.1021/ja304339h] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Meiyan Lou
- Department of Chemistry & Chemical Biology, and †Department of Biochemistry & Biomedical Sciences, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4M1, Canada
| | - Steven K. Burger
- Department of Chemistry & Chemical Biology, and †Department of Biochemistry & Biomedical Sciences, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4M1, Canada
| | - Meghann E. Gilpin
- Department of Chemistry & Chemical Biology, and †Department of Biochemistry & Biomedical Sciences, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4M1, Canada
| | - Vivian Gawuga
- Department of Chemistry & Chemical Biology, and †Department of Biochemistry & Biomedical Sciences, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4M1, Canada
| | - Alfredo Capretta
- Department of Chemistry & Chemical Biology, and †Department of Biochemistry & Biomedical Sciences, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4M1, Canada
| | - Paul J. Berti
- Department of Chemistry & Chemical Biology, and †Department of Biochemistry & Biomedical Sciences, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4M1, Canada
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Jiang S, Gilpin ME, Attia M, Ting YL, Berti PJ. Lyme disease enolpyruvyl-UDP-GlcNAc synthase: fosfomycin-resistant MurA from Borrelia burgdorferi, a fosfomycin-sensitive mutant, and the catalytic role of the active site Asp. Biochemistry 2011; 50:2205-12. [PMID: 21294548 DOI: 10.1021/bi1017842] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
MurAs (enolpyruvyl-UDP-GlcNAc synthases) from pathogenic bacteria such as Borrelia burgdorferi (Lyme disease) and tuberculosis are fosfomycin resistant because an Asp-for-Cys substitution prevents them from being alkylated by this epoxide antibiotic. Previous attempts to characterize naturally Asp-containing MurAs have resulted in no protein or no activity. We have expressed and characterized His-tagged Lyme disease MurA (Bb_MurA(H6)). The protein was most soluble at high salt concentrations but maximally active around physiological ionic strength. The steady-state kinetic parameters at pH 7 were k(cat) = 1.07 ± 0.03 s(-1), K(M,PEP) = 89 ± 12 μM, and K(M,UDP-GlcNAc) = 45 ± 7 μM. Mutating the active site Asp to Cys, D116C, caused a 21-fold decrease in k(cat) and rendered the enzyme fosfomycin sensitive. The pH profile of k(cat) was bell-shaped and centered around pH 5.3 for Bb_MurA(H6), with pK(a1) = 3.8 ± 0.2 and pK(a2) = 7.4 ± 0.2. There was little change in pK(a1) with the D116C mutant, 3.5 ± 0.3, but pK(a2) shifted to >11. This demonstrated that the pK(a2) of 7.4 was due to D116, almost 3 pH units above an unperturbed carboxylate, and that it must be protonated for activity. This supports D116's proposed role as a general acid/base catalyst. As fosfomycin does not react with simple thiols, nor most protein thiols, the reactivity of D116C with fosfomycin, combined with the strongly perturbed pK(a2) for D116, strongly implies an unusual active site environment and a chemical role in catalysis for Asp/Cys. There is also good evidence for C115 having a role in product release. Both roles may be operative for both Asp- and Cys-containing MurAs.
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Affiliation(s)
- Shan Jiang
- Chemical Biology Graduate Program, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4M1, Canada
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Domínguez de María P, van Gemert RW, Straathof AJJ, Hanefeld U. Biosynthesis of ethers: unusual or common natural events? Nat Prod Rep 2010; 27:370-92. [PMID: 20179877 DOI: 10.1039/b809416k] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Ether bonds are found in a wide variety of natural products--mainly secondary metabolites--including lipids, oxiranes, terpenoids, flavonoids, polyketides, and carbohydrate derivatives, to name some representative examples. To furnish such a biodiversity of structures, a large number of different enzymes are involved in several different biosynthetic pathways. Depending on the compound and on the (micro) environment in which the reaction is performed, ethers are produced by very different (enzymatic) reactions, thus providing an impressive display of how Nature has combined evolution and thermodynamics to be able to produce a vast number of compounds. In addition, many of these compounds possess different biological activities of pharmacological interest. Moreover, some of these ethers (i.e., epoxides) have high chemical reactivity, and can be useful starting materials for further synthetic processes. This review aims to provide an overview of the different strategies that are found in Nature for the formation of these "bioethers". Both fundamental and practical insights of the biosynthetic processes will be discussed.
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Jackson SG, Zhang F, Chindemi P, Junop MS, Berti PJ. Evidence of kinetic control of ligand binding and staged product release in MurA (enolpyruvyl UDP-GlcNAc synthase)-catalyzed reactions . Biochemistry 2010; 48:11715-23. [PMID: 19899805 DOI: 10.1021/bi901524q] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
MurA (enolpyruvyl UDP-GlcNAc synthase) catalyzes the first committed step in peptidoglycan biosynthesis. In this study, MurA-catalyzed breakdown of its tetrahedral intermediate (THI), with a k(cat)/K(M) of 520 M(-1) s(-1), was far slower than the normal reaction, and 3 x 10(5)-fold slower than the homologous enzyme, AroA, reacting with its THI. This provided kinetic evidence of slow binding and a conformationally constrained active site. The MurA cocrystal structure with UDP-N-acetylmuramic acid (UDP-MurNAc), a potent inhibitor, and phosphite revealed a new "staged" MurA conformation in which the Arg397 side chain tracked phosphite out of the catalytic site. The closed-to-staged transition involved breaking eight MurA.ligand ion pairs, and three intraprotein hydrogen bonds helping hold the active site loop closed. These were replaced with only two MurA.UDP-MurNAc ion pairs, two with phosphite, and seven new intraprotein ion pairs or hydrogen bonds. Cys115 appears to have an important role in forming the staged conformation. The staged conformation appears to be one step in a complex choreography of release of the product from MurA.
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Affiliation(s)
- Sean G Jackson
- Department of Biochemistry and Biomedical Sciences, McMaster University, 1280 Main Street West, Hamilton,Ontario L8S 4M1, Canada
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Berti PJ, Chindemi P. Catalytic residues and an electrostatic sandwich that promote enolpyruvyl shikimate 3-phosphate synthase (AroA) catalysis. Biochemistry 2009; 48:3699-707. [PMID: 19271774 DOI: 10.1021/bi802251s] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Enolpyruvylshikimate 3-phosphate synthase (EPSP synthase, AroA) catalyzes the sixth step in aromatic amino acid biosynthesis. It forms EPSP from shikimate 3-phosphate (S3P) and phosphoenolpyruvate (PEP) in an addition/elimination reaction that proceeds through a tetrahedral intermediate. In spite of numerous mechanistic studies, the catalytic roles of specific amino acid residues remain an open question. Recent experimental evidence for cationic intermediates or cationic transition states, and a consideration of the catalytic imperative, have guided this study on the catalytic roles of Lys22 (K22), Asp313 (D313), and Glu341 (E341). Steady-state and pre-steady-state kinetics and protein stability studies showed that mutations of D313 and E341 caused k(cat) to decrease up to 30,000-fold and 76,000-fold, respectively, while the effects on K(M) were modest, never more than 40-fold. Thus, both are identified as catalytic residues. In an active site that is overwhelmingly positively charged, the D313 and E341 side chains are positioned to form an "electrostatic sandwich" around the positive charge at C2 in cationic intermediates/transition states, stabilizing them and thereby promoting catalysis. Mutation of K22 showed large effects on K(M,S3P) (100-fold), K(M,PEP) (>760-fold), and up to 120-fold on k(cat). Thus, K22 had roles in both substrate-binding and transition-state stabilization. These results support the identification of E341 and K22 as general acid/base catalytic residues.
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Affiliation(s)
- Paul J Berti
- Department of Chemistry, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4M1, Canada.
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Abstract
This chapter describes in detail the genes and proteins of Escherichia coli involved in the biosynthesis and transport of the three aromatic amino acids tyrosine, phenylalanine, and tryptophan. It provides a historical perspective on the elaboration of the various reactions of the common pathway converting erythrose-4-phosphate and phosphoenolpyruvate to chorismate and those of the three terminal pathways converting chorismate to phenylalanine, tyrosine, and tryptophan. The regulation of key reactions by feedback inhibition, attenuation, repression, and activation are also discussed. Two regulatory proteins, TrpR (108 amino acids) and TyrR (513 amino acids), play a major role in transcriptional regulation. The TrpR protein functions only as a dimer which, in the presence of tryptophan, represses the expression of trp operon plus four other genes (the TrpR regulon). The TyrR protein, which can function both as a dimer and as a hexamer, regulates the expression of nine genes constituting the TyrR regulon. TyrR can bind each of the three aromatic amino acids and ATP and under their influence can act as a repressor or activator of gene expression. The various domains of this protein involved in binding the aromatic amino acids and ATP, recognizing DNA binding sites, interacting with the alpha subunit of RNA polymerase, and changing from a monomer to a dimer or a hexamer are all described. There is also an analysis of the various strategies which allow TyrR in conjunction with particular amino acids to differentially affect the expression of individual genes of the TyrR regulon.
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de Souza AX, Sant’Anna CMR. 5-Enolpyruvylshikimate-3-phosphate synthase: Determination of the protonation state of active site residues by the semiempirical method. Bioorg Chem 2008; 36:113-20. [DOI: 10.1016/j.bioorg.2007.12.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2007] [Revised: 12/12/2007] [Accepted: 12/27/2007] [Indexed: 10/22/2022]
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