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Venkatesan M, Fruci M, Verellen LA, Skarina T, Mesa N, Flick R, Pham C, Mahadevan R, Stogios PJ, Savchenko A. Molecular mechanism of plasmid-borne resistance to sulfonamide antibiotics. Nat Commun 2023; 14:4031. [PMID: 37419898 PMCID: PMC10328974 DOI: 10.1038/s41467-023-39778-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 06/21/2023] [Indexed: 07/09/2023] Open
Abstract
The sulfonamides (sulfas) are the oldest class of antibacterial drugs and inhibit the bacterial dihydropteroate synthase (DHPS, encoded by folP), through chemical mimicry of its co-substrate p-aminobenzoic acid (pABA). Resistance to sulfa drugs is mediated either by mutations in folP or acquisition of sul genes, which code for sulfa-insensitive, divergent DHPS enzymes. While the molecular basis of resistance through folP mutations is well understood, the mechanisms mediating sul-based resistance have not been investigated in detail. Here, we determine crystal structures of the most common Sul enzyme types (Sul1, Sul2 and Sul3) in multiple ligand-bound states, revealing a substantial reorganization of their pABA-interaction region relative to the corresponding region of DHPS. We use biochemical and biophysical assays, mutational analysis, and in trans complementation of E. coli ΔfolP to show that a Phe-Gly sequence enables the Sul enzymes to discriminate against sulfas while retaining pABA binding and is necessary for broad resistance to sulfonamides. Experimental evolution of E. coli results in a strain harboring a sulfa-resistant DHPS variant that carries a Phe-Gly insertion in its active site, recapitulating this molecular mechanism. We also show that Sul enzymes possess increased active site conformational dynamics relative to DHPS, which could contribute to substrate discrimination. Our results reveal the molecular foundation for Sul-mediated drug resistance and facilitate the potential development of new sulfas less prone to resistance.
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Affiliation(s)
- Meenakshi Venkatesan
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, M5S 1A4, Canada
| | - Michael Fruci
- London Research and Development Centre, Agriculture and Agri-Food Canada, London, ON, N5V 4T3, Canada
- Department of Microbiology and Immunology, Western University, London, ON, N6A 3K7, Canada
| | - Lou Ann Verellen
- London Research and Development Centre, Agriculture and Agri-Food Canada, London, ON, N5V 4T3, Canada
- Department of Microbiology and Immunology, Western University, London, ON, N6A 3K7, Canada
| | - Tatiana Skarina
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, M5S 1A4, Canada
| | - Nathalie Mesa
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, M5S 1A4, Canada
| | - Robert Flick
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, M5S 1A4, Canada
| | - Chester Pham
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, M5S 1A4, Canada
| | - Radhakrishnan Mahadevan
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, M5S 1A4, Canada
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON, M5S 3E2, Canada
| | - Peter J Stogios
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, M5S 1A4, Canada.
- Center for Structural Biology of Infectious Diseases (CSBID), Calgary, AB, Canada.
| | - Alexei Savchenko
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, M5S 1A4, Canada.
- Center for Structural Biology of Infectious Diseases (CSBID), Calgary, AB, Canada.
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, AB, T2N 4N1, Canada.
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2
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Ugwu DI, Eze FU, Ezeorah CJ, Rhyman L, Ramasami P, Tania G, Eze CC, Uzoewulu CP, Ogboo BC, Okpareke OC. Synthesis, Structure, Hirshfeld Surface Analysis, Non-Covalent Interaction, and In Silico Studies of 4-Hydroxy-1-[(4-Nitrophenyl)Sulfonyl]Pyrrolidine-2-Carboxyllic Acid. JOURNAL OF CHEMICAL CRYSTALLOGRAPHY 2023; 53:1-14. [PMID: 37362239 PMCID: PMC9998016 DOI: 10.1007/s10870-023-00978-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Accepted: 02/14/2023] [Indexed: 06/28/2023]
Abstract
The new compound 4-hydroxy-1-[(4-nitrophenyl)sulfonyl]pyrrolidine-2-carboxyllic acid was obtained by the reaction of 4-hydroxyproline with 4-nitrobenzenesulfonyl chloride. The compound was characterized using single crystal X-ray diffraction studies. Spectroscopic methods including NMR, FTIR, ES-MS, and UV were employed for further structural analysis of the synthesized compound. The title compound was found to have crystallized in an orthorhombic crystal system with space group P212121. The S1-N1 bond length of 1.628 (2) Å was a strong indication of the formation of the title compound. The absence of characteristic downfield 1H NMR peak of pyrrolidine ring and the presence of S-N stretching vibration at 857.82 cm-1 on the FTIR are strong indications for the formation of the sulfonamide. The experimental study was complemented with computations at the B3LYP/6-311G + + (d,p) level of theory to gain more understanding of interactions in the compound at the molecular level. Noncovalent interaction, Hirsfeld surface analysis and interaction energy calculations were employed in the analysis of the supramolecular architecture of the compound. Predicted ADMET parameters, awarded suitable bioavailability credentials, while the molecular docking study indicated that the compound enchants promising inhibition prospects against dihydropteroate synthase, DNA topoisomerase, and SARS-CoV-2 spike. Graphical Abstract Herein we present the solid state structure, noncovalent interaction and spectroscopic analysis of a prospective bioactive compound 4-hydroxy-1-[(4-nitrophenyl)sulphonyl]pyrrolidine-2-carboxyllic acid. Supplementary Information The online version contains supplementary material available at 10.1007/s10870-023-00978-0.
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Affiliation(s)
- David Izuchukwu Ugwu
- Department of Pure and Industrial Chemistry, University of Nigeria, Nsukka, 410001 Nigeria
| | - Florence Uchenna Eze
- Department of Pure and Industrial Chemistry, University of Nigeria, Nsukka, 410001 Nigeria
| | - Chigozie Julius Ezeorah
- Department of Pure and Industrial Chemistry, University of Nigeria, Nsukka, 410001 Nigeria
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 29208 USA
| | - Lydia Rhyman
- Computational Chemistry Group, Department of Chemistry, Faculty of Science, University of Mauritius, Réduit, 808037 Mauritius
- Centre for Natural Product Research, Department of Chemical Sciences, University of Johannesburg, Doornfontein, Johannesburg, 2028 South Africa
| | - Ponnadurai Ramasami
- Computational Chemistry Group, Department of Chemistry, Faculty of Science, University of Mauritius, Réduit, 808037 Mauritius
- Centre for Natural Product Research, Department of Chemical Sciences, University of Johannesburg, Doornfontein, Johannesburg, 2028 South Africa
| | - Groutso Tania
- School of Chemical Sciences, University of Auckland, Private Bag 92019, Auckland, 1142 New Zealand
| | - Cosmas Chinweike Eze
- Department of Pure and Industrial Chemistry, University of Nigeria, Nsukka, 410001 Nigeria
- Natural Science Unit, School of General Studies, University of Nigeria, Nsukka, 410001 Nigeria
- Department of Chemistry, North Carolina State University, Raleigh, NC 27695-8204 USA
| | - Chiamaka Peace Uzoewulu
- Department of Pure and Industrial Chemistry, University of Nigeria, Nsukka, 410001 Nigeria
- Department of Chemistry, North Carolina State University, Raleigh, NC 27695-8204 USA
| | - Blessing Chinweotito Ogboo
- Department of Pure and Industrial Chemistry, University of Nigeria, Nsukka, 410001 Nigeria
- Department of Chemistry, State University of NewYork at Buffalo, Buffalo, NY 14260 USA
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3
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Vadlamani G, Sukhoverkov KV, Haywood J, Breese KJ, Fisher MF, Stubbs KA, Bond CS, Mylne JS. Crystal structure of Arabidopsis thaliana HPPK/DHPS, a bifunctional enzyme and target of the herbicide asulam. PLANT COMMUNICATIONS 2022; 3:100322. [PMID: 35605193 PMCID: PMC9284294 DOI: 10.1016/j.xplc.2022.100322] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 03/21/2022] [Accepted: 04/06/2022] [Indexed: 06/15/2023]
Abstract
Herbicides are vital for modern agriculture, but their utility is threatened by genetic or metabolic resistance in weeds, as well as regulatory barriers. Of the known herbicide modes of action, 7,8-dihydropterin synthase (DHPS), which is involved in folate biosynthesis, is targeted by just one commercial herbicide, asulam. A mimic of the substrate para-aminobenzoic acid, asulam is chemically similar to sulfonamide antibiotics, and although it is still in widespread use, asulam has faced regulatory scrutiny. With an entire mode of action represented by just one commercial agrochemical, we sought to improve the understanding of its plant target. Here we solve a 2.3 Å resolution crystal structure for Arabidopsis thaliana DHPS that is conjoined to 6-hydroxymethyl-7,8-dihydropterin pyrophosphokinase (HPPK), and we reveal a strong structural conservation with bacterial counterparts at the sulfonamide-binding pocket of DHPS. We demonstrate that asulam and the antibiotic sulfamethoxazole have herbicidal as well as antibacterial activity, and we explore the structural basis of their potency by modeling these compounds in mitochondrial HPPK/DHPS. Our findings suggest limited opportunity for the rational design of plant selectivity from asulam and indicate that pharmacokinetic or delivery differences between plants and microbes might be the best ways to safeguard this mode of action.
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Affiliation(s)
- Grishma Vadlamani
- School of Molecular Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia; The ARC Centre of Excellence in Plant Energy Biology, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia; Centre for Crop and Disease Management, School of Molecular and Life Sciences, Curtin University, Bentley, WA 6102, Australia
| | - Kirill V Sukhoverkov
- School of Molecular Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia; The ARC Centre of Excellence in Plant Energy Biology, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
| | - Joel Haywood
- School of Molecular Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia; The ARC Centre of Excellence in Plant Energy Biology, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia; Centre for Crop and Disease Management, School of Molecular and Life Sciences, Curtin University, Bentley, WA 6102, Australia
| | - Karen J Breese
- School of Molecular Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
| | - Mark F Fisher
- Centre for Crop and Disease Management, School of Molecular and Life Sciences, Curtin University, Bentley, WA 6102, Australia
| | - Keith A Stubbs
- School of Molecular Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
| | - Charles S Bond
- School of Molecular Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
| | - Joshua S Mylne
- School of Molecular Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia; The ARC Centre of Excellence in Plant Energy Biology, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia; Centre for Crop and Disease Management, School of Molecular and Life Sciences, Curtin University, Bentley, WA 6102, Australia.
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4
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Thiochromene candidates: design, synthesis, antimicrobial potential and in silico docking study. JOURNAL OF THE IRANIAN CHEMICAL SOCIETY 2022. [DOI: 10.1007/s13738-021-02391-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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5
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Müller R, Gerwel TM, Kimuda MP, Bishop ÖT, Veale CGL, Hoppe HC. Virtual screening and in vitro validation identifies the first reported inhibitors of Salmonella enterica HPPK. RSC Med Chem 2021; 12:1750-1756. [PMID: 34778775 PMCID: PMC8528203 DOI: 10.1039/d1md00237f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 08/23/2021] [Indexed: 11/21/2022] Open
Abstract
HPPK, which directly precedes DHPS in the folate biosynthetic pathway, is a promising but chronically under-exploited anti-microbial target. Here we report the identification of new S. enterica HPPK inhibitors, offering potential for new resistance circumventing S. enterica therapies as well as avenues for diversifying the current HPPK inhibitor space.
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Affiliation(s)
- Ronel Müller
- School of Chemistry and Physics, Pietermaritzburg Campus, University of KwaZulu-Natal Private Bag X01 Scottsville 3209 South Africa
| | - Tiaan M Gerwel
- Faculty of Pharmacy, Rhodes University Makhanda 6140 South Africa
| | - Magambo Phillip Kimuda
- Research Unit in Bioinformatics (RUBi), Department of Biochemistry and Microbiology, Rhodes University Makhanda 6140 South Africa
| | - Özlem Tastan Bishop
- Research Unit in Bioinformatics (RUBi), Department of Biochemistry and Microbiology, Rhodes University Makhanda 6140 South Africa
| | - Clinton G L Veale
- School of Chemistry and Physics, Pietermaritzburg Campus, University of KwaZulu-Natal Private Bag X01 Scottsville 3209 South Africa
| | - Heinrich C Hoppe
- Department of Biochemistry and Microbiology, Rhodes University Makhanda 6140 South Africa
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6
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Structure based design, synthesis, and biological evaluation of imidazole derivatives targeting dihydropteroate synthase enzyme. Bioorg Med Chem Lett 2021; 36:127819. [PMID: 33513385 DOI: 10.1016/j.bmcl.2021.127819] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 01/08/2021] [Accepted: 01/19/2021] [Indexed: 12/16/2022]
Abstract
In this study, we have designed and synthesized 2-((5-acetyl-1-(phenyl)-4-methyl-1H-imidazol-2-yl)thio)-N-(4-((benzyl)oxy)phenyl) acetamide derivatives. Antimicrobial activities of all the imidazole derivatives have been examined against Gram-positive and Gram-negative bacteria and results showed that the conjugates have appreciable antibacterial activity. Besides, several analogous were evaluated for their in vitro antiresistant bacterial strains such as Extended-spectrum beta-lactamases (ESBL), Vancomycin-resistant Enterococcus (VRE), and Methicillin-resistant Staphylococcus aureus (MRSA). The SAR revealed that the 12l compound resulted in potency against all bacterial strains as well as ESBL, VRE, and MRSA strains. Lipinski's rule of five, and ADME studies were preformed for all the synthesized compounds with Staphylococcus aureus dihydropteroate synthase (saDHPS) protein (PDB ID: 6CLV) and were found standard drug-likeness properties of conjugates. Moreover, the binding mode of the ligands with the protein study has been examined by molecular docking and results are quite promising. Besides, all the analogous were tested for their in vitro antituberculosis, antimalarial, and antioxidant activity.
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7
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Cheong MS, Seo KH, Chohra H, Yoon YE, Choe H, Kantharaj V, Lee YB. Influence of Sulfonamide Contamination Derived from Veterinary Antibiotics on Plant Growth and Development. Antibiotics (Basel) 2020; 9:antibiotics9080456. [PMID: 32731577 PMCID: PMC7460019 DOI: 10.3390/antibiotics9080456] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 07/25/2020] [Accepted: 07/27/2020] [Indexed: 11/16/2022] Open
Abstract
Veterinary antibiotics such as sulfonamides are widely used to increase feed efficiency and to protect against disease in livestock production. The sulfonamide antimicrobial mechanism involves the blocking of folate biosynthesis by inhibiting bacterial dihydropteroate synthase (DHPS) activity competitively. Interestingly, most treatment antibiotics can be released into the environment via manure and result in significant diffuse pollution in the environment. However, the physiological effects of sulfonamide during plant growth and development remain elusive because the plant response is dependent on folate biosynthesis and the concentration of antibiotics. Here, we present a chemical interaction docking model between Napa cabbage (Brassica campestris) DHPS and sulfamethoxazole and sulfamethazine, which are the most abundant sulfonamides detected in the environment. Furthermore, seedling growth inhibition was observed in lentil bean (Lens culinaris), rice (Oryza sativa), and Napa cabbage plants upon sulfonamide exposure. The results revealed that sulfonamide antibiotics target plant DHPS in a module similar to bacterial DHPS and affect early growth and the development of crop seedlings. Taking these results together, we suggest that sulfonamides act as pollutants in crop fields.
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Affiliation(s)
- Mi Sun Cheong
- Division of Applied Life Science (BK 21 Plus Program), Gyeongsang National University, Jinju 52828, Korea; (M.S.C.); (H.C.); (Y.E.Y.); (H.C.); (V.K.)
- Institute of Agriculture and Life Science (IALS), Gyeongsang National University, Jinju 52828, Korea
| | - Kyung Hye Seo
- Department of Herbal Crop Research, National Institute of Horticultural and Herbal Science, RDA, Eumsung 27709, Korea;
| | - Hadjer Chohra
- Division of Applied Life Science (BK 21 Plus Program), Gyeongsang National University, Jinju 52828, Korea; (M.S.C.); (H.C.); (Y.E.Y.); (H.C.); (V.K.)
| | - Young Eun Yoon
- Division of Applied Life Science (BK 21 Plus Program), Gyeongsang National University, Jinju 52828, Korea; (M.S.C.); (H.C.); (Y.E.Y.); (H.C.); (V.K.)
| | - Hyeonji Choe
- Division of Applied Life Science (BK 21 Plus Program), Gyeongsang National University, Jinju 52828, Korea; (M.S.C.); (H.C.); (Y.E.Y.); (H.C.); (V.K.)
| | - Vimalraj Kantharaj
- Division of Applied Life Science (BK 21 Plus Program), Gyeongsang National University, Jinju 52828, Korea; (M.S.C.); (H.C.); (Y.E.Y.); (H.C.); (V.K.)
| | - Yong Bok Lee
- Division of Applied Life Science (BK 21 Plus Program), Gyeongsang National University, Jinju 52828, Korea; (M.S.C.); (H.C.); (Y.E.Y.); (H.C.); (V.K.)
- Institute of Agriculture and Life Science (IALS), Gyeongsang National University, Jinju 52828, Korea
- Correspondence: ; Tel.: +82-557-721-967
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8
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Kordus SL, Baughn AD. Revitalizing antifolates through understanding mechanisms that govern susceptibility and resistance. MEDCHEMCOMM 2019; 10:880-895. [PMID: 31303985 PMCID: PMC6595967 DOI: 10.1039/c9md00078j] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 05/07/2019] [Indexed: 12/12/2022]
Abstract
In prokaryotes and eukaryotes, folate (vitamin B9) is an essential metabolic cofactor required for all actively growing cells. Specifically, folate serves as a one-carbon carrier in the synthesis of amino acids (such as methionine, serine, and glycine), N-formylmethionyl-tRNA, coenzyme A, purines and thymidine. Many microbes are unable to acquire folates from their environment and rely on de novo folate biosynthesis. In contrast, mammals lack the de novo folate biosynthesis pathway and must obtain folate from commensal microbiota or the environment using proton-coupled folate transporters. The essentiality and dichotomy between mammalian and bacterial folate biosynthesis and utilization pathways make it an ideal drug target for the development of antimicrobial agents and cancer chemotherapeutics. In this minireview, we discuss general aspects of folate biosynthesis and the underlying mechanisms that govern susceptibility and resistance of organisms to antifolate drugs.
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Affiliation(s)
- Shannon Lynn Kordus
- Department of Microbiology and Immunology , University of Minnesota , Minneapolis , MN , USA .
| | - Anthony David Baughn
- Department of Microbiology and Immunology , University of Minnesota , Minneapolis , MN , USA .
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9
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Yogavel M, Nettleship JE, Sharma A, Harlos K, Jamwal A, Chaturvedi R, Sharma M, Jain V, Chhibber-Goel J, Sharma A. Structure of 6-hydroxymethyl-7,8-dihydropterin pyrophosphokinase-dihydropteroate synthase from Plasmodium vivax sheds light on drug resistance. J Biol Chem 2018; 293:14962-14972. [PMID: 30104413 DOI: 10.1074/jbc.ra118.004558] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 08/08/2018] [Indexed: 11/06/2022] Open
Abstract
The genomes of the malaria-causing Plasmodium parasites encode a protein fused of 6-hydroxymethyl-7,8-dihydropterin pyrophosphokinase (HPPK) and dihydropteroate synthase (DHPS) domains that catalyze sequential reactions in the folate biosynthetic pathway. Whereas higher organisms derive folate from their diet and lack the enzymes for its synthesis, most eubacteria and a number of lower eukaryotes including malaria parasites synthesize tetrahydrofolate via DHPS. Plasmodium falciparum (Pf) and Plasmodium vivax (Pv) HPPK-DHPSs are currently targets of drugs like sulfadoxine (SDX). The SDX effectiveness as an antimalarial drug is increasingly diminished by the rise and spread of drug-resistant mutations. Here, we present the crystal structure of PvHPPK-DHPS in complex with four substrates/analogs, revealing the bifunctional PvHPPK-DHPS architecture in an unprecedented state of enzymatic activation. SDX's effect on HPPK-DHPS is due to 4-amino benzoic acid (pABA) mimicry, and the PvHPPK-DHPS structure sheds light on the SDX-binding cavity, as well as on mutations that effect SDX potency. We mapped five dominant drug resistance mutations in PvHPPK-DHPS: S382A, A383G, K512E/D, A553G, and V585A, most of which occur individually or in clusters proximal to the pABA-binding site. We found that these resistance mutations subtly alter the intricate enzyme/pABA/SDX interactions such that DHPS affinity for pABA is diminished only moderately, but its affinity for SDX is changed substantially. In conclusion, the PvHPPK-DHPS structure rationalizes and unravels the structural bases for SDX resistance mutations and highlights architectural features in HPPK-DHPSs from malaria parasites that can form the basis for developing next-generation anti-folate agents to combat malaria parasites.
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Affiliation(s)
- Manickam Yogavel
- From the Molecular Medicine-Structural Parasitology Group, International Centre for Genetic Engineering and Biotechnology, New Delhi 110067, India,
| | - Joanne E Nettleship
- the Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, United Kingdom, and.,the Oxford Protein Production Facility, United Kingdom Research Complex at Harwell, Rutherford Appleton Laboratory, Oxford OX11 0FA, United Kingdom
| | - Akansha Sharma
- From the Molecular Medicine-Structural Parasitology Group, International Centre for Genetic Engineering and Biotechnology, New Delhi 110067, India
| | - Karl Harlos
- the Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, United Kingdom, and
| | - Abhishek Jamwal
- From the Molecular Medicine-Structural Parasitology Group, International Centre for Genetic Engineering and Biotechnology, New Delhi 110067, India
| | - Rini Chaturvedi
- From the Molecular Medicine-Structural Parasitology Group, International Centre for Genetic Engineering and Biotechnology, New Delhi 110067, India
| | - Manmohan Sharma
- From the Molecular Medicine-Structural Parasitology Group, International Centre for Genetic Engineering and Biotechnology, New Delhi 110067, India
| | - Vitul Jain
- the Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, United Kingdom, and
| | - Jyoti Chhibber-Goel
- From the Molecular Medicine-Structural Parasitology Group, International Centre for Genetic Engineering and Biotechnology, New Delhi 110067, India
| | - Amit Sharma
- From the Molecular Medicine-Structural Parasitology Group, International Centre for Genetic Engineering and Biotechnology, New Delhi 110067, India
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10
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Dennis ML, Lee MD, Harjani JR, Ahmed M, DeBono AJ, Pitcher NP, Wang ZC, Chhabra S, Barlow N, Rahmani R, Cleary B, Dolezal O, Hattarki M, Aurelio L, Shonberg J, Graham B, Peat TS, Baell JB, Swarbrick JD. 8-Mercaptoguanine Derivatives as Inhibitors of Dihydropteroate Synthase. Chemistry 2018; 24:1922-1930. [PMID: 29171692 DOI: 10.1002/chem.201704730] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Indexed: 01/26/2023]
Abstract
Dihydropteroate synthase (DHPS) is an enzyme of the folate biosynthesis pathway, which catalyzes the formation of 7,8-dihydropteroate (DHPt) from 6-hydroxymethyl-7,8-dihydropterin pyrophosphate (DHPPP) and para-aminobenzoic acid (pABA). DHPS is the long-standing target of the sulfonamide class of antibiotics that compete with pABA. In the wake of sulfa drug resistance, targeting the structurally rigid (and more conserved) pterin site has been proposed as an alternate strategy to inhibit DHPS in wild-type and sulfa drug resistant strains. Following the work on developing pterin-site inhibitors of the adjacent enzyme 6-hydroxymethyl-7,8-dihydropterin pyrophosphokinase (HPPK), we now present derivatives of 8-mercaptoguanine, a fragment that binds weakly within both enzymes, and quantify sub-μm binding using surface plasmon resonance (SPR) to Escherichia coli DHPS (EcDHPS). Eleven ligand-bound EcDHPS crystal structures delineate the structure-activity relationship observed providing a structural framework for the rational development of novel, substrate-envelope-compliant DHPS inhibitors.
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Affiliation(s)
- Matthew L Dennis
- Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, 3052, Victoria, Australia.,CSIRO Biomedical Program, Manufacturing, Parkville, 3052, Victoria, Australia
| | - Michael D Lee
- Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, 3052, Victoria, Australia.,CSIRO Biomedical Program, Manufacturing, Parkville, 3052, Victoria, Australia
| | - Jitendra R Harjani
- Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, 3052, Victoria, Australia
| | - Mohamed Ahmed
- Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, 3052, Victoria, Australia.,School of Pharmacy, University College London, Bloomsbury, London, WC1N 1AX, UK
| | - Aaron J DeBono
- Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, 3052, Victoria, Australia
| | - Noel P Pitcher
- Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, 3052, Victoria, Australia
| | - Zhong-Chang Wang
- Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, 3052, Victoria, Australia.,State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing, 210093, P. R. China
| | - Sandeep Chhabra
- Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, 3052, Victoria, Australia
| | - Nicholas Barlow
- Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, 3052, Victoria, Australia
| | - Raphaël Rahmani
- Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, 3052, Victoria, Australia
| | - Ben Cleary
- Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, 3052, Victoria, Australia
| | - Olan Dolezal
- CSIRO Biomedical Program, Manufacturing, Parkville, 3052, Victoria, Australia
| | - Meghan Hattarki
- CSIRO Biomedical Program, Manufacturing, Parkville, 3052, Victoria, Australia
| | - Luigi Aurelio
- Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, 3052, Victoria, Australia
| | - Jeremy Shonberg
- Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, 3052, Victoria, Australia
| | - Bim Graham
- Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, 3052, Victoria, Australia
| | - Thomas S Peat
- CSIRO Biomedical Program, Manufacturing, Parkville, 3052, Victoria, Australia
| | - Jonathan B Baell
- Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, 3052, Victoria, Australia.,School of Pharmaceutical Sciences, Nanjing Tech University, Nanjing, 211816, P. R. China
| | - James D Swarbrick
- Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, 3052, Victoria, Australia
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11
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Oguike MC, Falade CO, Shu E, Enato IG, Watila I, Baba ES, Bruce J, Webster J, Hamade P, Meek S, Chandramohan D, Sutherland CJ, Warhurst D, Roper C. Molecular determinants of sulfadoxine-pyrimethamine resistance in Plasmodium falciparum in Nigeria and the regional emergence of dhps 431V. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2016; 6:220-229. [PMID: 27821281 PMCID: PMC5094156 DOI: 10.1016/j.ijpddr.2016.08.004] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/12/2016] [Accepted: 08/12/2016] [Indexed: 11/19/2022]
Abstract
There are few published reports of mutations in dihydropteroate synthetase (dhps) and dihydrofolate reductase (dhfr) genes in P. falciparum populations in Nigeria, but one previous study has recorded a novel dhps mutation at codon 431 among infections imported to the United Kingdom from Nigeria. To assess how widespread this mutation is among parasites in different parts of the country and consequently fill the gap in sulfadoxine-pyrimethamine (SP) resistance data in Nigeria, we retrospectively analysed 1000 filter paper blood spots collected in surveys of pregnant women and children with uncomplicated falciparum malaria between 2003 and 2015 from four sites in the south and north. Genomic DNA was extracted from filter paper blood spots and placental impressions. Point mutations at codons 16, 50, 51, 59, 108, 140 and 164 of the dhfr gene and codons 431, 436, 437, 540, 581 and 613 of the dhps gene were evaluated by nested PCR amplification followed by direct sequencing. The distribution of the dhps-431V mutation was widespread throughout Nigeria with the highest prevalence in Enugu (46%). In Ibadan where we had sequential sampling, its prevalence increased from 0% to 6.5% between 2003 and 2008. Although there were various combinations of dhps mutations with 431V, the combination 431V + 436A + 437G+581G+613S was the most common. All these observations support the view that dhps-431V is on the increase. In addition, P. falciparum DHPS crystal structure modelling shows that the change from Isoleucine to Valine (dhps-431V) could alter the effects of both S436A/F and A437G, which closely follow the 2nd β-strand. Consequently, it is now a research priority to assess the implications of dhps-VAGKGS mutant haplotype on continuing use of SP in seasonal malaria chemoprevention (SMC) and intermittent preventive treatment in pregnancy (IPTp). Our data also provides surveillance data for SP resistance markers in Nigeria between 2003 and 2015. We present data on dhps and dhfr mutations in P. falciparum populations in Nigeria. Increased prevalence of I431V mutation was seen between 2003 and 2015 from 0 to 36%. The 431V + 436A + 437G + 581G + 613S was the most common with dhps-431V mutation. Crystal structure modelling of Pf DHPS shows that 431Vcould alter S436A and A437G.
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Affiliation(s)
- Mary C Oguike
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom.
| | - Catherine O Falade
- Department of Pharmacology and Therapeutics, College of Medicine, University of Ibadan, Ibadan, Nigeria
| | - Elvis Shu
- Department of Pharmacology and Therapeutics, College of Medicine, University of Nigeria, Enugu Campus, Enugu, Nigeria
| | - Izehiuwa G Enato
- Department of Child Health, University of Benin Teaching Hospital, Benin City, Nigeria
| | - Ismaila Watila
- Department of Paediatrics, Specialist Hospital Maiduguri, Borno State, Nigeria
| | - Ebenezer S Baba
- Malaria Consortium, Regional Office for Africa, Kampala, Uganda
| | - Jane Bruce
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Jayne Webster
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | | | | | - Daniel Chandramohan
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Colin J Sutherland
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - David Warhurst
- Department of Pathogen Molecular Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Cally Roper
- Department of Pathogen Molecular Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
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12
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Stratton CF, Namanja-Magliano HA, Cameron SA, Schramm VL. Binding Isotope Effects for para-Aminobenzoic Acid with Dihydropteroate Synthase from Staphylococcus aureus and Plasmodium falciparum. ACS Chem Biol 2015; 10:2182-6. [PMID: 26288086 PMCID: PMC4648244 DOI: 10.1021/acschembio.5b00490] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Dihydropteroate synthase is a key enzyme in folate biosynthesis and is the target of the sulfonamide class of antimicrobials. Equilibrium binding isotope effects and density functional theory calculations indicate that the substrate binding sites for para-aminobenzoic acid on the dihydropteroate synthase enzymes from Staphylococcus aureus and Plasmodium falciparum present distinct chemical environments. Specifically, we show that para-aminobenzoic acid occupies a more sterically constrained vibrational environment when bound to dihydropteroate synthase from P. falciparum relative to that of S. aureus. Deletion of a nonhomologous, parasite-specific insert from the plasmodial dihydropteroate synthase abrogated the binding of para-aminobenzoic acid. The loop specific to P. falciparum is important for effective substrate binding and therefore plays a role in modulating the chemical environment at the substrate binding site.
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Affiliation(s)
| | | | - Scott A. Cameron
- Department of Biochemistry, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York 10461, United States
| | - Vern L. Schramm
- Department of Biochemistry, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York 10461, United States
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13
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Shaw GX, Li Y, Shi G, Wu Y, Cherry S, Needle D, Zhang D, Tropea JE, Waugh DS, Yan H, Ji X. Structural enzymology and inhibition of the bi-functional folate pathway enzyme HPPK-DHPS from the biowarfare agent Francisella tularensis. FEBS J 2014; 281:4123-37. [PMID: 24975935 PMCID: PMC5600157 DOI: 10.1111/febs.12896] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2014] [Revised: 06/20/2014] [Accepted: 06/25/2014] [Indexed: 11/29/2022]
Abstract
UNLABELLED Two valid targets for antibiotic development, 6-hydroxymethyl-7,8-dihydropterin pyrophosphokinase (HPPK) and dihydropteroate synthase (DHPS), catalyze consecutive reactions in folate biosynthesis. In Francisella tularensis (Ft), these two activities are contained in a single protein, FtHPPK-DHPS. Although Pemble et al. (PLoS One 5, e14165) determined the structure of FtHPPK-DHPS, they were unable to measure the kinetic parameters of the enzyme. In this study, we elucidated the binding and inhibitory activities of two HPPK inhibitors (HP-18 and HP-26) against FtHPPK-DHPS, determined the structure of FtHPPK-DHPS in complex with HP-26, and measured the kinetic parameters for the dual enzymatic activities of FtHPPK-DHPS. The biochemical analyses showed that HP-18 and HP-26 have significant isozyme selectivity, and that FtHPPK-DHPS is unique in that the catalytic efficiency of its DHPS activity is only 1/260,000 of that of Escherichia coli DHPS. Sequence and structural analyses suggest that HP-26 is an excellent lead for developing therapeutic agents for tularemia, and that the very low DHPS activity is due, at least in part, to the lack of a key residue that interacts with the substrate p-aminobenzoic acid (pABA). A BLAST search of the genomes of ten F. tularensis strains indicated that the bacterium contains a single FtHPPK-DHPS. The marginal DHPS activity and the single copy existence of FtHPPK-DHPS in F. tularensis make this bacterium more vulnerable to DHPS inhibitors. Current sulfa drugs are ineffective against tularemia; new inhibitors targeting the unique pABA-binding pocket may be effective and less subject to resistance because any mutations introducing resistance may make the marginal DHPS activity unable to support the growth of F. tularensis. DATABASE The coordinates and structure factors have been deposited in the Protein Data Bank under accession code 4PZV.
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Affiliation(s)
- Gary X. Shaw
- Macromolecular Crystallography Laboratory, National Cancer Institute, Frederick, MD, USA
| | - Yue Li
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, USA
| | - Genbin Shi
- Macromolecular Crystallography Laboratory, National Cancer Institute, Frederick, MD, USA
| | - Yan Wu
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, USA
| | - Scott Cherry
- Macromolecular Crystallography Laboratory, National Cancer Institute, Frederick, MD, USA
| | - Danielle Needle
- Macromolecular Crystallography Laboratory, National Cancer Institute, Frederick, MD, USA
| | - Di Zhang
- Macromolecular Crystallography Laboratory, National Cancer Institute, Frederick, MD, USA
| | - Joseph E. Tropea
- Macromolecular Crystallography Laboratory, National Cancer Institute, Frederick, MD, USA
| | - David S. Waugh
- Macromolecular Crystallography Laboratory, National Cancer Institute, Frederick, MD, USA
| | - Honggao Yan
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, USA
| | - Xinhua Ji
- Macromolecular Crystallography Laboratory, National Cancer Institute, Frederick, MD, USA
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14
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Yao J, Abdelrahman YM, Robertson RM, Cox JV, Belland RJ, White SW, Rock CO. Type II fatty acid synthesis is essential for the replication of Chlamydia trachomatis. J Biol Chem 2014; 289:22365-76. [PMID: 24958721 DOI: 10.1074/jbc.m114.584185] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The major phospholipid classes of the obligate intracellular bacterial parasite Chlamydia trachomatis are the same as its eukaryotic host except that they also contain chlamydia-made branched-chain fatty acids in the 2-position. Genomic analysis predicts that C. trachomatis is capable of type II fatty acid synthesis (FASII). AFN-1252 was deployed as a chemical tool to specifically inhibit the enoyl-acyl carrier protein reductase (FabI) of C. trachomatis to determine whether chlamydial FASII is essential for replication within the host. The C. trachomatis FabI (CtFabI) is a homotetramer and exhibited typical FabI kinetics, and its expression complemented an Escherichia coli fabI(Ts) strain. AFN-1252 inhibited CtFabI by binding to the FabI·NADH complex with an IC50 of 0.9 μM at saturating substrate concentration. The x-ray crystal structure of the CtFabI·NADH·AFN-1252 ternary complex revealed the specific interactions between the drug, protein, and cofactor within the substrate binding site. AFN-1252 treatment of C. trachomatis-infected HeLa cells at any point in the infectious cycle caused a decrease in infectious titers that correlated with a decrease in branched-chain fatty acid biosynthesis. AFN-1252 treatment at the time of infection prevented the first cell division of C. trachomatis, although the cell morphology suggested differentiation into a metabolically active reticulate body. These results demonstrate that FASII activity is essential for C. trachomatis proliferation within its eukaryotic host and validate CtFabI as a therapeutic target against C. trachomatis.
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Affiliation(s)
| | - Yasser M Abdelrahman
- the Department of Microbiology, Immunology, and Biochemistry, University of Tennessee Health Science Center, Memphis, Tennessee 38163, and the Department of Microbiology and Immunology, Faculty of Pharmacy, Cairo University, Cairo 11562, Egypt
| | - Rosanna M Robertson
- Structural Biology, St. Jude Children's Research Hospital, Memphis, Tennessee 48105
| | - John V Cox
- the Department of Microbiology, Immunology, and Biochemistry, University of Tennessee Health Science Center, Memphis, Tennessee 38163, and
| | - Robert J Belland
- the Department of Microbiology, Immunology, and Biochemistry, University of Tennessee Health Science Center, Memphis, Tennessee 38163, and
| | - Stephen W White
- Structural Biology, St. Jude Children's Research Hospital, Memphis, Tennessee 48105
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15
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Yun MK, Hoagland D, Kumar G, Waddell MB, Rock CO, Lee RE, White SW. The identification, analysis and structure-based development of novel inhibitors of 6-hydroxymethyl-7,8-dihydropterin pyrophosphokinase. Bioorg Med Chem 2014; 22:2157-65. [PMID: 24613625 DOI: 10.1016/j.bmc.2014.02.022] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2013] [Revised: 02/04/2014] [Accepted: 02/14/2014] [Indexed: 01/19/2023]
Abstract
6-Hydroxymethyl-7,8-dihydropterin pyrophosphokinase (HPPK) is an essential enzyme in the microbial folate biosynthetic pathway. This pathway has proven to be an excellent target for antimicrobial development, but widespread resistance to common therapeutics including the sulfa drugs has stimulated interest in HPPK as an alternative target in the pathway. A screen of a pterin-biased compound set identified several HPPK inhibitors that contain an aryl substituted 8-thioguanine scaffold, and structural analyses showed that these compounds engage the HPPK pterin-binding pocket and an induced cryptic pocket. A preliminary structure activity relationship profile was developed from biophysical and biochemical characterizations of derivative molecules. Also, a similarity search identified additional scaffolds that bind more tightly within the HPPK pterin pocket. These inhibitory scaffolds have the potential for rapid elaboration into novel lead antimicrobial agents.
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Affiliation(s)
- Mi-Kyung Yun
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Daniel Hoagland
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Gyanendra Kumar
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - M Brett Waddell
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Charles O Rock
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, TN 38105, USA; Department of Microbiology, Immunology and Biochemistry, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Richard E Lee
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, TN 38105, USA; Department of Microbiology, Immunology and Biochemistry, University of Tennessee Health Science Center, Memphis, TN 38163, USA.
| | - Stephen W White
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA; Department of Microbiology, Immunology and Biochemistry, University of Tennessee Health Science Center, Memphis, TN 38163, USA.
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16
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Abstract
More research effort needs to be invested in antimicrobial drug development to address the increasing threat of multidrug-resistant organisms. The enzyme DHPS has been a validated drug target for over 70 years as the target for the highly successful sulfa drugs. The use of sulfa drugs has been compromised by the widespread presence of resistant organisms and the adverse side effects associated with their use. Despite the large amount of structural information available for DHPS, few recent publications address the possibility of using this knowledge for novel drug design. This article reviews the relevant papers and patents that report promising new small-molecule inhibitors of DHPS, and discuss these data in light of new insights into the DHPS catalytic mechanism and recently determined crystal structures of DHPS bound to potent small-molecule inhibitors. This new functional understanding confirms that DHPS deserves further consideration as an antimicrobial drug target.
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17
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In-silico analysis of 6-hydroxymethyl-7,8-dihydropterin pyrophosphokinase (HPPK): a potential drug target against Salmonella enterica serovar typhi. Med Chem Res 2014. [DOI: 10.1007/s00044-013-0641-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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18
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Utility of the Biosynthetic Folate Pathway for Targets in Antimicrobial Discovery. Antibiotics (Basel) 2014; 3:1-28. [PMID: 27025730 PMCID: PMC4790348 DOI: 10.3390/antibiotics3010001] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Revised: 01/08/2014] [Accepted: 01/09/2014] [Indexed: 01/07/2023] Open
Abstract
The need for new antimicrobials is great in face of a growing pool of resistant pathogenic organisms. This review will address the potential for antimicrobial therapy based on polypharmacological activities within the currently utilized bacterial biosynthetic folate pathway. The folate metabolic pathway leads to synthesis of required precursors for cellular function and contains a critical node, dihydrofolate reductase (DHFR), which is shared between prokaryotes and eukaryotes. The DHFR enzyme is currently targeted by methotrexate in anti-cancer therapies, by trimethoprim for antibacterial uses, and by pyrimethamine for anti-protozoal applications. An additional anti-folate target is dihyropteroate synthase (DHPS), which is unique to prokaryotes as they cannot acquire folate through dietary means. It has been demonstrated as a primary target for the longest standing antibiotic class, the sulfonamides, which act synergistically with DHFR inhibitors. Investigations have revealed most DHPS enzymes possess the ability to utilize sulfa drugs metabolically, producing alternate products that presumably inhibit downstream enzymes requiring the produced dihydropteroate. Recent work has established an off-target effect of sulfonamide antibiotics on a eukaryotic enzyme, sepiapterin reductase, causing alterations in neurotransmitter synthesis. Given that inhibitors of both DHFR and DHPS are designed to mimic their cognate substrate, which contain shared substructures, it is reasonable to expect such “off-target” effects. These inhibitors are also likely to interact with the enzymatic neighbors in the folate pathway that bind products of the DHFR or DHPS enzymes and/or substrates of similar substructure. Computational studies designed to assess polypharmacology reiterate these conclusions. This leads to hypotheses exploring the vast utility of multiple members of the folate pathway for modulating cellular metabolism, and includes an appealing capacity for prokaryotic-specific polypharmacology for antimicrobial applications.
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19
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Chhabra S, Barlow N, Dolezal O, Hattarki MK, Newman J, Peat TS, Graham B, Swarbrick JD. Exploring the chemical space around 8-mercaptoguanine as a route to new inhibitors of the folate biosynthesis enzyme HPPK. PLoS One 2013; 8:e59535. [PMID: 23565155 PMCID: PMC3614987 DOI: 10.1371/journal.pone.0059535] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2012] [Accepted: 02/15/2013] [Indexed: 11/18/2022] Open
Abstract
As the second essential enzyme of the folate biosynthetic pathway, the potential antimicrobial target, HPPK (6-hydroxymethyl-7,8-dihydropterin pyrophosphokinase), catalyzes the Mg(2+-)dependant transfer of pyrophosphate from the cofactor (ATP) to the substrate, 6-hydroxymethyl-7,8-dihydropterin. Recently, we showed that 8-mercaptoguanine (8-MG) bound at the substrate site (KD ∼13 µM), inhibited the S. aureus enzyme (SaHPPK) (IC50 ∼ 41 µM), and determined the structure of the SaHPPK/8-MG complex. Here we present the synthesis of a series of guanine derivatives, together with their HPPK binding affinities, as determined by SPR and ITC analysis. The binding mode of the most potent was investigated using 2D NMR spectroscopy and X-ray crystallography. The results indicate, firstly, that the SH group of 8-MG makes a significant contribution to the free energy of binding. Secondly, direct N(9) substitution, or tautomerization arising from N(7) substitution in some cases, leads to a dramatic reduction in affinity due to loss of a critical N(9)-H···Val46 hydrogen bond, combined with the limited space available around the N(9) position. The water-filled pocket under the N(7) position is significantly more tolerant of substitution, with a hydroxyl ethyl 8-MG derivative attached to N(7) (compound 21a) exhibiting an affinity for the apo enzyme comparable to the parent compound (KD ∼ 12 µM). In contrast to 8-MG, however, 21a displays competitive binding with the ATP cofactor, as judged by NMR and SPR analysis. The 1.85 Å X-ray structure of the SaHPPK/21a complex confirms that extension from the N(7) position towards the Mg(2+)-binding site, which affords the only tractable route out from the pterin-binding pocket. Promising strategies for the creation of more potent binders might therefore include the introduction of groups capable of interacting with the Mg(2+) centres or Mg(2+)-binding residues, as well as the development of bitopic inhibitors featuring 8-MG linked to a moiety targeting the ATP cofactor binding site.
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Affiliation(s)
- Sandeep Chhabra
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Australia
- CSIRO Division of Materials, Science and Engineering, Parkville, Australia
| | - Nicholas Barlow
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Australia
| | - Olan Dolezal
- CSIRO Division of Materials, Science and Engineering, Parkville, Australia
| | - Meghan K. Hattarki
- CSIRO Division of Materials, Science and Engineering, Parkville, Australia
| | - Janet Newman
- CSIRO Division of Materials, Science and Engineering, Parkville, Australia
| | - Thomas S. Peat
- CSIRO Division of Materials, Science and Engineering, Parkville, Australia
| | - Bim Graham
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Australia
| | - James D. Swarbrick
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Australia
- * E-mail:
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20
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Chu WT, Zhang JL, Zheng QC, Chen L, Xue Q, Zhang HX. Insights into the drug resistance induced by the BaDHPS mutations: molecular dynamic simulations and MM/GBSA studies. J Biomol Struct Dyn 2012; 31:1127-36. [PMID: 23030549 DOI: 10.1080/07391102.2012.726529] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Dihydropteroate synthase (DHPS) is essential for the folic acid biosynthetic pathway in prokaryotes; the mutation forms for DHPS are found to be relative to the urgent drug resistance problems. In our study, the Bacillus anthracis DHPS (BaDHPS) was selected for molecular dynamics and binding free energy studies to investigate the biochemistry behaviors of the wild-type and mutation form BaDHPS proteins (D184N and K220Q). It is found that the conformational change of the ligand dihydropteroate sulfathiazole binding site in mutation D184N and K220Q systems is mainly attributed from the Loop 1, Loop 2, and Loop 7 regions, and the binding free energy of these mutation systems is lower than that of the wild-type system. Additionally, some important hydrogen bonds of the mutation systems are disrupted during the simulations. But the shortening of the distance between residue Thr67 and the ligand would cause significant change of the binding pose in the K220Q system. These studies of DHPS family will be helpful for further drug resistance investigations. An animated Interactive 3D Complement (I3DC) is available in Proteopedia at http://proteopedia.org/w/Journal:JBSD:24.
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Affiliation(s)
- Wen-Ting Chu
- a State Key Laboratory of Theoretical and Computational Chemistry , Institute of Theoretical Chemistry, Jilin University , Changchun , 130023 , China
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21
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Yun MK, Wu Y, Li Z, Zhao Y, Waddell MB, Ferreira AM, Lee RE, Bashford D, White SW. Catalysis and sulfa drug resistance in dihydropteroate synthase. Science 2012; 335:1110-4. [PMID: 22383850 PMCID: PMC3531234 DOI: 10.1126/science.1214641] [Citation(s) in RCA: 139] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The sulfonamide antibiotics inhibit dihydropteroate synthase (DHPS), a key enzyme in the folate pathway of bacteria and primitive eukaryotes. However, resistance mutations have severely compromised the usefulness of these drugs. We report structural, computational, and mutagenesis studies on the catalytic and resistance mechanisms of DHPS. By performing the enzyme-catalyzed reaction in crystalline DHPS, we have structurally characterized key intermediates along the reaction pathway. Results support an S(N)1 reaction mechanism via formation of a novel cationic pterin intermediate. We also show that two conserved loops generate a substructure during catalysis that creates a specific binding pocket for p-aminobenzoic acid, one of the two DHPS substrates. This substructure, together with the pterin-binding pocket, explains the roles of the conserved active-site residues and reveals how sulfonamide resistance arises.
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Affiliation(s)
- Mi-Kyung Yun
- Department of Structural Biology, St. Jude Children’s Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - Yinan Wu
- Department of Structural Biology, St. Jude Children’s Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - Zhenmei Li
- Department of Structural Biology, St. Jude Children’s Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - Ying Zhao
- Department of Chemical Biology and Therapeutics, St. Jude Children’s Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - M. Brett Waddell
- The Hartwell Center for Bioinformatics and Biotechnology, St. Jude Children’s Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - Antonio M. Ferreira
- Department of Structural Biology, St. Jude Children’s Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
- Information Sciences, St. Jude Children’s Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - Richard E. Lee
- Department of Chemical Biology and Therapeutics, St. Jude Children’s Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - Donald Bashford
- Department of Structural Biology, St. Jude Children’s Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - Stephen W. White
- Department of Structural Biology, St. Jude Children’s Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
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22
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Chhabra S, Dolezal O, Collins BM, Newman J, Simpson JS, Macreadie IG, Fernley R, Peat TS, Swarbrick JD. Structure of S. aureus HPPK and the discovery of a new substrate site inhibitor. PLoS One 2012; 7:e29444. [PMID: 22276115 PMCID: PMC3261883 DOI: 10.1371/journal.pone.0029444] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2011] [Accepted: 11/28/2011] [Indexed: 12/17/2022] Open
Abstract
The first structural and biophysical data on the folate biosynthesis pathway enzyme and drug target, 6-hydroxymethyl-7,8-dihydropterin pyrophosphokinase (SaHPPK), from the pathogen Staphylococcus aureus is presented. HPPK is the second essential enzyme in the pathway catalysing the pyrophosphoryl transfer from cofactor (ATP) to the substrate (6-hydroxymethyl-7,8-dihydropterin, HMDP). In-silico screening identified 8-mercaptoguanine which was shown to bind with an equilibrium dissociation constant, Kd, of ∼13 µM as measured by isothermal titration calorimetry (ITC) and surface plasmon resonance (SPR). An IC50 of ∼41 µM was determined by means of a luminescent kinase assay. In contrast to the biological substrate, the inhibitor has no requirement for magnesium or the ATP cofactor for competitive binding to the substrate site. The 1.65 Å resolution crystal structure of the inhibited complex showed that it binds in the pterin site and shares many of the key intermolecular interactions of the substrate. Chemical shift and 15N heteronuclear NMR measurements reveal that the fast motion of the pterin-binding loop (L2) is partially dampened in the SaHPPK/HMDP/α,β-methylene adenosine 5′-triphosphate (AMPCPP) ternary complex, but the ATP loop (L3) remains mobile on the µs-ms timescale. In contrast, for the SaHPPK/8-mercaptoguanine/AMPCPP ternary complex, the loop L2 becomes rigid on the fast timescale and the L3 loop also becomes more ordered – an observation that correlates with the large entropic penalty associated with inhibitor binding as revealed by ITC. NMR data, including 15N-1H residual dipolar coupling measurements, indicate that the sulfur atom in the inhibitor is important for stabilizing and restricting important motions of the L2 and L3 catalytic loops in the inhibited ternary complex. This work describes a comprehensive analysis of a new HPPK inhibitor, and may provide a foundation for the development of novel antimicrobials targeting the folate biosynthetic pathway.
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Affiliation(s)
- Sandeep Chhabra
- Medicinal Chemistry and Drug Action, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Australia
- CSIRO Division of Materials, Science and Engineering, Parkville, Australia
| | - Olan Dolezal
- CSIRO Division of Materials, Science and Engineering, Parkville, Australia
| | - Brett M. Collins
- Institute for Molecular Bioscience, The University of Queensland, Australia
| | - Janet Newman
- CSIRO Division of Materials, Science and Engineering, Parkville, Australia
| | - Jamie S. Simpson
- Medicinal Chemistry and Drug Action, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Australia
| | - Ian G. Macreadie
- School of Applied Sciences, RMIT University, Bundoora, Australia
| | - Ross Fernley
- CSIRO Division of Materials, Science and Engineering, Parkville, Australia
| | - Thomas S. Peat
- CSIRO Division of Materials, Science and Engineering, Parkville, Australia
| | - James D. Swarbrick
- Medicinal Chemistry and Drug Action, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Australia
- * E-mail:
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Morgan RE, Batot GO, Dement JM, Rao VA, Eadsforth TC, Hunter WN. Crystal structures of Burkholderia cenocepacia dihydropteroate synthase in the apo-form and complexed with the product 7,8-dihydropteroate. BMC STRUCTURAL BIOLOGY 2011; 11:21. [PMID: 21554707 PMCID: PMC3098144 DOI: 10.1186/1472-6807-11-21] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/04/2011] [Accepted: 05/09/2011] [Indexed: 11/22/2022]
Abstract
Background The enzyme dihydropteroate synthase (DHPS) participates in the de novo synthesis of folate cofactors by catalyzing the formation of 7,8-dihydropteroate from condensation of p-aminobenzoic acid with 6-hydroxymethyl-7,8-dihydropteroate pyrophosphate. DHPS is absent from humans, who acquire folates from diet, and has been validated as an antimicrobial therapeutic target by chemical and genetic means. The bacterium Burkholderia cenocepacia is an opportunistic pathogen and an infective agent of cystic fibrosis patients. The organism is highly resistant to antibiotics and there is a recognized need for the identification of new drugs against Burkholderia and related Gram-negative pathogens. Our characterization of the DHPS active site and interactions with the enzyme product are designed to underpin early stage drug discovery. Results An efficient recombinant protein expression system for DHPS from B. cenocepacia (BcDHPS) was prepared, the dimeric enzyme purified in high yield and crystallized. The structure of the apo-enzyme and the complex with the product 7,8-dihydropteroate have been determined to 2.35 Å and 1.95 Å resolution respectively in distinct orthorhombic crystal forms. The latter represents the first crystal structure of the DHPS-pterin product complex, reveals key interactions involved in ligand binding, and reinforces data generated by other structural studies. Comparisons with orthologues identify plasticity near the substrate-binding pocket and in particular a range of loop conformations that contribute to the architecture of the DHPS active site. These structural data provide a foundation for hit discovery. An intriguing observation, an artifact of the analysis, that of a potential sulfenamide bond within the ligand complex structure is mentioned. Conclusion Structural similarities between BcDHPS and orthologues from other Gram-negative species are evident as expected on the basis of a high level of sequence identity. The presence of 7,8-dihydropteroate in the binding site provides details about ligand recognition by the enzyme and the different states of the enzyme allow us to visualize distinct conformational states of loops adjacent to the active site. Improved drugs to combat infections by Burkholderia sp. and related Gram-negative bacteria are sought and our study now provides templates to assist that process and allow us to discuss new ways of inhibiting DHPS.
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Affiliation(s)
- Rachel E Morgan
- Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dow Street, Dundee, DD1 5EH, UK
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