51
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Moyersoen J, Choe J, Fan E, Hol WGJ, Michels PAM. Biogenesis of peroxisomes and glycosomes: trypanosomatid glycosome assembly is a promising new drug target. FEMS Microbiol Rev 2005; 28:603-43. [PMID: 15539076 DOI: 10.1016/j.femsre.2004.06.004] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2004] [Revised: 06/14/2004] [Accepted: 06/15/2004] [Indexed: 10/26/2022] Open
Abstract
In trypanosomatids (Trypanosoma and Leishmania), protozoa responsible for serious diseases of mankind in tropical and subtropical countries, core carbohydrate metabolism including glycolysis is compartmentalized in peculiar peroxisomes called glycosomes. Proper biogenesis of these organelles and the correct sequestering of glycolytic enzymes are essential to these parasites. Biogenesis of glycosomes in trypanosomatids and that of peroxisomes in other eukaryotes, including the human host, occur via homologous processes involving proteins called peroxins, which exert their function through multiple, transient interactions with each other. Decreased expression of peroxins leads to death of trypanosomes. Peroxins show only a low level of sequence conservation. Therefore, it seems feasible to design compounds that will prevent interactions of proteins involved in biogenesis of trypanosomatid glycosomes without interfering with peroxisome formation in the human host cells. Such compounds would be suitable as lead drugs against trypanosomatid-borne diseases.
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Affiliation(s)
- Juliette Moyersoen
- Research Unit for Tropical Diseases, Christian de Duve Institute of Cellular Pathology and Laboratory of Biochemistry, Université Catholique de Louvain, ICP-TROP 74.39, Avenue Hippocrate 74, B-1200 Brussels, Belgium
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52
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Azema L, Claustre S, Alric I, Blonski C, Willson M, Perié J, Baltz T, Tetaud E, Bringaud F, Cottem D, Opperdoes FR, Barrett MP. Interaction of substituted hexose analogues with the Trypanosoma brucei hexose transporter. Biochem Pharmacol 2004; 67:459-67. [PMID: 15037198 DOI: 10.1016/j.bcp.2003.09.005] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2003] [Accepted: 09/19/2003] [Indexed: 11/25/2022]
Abstract
Glucose metabolism is essential for survival of bloodstream form Trypanosoma brucei subspecies which cause human African trypanosomiasis (sleeping sickness). Hexose analogues may represent good compounds to inhibit glucose metabolism in these cells. Delivery of such compounds to the parasite is a major consideration in drug development. A series of D-glucose and D-fructose analogues were developed to explore the limits of the structure-activity relationship of the THT1 hexose transporter of bloodstream form African trypanosomes, a portal that might be exploited for drug uptake. D-glucose analogues with substituents at the C2 and C6 position continued to interact with the exofacial hexose binding site of the transporter. There was a limit to the size at C6 which still permitted recognition, although compounds carrying large groups at position C2 were still recognised. However, radiolabelled N-acetyl-D-[1-14C] glucosamine was not internalised by trypanosomes, in spite of the ability of this compound to inhibit glucose uptake, indicating that there is a limit to the size of C2 substituent that allows translocation. Addition of an alkylating group (bromoacetyl) at position C2 in the D-glucose series and at position 6 in the D-fructose set, created two analogues which interact with the transporter and kill trypanosomes in vitro. This indicates that inhibition of the transporter may be a good means of killing trypanosomes.
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Affiliation(s)
- Laurent Azema
- Groupe de Chimie Organique Biologique, Laboratoire de Synthèse et Physico Chimie de Molécules d'Intérêt Biologique, Université Paul Sabatier, UMR-5068-CNRS, Bât IIR1 118 route de Narbonne, 31062 Toulouse Cedex, France
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53
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Ladame S, Castilho MS, Silva CHTP, Denier C, Hannaert V, Périé J, Oliva G, Willson M. Crystal structure of Trypanosoma cruzi glyceraldehyde-3-phosphate dehydrogenase complexed with an analogue of 1,3-bisphospho-d-glyceric acid. ACTA ACUST UNITED AC 2004; 270:4574-86. [PMID: 14622286 DOI: 10.1046/j.1432-1033.2003.03857.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We report here the first crystal structure of a stable isosteric analogue of 1,3-bisphospho-d-glyceric acid (1,3-BPGA) bound to the catalytic domain of Trypanosoma cruzi glycosomal glyceraldehyde-3-phosphate dehydrogenase (gGAPDH) in which the two phosphoryl moieties interact with Arg249. This complex possibly illustrates a step of the catalytic process by which Arg249 may induce compression of the product formed, allowing its expulsion from the active site. Structural modifications were introduced into this isosteric analogue and the respective inhibitory effects of the resulting diphosphorylated compounds on T. cruzi and Trypanosoma brucei gGAPDHs were investigated by enzymatic inhibition studies, fluorescence spectroscopy, site-directed mutagenesis, and molecular modelling. Despite the high homology between the two trypanomastid gGAPDHs (> 95%), we have identified specific interactions that could be used to design selective irreversible inhibitors against T. cruzi gGAPDH.
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Affiliation(s)
- Sylvain Ladame
- Laboratoire de Synthèse et de Physico-Chimie de Molécules d'Intérêt Biologique UMR-CNRS 5068, Université Paul Sabatier, Toulouse, France.
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54
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Abstract
The trypanosomiases consist of a group of important animal and human diseases caused by parasitic protozoa of the genus Trypanosoma. In sub-Saharan Africa, the final decade of the 20th century witnessed an alarming resurgence in sleeping sickness (human African trypanosomiasis). In South and Central America, Chagas' disease (American trypanosomiasis) remains one of the most prevalent infectious diseases. Arthropod vectors transmit African and American trypanosomiases, and disease containment through insect control programmes is an achievable goal. Chemotherapy is available for both diseases, but existing drugs are far from ideal. The trypanosomes are some of the earliest diverging members of the Eukaryotae and share several biochemical peculiarities that have stimulated research into new drug targets. However, differences in the ways in which trypanosome species interact with their hosts have frustrated efforts to design drugs effective against both species. Growth in recognition of these neglected diseases might result in progress towards control through increased funding for drug development and vector elimination.
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Affiliation(s)
- Michael P Barrett
- Division of Infection and Immunity, Institute of Biomedical and Life Sciences, Joseph Black Building, University of Glasgow, G12 8QQ, Glasgow, UK.
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55
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Abstract
The discovery and optimization of antiparasitic compounds has profited by information-based methods newly emerged in the modern drug development process. The generation of computer models enables the cost-efficient and fast computational screening of virtual compound libraries for biologically active molecules. Two sources of information are available: structure-based drug design utilizes information about the disease target. We describe two different computational approaches, realized as the fast, flexible docking program FlexX and as the de novo design program LUDI. Ligand-based drug design, on the other hand, requires the structures and experimental data from biologically active compounds. Parasitic targets and antiparasitic compounds studied by various information-based methods include trypanosomal trypanothione reductase, antiprotozoal bisphosphonates, and trypanosomal glycosomal glyceraldehyde-3-phosphate dehydrogenase.
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Affiliation(s)
- Kristina Wolf
- 4SC AG, Am Klopferspitz 19a, 82152 Martinsried, Germany
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56
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Choe J, Guerra D, Michels PAM, Hol WGJ. Leishmania mexicana glycerol-3-phosphate dehydrogenase showed conformational changes upon binding a bi-substrate adduct. J Mol Biol 2003; 329:335-49. [PMID: 12758080 DOI: 10.1016/s0022-2836(03)00421-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Certain pathogenic trypanosomatids are highly dependent on glycolysis for ATP production, and hence their glycolytic enzymes, including glycerol-3-phosphate dehydrogenase (GPDH), are considered attractive drug targets. The ternary complex structure of Leishmania mexicana GPDH (LmGPDH) with dihydroxyacetone phosphate (DHAP) and NAD(+) was determined to 1.9A resolution as a further step towards understanding this enzyme's mode of action. When compared with the apo and binary complex structures, the ternary complex structure shows an 11 degrees hinge-bending motion of the C-terminal domain with respect to the N-terminal domain. In addition, residues in the C-terminal domain involved in catalysis or substrates binding show significant movements and a previously invisible five-residue loop region becomes well ordered and participates in NAD(+) binding. Unexpectedly, DHAP and NAD(+) appear to form a covalent bond, producing an adduct in the active site of LmGPDH. Modeling a ternary complex glycerol 3-phosphate (G3P) and NAD(+) with LmGPDH identified ten active site residues that are highly conserved among all GPDHs. Two lysine residues, Lys125 and Lys210, that are presumed to be critical in catalysis, were mutated resulting in greatly reduced catalytic activity. Comparison with other structurally related enzymes found by the program DALI suggested Lys210 as a key catalytic residue, which is located on a structurally conserved alpha-helix. From the results of site-directed mutagenesis, molecular modeling and comparison with related dehydrogenases, a catalytic mechanism of LmGPDH and a possible evolutionary scenario of this group of dehydrogenases are proposed.
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Affiliation(s)
- Jungwoo Choe
- Department of Biochemistry, Biomolecular Structure and Design program, University of Washington, Seattle 98195-7742, USA
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57
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Hillisch A, Hilgenfeld R. The role of protein 3D-structures in the drug discovery process. EXS 2003:157-81. [PMID: 12613176 DOI: 10.1007/978-3-0348-7997-2_8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/20/2023]
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58
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Choe J, Suresh S, Wisedchaisri G, Kennedy KJ, Gelb MH, Hol WGJ. Anomalous differences of light elements in determining precise binding modes of ligands to glycerol-3-phosphate dehydrogenase. CHEMISTRY & BIOLOGY 2002; 9:1189-97. [PMID: 12445769 DOI: 10.1016/s1074-5521(02)00243-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Pathogenic protozoa such as Trypanosome and Leishmania species cause tremendous suffering worldwide. Because of their dependence on glycolysis for energy, the glycolytic enzymes of these organisms, including glycerol-3-phosphate dehydrogenase (GPDH), are considered attractive drug targets. Using the adenine part of NAD as a lead compound, several 2,6-disubstituted purines were synthesized as inhibitors of Leishmania mexicana GPDH (LmGPDH). The electron densities for the inhibitor 2-bromo-6-chloro-purine bound to LmGPDH using a "conventional" wavelength around 1 A displayed a quasisymmetric shape. The anomalous signals from data collected at 1.77 A clearly indicated the positions of the halogen atoms and revealed the multiple binding modes of this inhibitor. Intriguing differences in the observed binding modes of the inhibitor between very similarly prepared crystals illustrate the possibility of crystal-to-crystal variations in protein-ligand complex structures.
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Affiliation(s)
- Jungwoo Choe
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
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59
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Pavão F, Castilho MS, Pupo MT, Dias RLA, Correa AG, Fernandes JB, da Silva MFGF, Mafezoli J, Vieira PC, Oliva G. Structure of Trypanosoma cruzi glycosomal glyceraldehyde-3-phosphate dehydrogenase complexed with chalepin, a natural product inhibitor, at 1.95 A resolution. FEBS Lett 2002; 520:13-7. [PMID: 12044862 DOI: 10.1016/s0014-5793(02)02700-x] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The structure of the glycosomal glyceraldehyde-3-phosphate dehydrogenase (gGAPDH) from Trypanosoma cruzi complexed with chalepin, a natural product from Pilocarpus spicatus, has been determined by X-ray crystallography to 1.95 A resolution. The structure is in the apo form without cofactors in the subunits of the tetrameric gGAPDH in the asymmetric unit. Unequivocal density corresponding to the inhibitor was clearly identified in one monomer. The final refined model of the complex shows extensive conformational changes when compared with the native structure. The mode of binding of chalepin to gGAPDH and its implications for inhibitor design are discussed.
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Affiliation(s)
- F Pavão
- Instituto de Química de São Carlos, USP, São Carlos, SP, Brazil
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60
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Zubrzycki IZ. Homology modeling and molecular dynamics study of NAD-dependent glycerol-3-phosphate dehydrogenase from Trypanosoma brucei rhodesiense, a potential target enzyme for anti-sleeping sickness drug development. Biophys J 2002; 82:2906-15. [PMID: 12023213 PMCID: PMC1302078 DOI: 10.1016/s0006-3495(02)75631-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Sleeping sickness and Chagas disease are among the most severe diseases in Africa as well as Latin America. These two diseases are caused by Trypanosoma spp. Recently, an enzyme of a glycolytic pathway, NAD-dependent glycerol-3-phosphate dehydrogenase, of Leishmania mexicana was crystallized and its structure determined by x-ray crystallography. This structure has offered an excellent template for modeling of the homologous enzymes from another Trypanosoma species. Here, a homology model of the T. brucei enzyme based on the x-ray structure of LmGPDH has been generated. This model was used as the starting point for molecular dynamics simulation in a water box. The analysis of the molecular dynamics trajectory indicates that the functionally important motifs have both a very stable secondary structure and tertiary arrangement.
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Affiliation(s)
- Igor Z Zubrzycki
- Department of Biochemistry and Microbiology, Rhodes University, Grahamstown 6140, South Africa.
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61
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Moore SA, Ronimus RS, Roberson RS, Morgan HW. The structure of a pyrophosphate-dependent phosphofructokinase from the Lyme disease spirochete Borrelia burgdorferi. Structure 2002; 10:659-71. [PMID: 12015149 DOI: 10.1016/s0969-2126(02)00760-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The structure of the 60 kDa pyrophosphate (PP(i))-dependent phosphofructokinase (PFK) from Borrelia burgdorferi has been solved and refined (R(free) = 0.243) at 2.55 A resolution. The domain structure of eubacterial ATP-dependent PFKs is conserved in B. burgdorferi PFK, and there are three large insertions relative to E. coli PFK, including a helical domain containing a hairpin structure that interacts with the active site. Asp177, conserved in all PP(i) PFKs, negates the binding of the alpha-phosphate group of ATP and likely contacts the essential Mg(2+) cation via a water molecule. Asn181 blocks the binding of the adenine moiety of ATP. Lys203 hydrogen bonds to a sulfate anion that likely mimics PP(i) substrate binding.
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Affiliation(s)
- Stanley A Moore
- Institute of Molecular Biosciences and Allan Wilson Centre for Molecular Ecology and Evolution, Massey University, Palmerston North, New Zealand.
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62
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Golisade A, Herforth C, Quirijnen L, Maes L, Link A. Improving an antitrypanosomal lead applying nucleophilic substitution on a safety catch linker. Bioorg Med Chem 2002; 10:159-65. [PMID: 11738617 DOI: 10.1016/s0968-0896(01)00253-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
In a joint effort with various laboratories we have been aiming at the structure-based design of glycolysis inhibitors as anti-trypanosomal drugs. 2'-Deoxy-2'-(3-methoxybenzamido)-N(6)-(1-naphtylmethyl)adenosine (1a) was thus revealed as a promising lead structure for the development of selective agents against protozoan parasites. Here we describe the polymer-assisted synthesis of novel amido derivatives of the scaffold 2'-amino-2'-deoxy-N(6)-(1-naphtylmethyl)adenosine (5a) we reported recently. This building block synthesized in solution was treated with an excess of polymer-supported carboxylic acids leading to chemoselective, practically quantitative conversion of the amine to the desired analogous amides. The best compound (1h) from this series was obtained after on-bead nucleophilic substitution of the carboxylic acid equivalent attached to the Kenner safety catch linker and exhibited an improved inhibitory effect on T. b. brucei blood stream forms with an IC(50) of 0.85 microM in vitro
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Affiliation(s)
- Abolfasl Golisade
- Institut für Pharmazie, Abteilung für Pharmazeutische Chemie, Universität Hamburg, Bundesstrasse 45, D-20146, Hamburg, Germany
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63
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Abstract
Peroxisomes of higher eukaryotes, glycosomes of kinetoplastids, and glyoxysomes of plants are related microbody organelles that perform differing metabolic functions tailored to their cellular environments. The close evolutionary relationship of these organelles is most clearly evidenced by the conservation of proteins involved in matrix protein import and biogenesis. The glycosome can be viewed as an offshoot of the peroxisomal lineage with additional metabolic functions, specifically glycolysis and purine salvage. Within the parasitic protozoa, only kinetoplastids have been conclusively demonstrated to possess glycosomes or indeed any peroxisome-like organelle. The importance of glycosomal pathways and their compartmentation emphasizes the potential of the glycosome and glycosomal proteins as drug targets.
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Affiliation(s)
- M Parsons
- Seattle Biomedical Research Institute, 4 Nickerson St., 98177, Seattle, WA, USA.
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64
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Aronov AM, Munagala NR, Kuntz ID, Wang CC. Virtual screening of combinatorial libraries across a gene family: in search of inhibitors of Giardia lamblia guanine phosphoribosyltransferase. Antimicrob Agents Chemother 2001; 45:2571-6. [PMID: 11502531 PMCID: PMC90694 DOI: 10.1128/aac.45.9.2571-2576.2001] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2001] [Accepted: 06/18/2001] [Indexed: 11/20/2022] Open
Abstract
Parasitic protozoa lack the ability to synthesize purine nucleotides de novo, relying instead on purine salvage enzymes for their survival. Guanine phosphoribosyltransferase (GPRT) from the protozoan parasite Giardia lamblia is a potential target for rational antiparasitic drug design, based on the experimental evidence, which indicates the lack of interconversion between adenine and guanine nucleotide pools. The present study is a continuation of our efforts to use three-dimensional structures of parasitic phosphoribosyltransferases (PRTs) to design novel antiparasitic agents. Two micromolar phthalimide-based GPRT inhibitors were identified by screening the in-house phthalimide library. A combination of structure-based scaffold selection using virtual library screening across the PRT gene family and solid phase library synthesis led to identification of smaller (molecular weight, <300) ligands with moderate to low specificity for GPRT; the best inhibitors, GP3 and GP5, had K(i) values in the 23 to 25 microM range. These results represent significant progress toward the goal of designing potent inhibitors of purine salvage in Giardia parasites. As a second step in this process, altering the phthalimide moiety to optimize interactions in the guanine-binding pocket of GPRT is expected to lead to compounds with promising activity against G. lamblia PRT.
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Affiliation(s)
- A M Aronov
- Department of Pharmaceutical Chemistry, University of California, San Francisco, California 94143-0446, USA
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65
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Seed JR, Black SJ. The classic paper of Tobie, von Brand, and Mehlman (1950) revisited. J Parasitol 2001; 87:718-20. [PMID: 11534631 DOI: 10.1645/0022-3395(2001)087[0718:tcpotv]2.0.co;2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Affiliation(s)
- J R Seed
- Department of Epidemiology, School of Public Health, University of North Carolina, Chapel Hill 27599-7400, USA
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66
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Bressi JC, Verlinde CLMJ, Aronov AM, Shaw ML, Shin SS, Nguyen LN, Suresh S, Buckner FS, Van Voorhis WC, Kuntz ID, Hol WGJ, Gelb MH. Adenosine analogues as selective inhibitors of glyceraldehyde-3-phosphate dehydrogenase of Trypanosomatidae via structure-based drug design. J Med Chem 2001; 44:2080-93. [PMID: 11405646 PMCID: PMC2957370 DOI: 10.1021/jm000472o] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In our continuation of the structure-based design of anti-trypanosomatid drugs, parasite-selective adenosine analogues were identified as low micromolar inhibitors of glyceraldehyde-3-phosphate dehydrogenase (GAPDH). Crystal structures of Trypanosoma brucei, Trypanosoma cruzi, Leishmania mexicana, and human GAPDH's provided details of how the adenosyl moiety of NAD(+) interacts with the proteins, and this facilitated the understanding of the relative affinities of a series of adenosine analogues for the various GAPDH's. From exploration of modifications of the naphthalenemethyl and benzamide substituents of a lead compound, N(6)-(1-naphthalenemethyl)-2'-deoxy-2'-(3-methoxybenzamido)adenosine (6e), N(6)-(substituted-naphthalenemethyl)-2'-deoxy-2'-(substituted-benzamido)adenosine analogues were investigated. N(6)-(1-Naphthalenemethyl)-2'-deoxy-2'-(3,5-dimethoxybenzamido)adenosine (6m), N(6)-[1-(3-hydroxynaphthalene)methyl]-2'-deoxy-2'-(3,5-dimethoxybenzamido)adenosine (7m), N(6)-[1-(3-methoxynaphthalene)methyl]-2'-deoxy-2'-(3,5-dimethoxybenzamido)adenosine (9m), N(6)-(2-naphthalenemethyl)-2'-deoxy-2'-(3-methoxybenzamido)adenosine (11e), and N(6)-(2-naphthalenemethyl)-2'-deoxy-2'-(3,5-dimethoxybenzamido)adenosine (11m) demonstrated a 2- to 3-fold improvement over 6e and a 7100- to 25000-fold improvement over the adenosine template. IC(50)'s of these compounds were in the range 2-12 microM for T. brucei, T. cruzi, and L. mexicana GAPDH's, and these compounds did not inhibit mammalian GAPDH when tested at their solubility limit. To explore more thoroughly the structure-activity relationships of this class of compounds, a library of 240 N(6)-(substituted)-2'-deoxy-2'-(amido)adenosine analogues was generated using parallel solution-phase synthesis with N(6) and C2' substituents chosen on the basis of computational docking scores. This resulted in the identification of 40 additional compounds that inhibit parasite GAPDH's in the low micromolar range. We also explored adenosine analogues containing 5'-amido substituents and found that 2',5'-dideoxy-2'-(3,5-dimethoxybenzamido)-5'-(diphenylacetamido)adenosine (49) displays an IC(50) of 60-100 microM against the three parasite GAPDH's.
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Affiliation(s)
- Jerome C. Bressi
- Department of Chemistry, University of Washington, Seattle, Washington 98195
| | | | - Alex M. Aronov
- Department of Pharmaceutical Chemistry, University of California, San Francisco, California 94143
| | - My Le Shaw
- Department of Biochemistry, University of Washington, Seattle, Washington 98195
| | - Sam S. Shin
- Department of Chemistry, University of Washington, Seattle, Washington 98195
| | - Lisa N. Nguyen
- Department of Medicine, University of Washington, Seattle, Washington 98195
| | - Stephen Suresh
- Department of Biological Structure, University of Washington, Seattle, Washington 98195
- Biomolecular Structure Center and Howard Hughes Medical Institute, Seattle, Washington 98195
| | | | | | - Irwin D. Kuntz
- Department of Pharmaceutical Chemistry, University of California, San Francisco, California 94143
| | - Wim G. J. Hol
- Department of Biological Structure, University of Washington, Seattle, Washington 98195
- Department of Biochemistry, University of Washington, Seattle, Washington 98195
- Biomolecular Structure Center and Howard Hughes Medical Institute, Seattle, Washington 98195
| | - Michael H. Gelb
- Department of Chemistry, University of Washington, Seattle, Washington 98195
- Department of Biochemistry, University of Washington, Seattle, Washington 98195
- To whom correspondence should be addressed. Phone: 206-543-7142. Fax: 206-685-8665.
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67
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Suresh S, Bressi JC, Kennedy KJ, Verlinde CL, Gelb MH, Hol WG. Conformational changes in Leishmania mexicana glyceraldehyde-3-phosphate dehydrogenase induced by designed inhibitors. J Mol Biol 2001; 309:423-35. [PMID: 11371162 DOI: 10.1006/jmbi.2001.4588] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The glycolytic enzymes of trypanosomes are attractive drug targets, since the blood-stream form of Trypanosoma brucei lacks a functional citric acid cycle and is dependent solely on glycolysis for its energy requirements. Glyceraldehyde-3-phosphate dehydrogenases (GAPDH) from the pathogenic trypanosomatids T. brucei, Trypanosoma cruzi and Leishmania mexicana are quite similar to each other, and yet have sufficient structural differences compared to the human enzyme to enable the structure-based design of compounds that selectively inhibit all three trypanosomatid enzymes but not the human homologue. Adenosine analogs with substitutions on N-6 of the adenine ring and on the 2' position of the ribose moiety were designed, synthesized and tested for inhibition. Two crystal structures of L. mexicana glyceraldehyde-3-phosphate dehydrogenase in complex with high-affinity inhibitors that also block parasite growth were solved at a resolution of 2.6 A and 3.0 A. The complexes crystallized in the same crystal form, with one and a half tetramers in the crystallographic asymmetric unit. There is clear electron density for the inhibitor in all six copies of the binding site in each of the two structures. The L. mexicana GAPDH subunit exhibits substantial structural plasticity upon binding the inhibitor. Movements of the protein backbone, in response to inhibitor binding, enlarge a cavity at the binding site to accommodate the inhibitor in a classic example of induced fit. The extensive hydrophobic interactions between the protein and the two substituents on the adenine scaffold of the inhibitor provide a plausible explanation for the high affinity of these inhibitors for trypanosomatid GAPDHs.
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Affiliation(s)
- S Suresh
- Departments of Biological Structure, Biomolecular Structure Center, Howard Hughes Medical Institute, Seattle, WA 98915, USA
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68
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Seed JR. African trypanosomiasis research: 100 years of progress, but questions and problems still remain. Int J Parasitol 2001; 31:434-42. [PMID: 11334927 DOI: 10.1016/s0020-7519(01)00142-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Past and present progress in our understanding of African trypanosomiasis is briefly reviewed. Although tremendous scientific strides have been achieved, an epidemic of the disease is currently underway. Three areas of research which are believed necessary for the control of African trypanosomiasis are discussed. It is suggested that a better understanding of the host-parasite relationship is essential; more emphasis and a broader approach to drug development is required; and finally, further research into the socio-economic aspects of African trypanosomiasis is urgently needed before the human disease can again be controlled.
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Affiliation(s)
- J R Seed
- Department of Epidemiology, School of Public Health, University of North Carolina, CB#7400, McGavran-Greenberg Hall, 27599-7400, Chapel Hill, NC, USA.
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69
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Abstract
The potential for chemotherapeutic exploitation of carbohydrate metabolism in the Trypanosomatidae is reviewed. This review is based largely on discussions held at a meeting of the COST B9 Action, entitled 'Bioenergetics of Protozoan Parasites'. The major questions posed were: which enzymes are the best to target; what further information is required to allow their use for rational drug development; what compounds would constitute the best inhibitors and which of the enzymes of the pentose-phosphate pathway are present inside the glycosomes, as well? Only partial answers could be obtained in many cases, but the interactive discussion between the multidisciplinary group of participants, comprising chemists, biochemists and molecular biologists, provided thought-provoking ideas and will help direct future research.
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Affiliation(s)
- F R Opperdoes
- Christian de Duve Institute of Cellular Pathology, ICP-TROP 74/39, Avenue Hippocrate 74, B-1200, Brussels, Belgium.
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70
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Ladame S, Bardet M, Périé J, Willson M. Selective inhibition of Trypanosoma brucei GAPDH by 1,3-bisphospho-D-glyceric acid (1,3-diPG) analogues. Bioorg Med Chem 2001; 9:773-83. [PMID: 11310612 DOI: 10.1016/s0968-0896(00)00295-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Various phosphono-phosphates and diphosphonates were synthesized as 1,3-diphosphoglycerate (1,3-diPG) analogues by using a beta-ketophosphonate, an alpha-fluoro,beta-ketophosphonate or a beta-ketophosphoramidate to mimic the unstable carboxyphosphate part of the natural substrate. The inhibitory effect of these analogues on glyceraldehyde-3-phosphate dehydrogenases (GAPDH) from Trypanosoma brucei (Tb) and rabbit muscle were measured with respect to both substrates, glyceraldehyde-3-phosphate (GAP) and 1,3-diPG. Interestingly, all 1,5-diphosphono,2-oxopentanes without substitution at the C-3 position selectively inhibit the Tb GAPDH with respect to 1,3-diPG and are without effect on Rm GAPDH. All 1-phospho,3-oxo,4-phosphonobutanes show themselves to be non-selective inhibitors either with regard to substrates or organisms, but they will be of a great interest as 1,3-diPG stable models for structural studies of co-crystals with GAPDHs.
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Affiliation(s)
- S Ladame
- Groupe de Chimie Organique Biologique, LSPCMIB, UMR CNRS 5068, Université Paul Sabatier, Toulouse, France
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71
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Hardré R, Salmon L, Opperdoes FR. Competitive inhibition of Trypanosoma brucei phosphoglucose isomerase by D-arabinose-5-phosphate derivatives. JOURNAL OF ENZYME INHIBITION 2001; 15:509-15. [PMID: 11030090 DOI: 10.3109/14756360009040706] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
We report four new strong high energy intermediate analog competitive inhibitors of fructose-6-phosphate isomerization catalyzed by purified Trypanosoma brucei phosphoglucose isomerase: D-arabinonhydroxamic acid-5-phosphate, D-arabinonate-5-phosphate, D-arabinonamide-5-phosphate and D-arabinonhydrazide-5-phosphate. For comparison, the inhibitory properties of the corresponding non-phosphorylated analogues D-arabinonhydroxamic acid, D-arabinonate, D-arabinonamide and D-arabinonhydrazide were also evaluated. D-Arabinonhydroxamic acid-5-phosphate appears as the most potent competitive inhibitor ever evaluated on a phosphoglucose isomerase with an inhibition constant value of 50 nM and a Michaelis constant over inhibition constant ratio of about 2000. Our results show that anionic high energy intermediate analogues, and more particularly D-arabinonhydroxamic acid-5-phosphate, display a weak but significant specificity for Trypanosoma brucei phosphoglucose isomerase versus yeast phosphoglucose isomerase, while neutral high energy intermediate analogues are not selective at all. This would indicate the presence of more positively charged residues in the active site for Trypanosoma brucei phosphoglucose isomerase as compared to that of yeast phosphoglucose isomerase.
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Affiliation(s)
- R Hardré
- Laboratoire de Chimie Bioorganique et Bioinorganique, ERS 1824, Institute de Chimie Moléculaire d'Orsay, Université de Paris-Sud, France
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72
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Verlinde CL, Hannaert V, Blonski C, Willson M, Périé JJ, Fothergill-Gilmore LA, Opperdoes FR, Gelb MH, Hol WG, Michels PA. Glycolysis as a target for the design of new anti-trypanosome drugs. Drug Resist Updat 2001; 4:50-65. [PMID: 11512153 DOI: 10.1054/drup.2000.0177] [Citation(s) in RCA: 170] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Glycolysis is perceived as a promising target for new drugs against parasitic trypanosomatid protozoa because this pathway plays an essential role in their ATP supply. Trypanosomatid glycolysis is unique in that it is compartmentalized, and many of its enzymes display unique structural and kinetic features. Structure- and catalytic mechanism-based approaches are applied to design compounds that inhibit the glycolytic enzymes of the parasites without affecting the corresponding proteins of the human host. For some trypanosomatid enzymes, potent and selective inhibitors have already been developed that affect only the growth of cultured trypanosomatids, and not mammalian cells.
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Affiliation(s)
- C L Verlinde
- Department of Biological Structure, Biomolecular Structure Center, University of Washington, Seattle, USA
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73
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Su AI, Lorber DM, Weston GS, Baase WA, Matthews BW, Shoichet BK. Docking molecules by families to increase the diversity of hits in database screens: computational strategy and experimental evaluation. Proteins 2001; 42:279-93. [PMID: 11119652 DOI: 10.1002/1097-0134(20010201)42:2<279::aid-prot150>3.0.co;2-u] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Molecular docking programs screen chemical databases for novel ligands that fit protein binding sites. When one compound fits the site well, close analogs typically do the same. Therefore, many of the compounds that are found in such screens resemble one another. This reduces the variety and novelty of the compounds suggested. In an attempt to increase the diversity of docking hit lists, the Available Chemicals Directory was grouped into families of related structures. All members of every family were docked and scored, but only the best scoring molecule of a high-ranking family was allowed in the hit list. The identity and scores of the other members of these families were recorded as annotations to the best family member, but they were not independently ranked. This family-based docking method was compared with molecule-by-molecule docking in screens against the structures of thymidylate synthase, dihydrofolate reductase (DHFR), and the cavity site of the mutant T4 lysozyme Leu99 --> Ala (L99A). In each case, the diversity of the hit list increased, and more families of known ligands were found. To investigate whether the newly identified hits were sensible, we tested representative examples experimentally for binding to L99A and DHFR. Of the six compounds tested against L99A, five bound to the internal cavity. Of the seven compounds tested against DHFR, six inhibited the enzyme with apparent K(i) values between 0.26 and 100 microM. The segregation of potential ligands into families of related molecules is a simple technique to increase the diversity of candidates suggested by database screens. The general approach should be applicable to most docking methods. Proteins 2001;42:279-293.
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Affiliation(s)
- A I Su
- Department of Molecular Pharmacology & Biological Chemistry, Northwestern University, Chicago, Illinois 60611-3008, USA
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74
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Kennedy KJ, Bressi JC, Gelb MH. A disubstituted NAD+ analogue is a nanomolar inhibitor of trypanosomal glyceraldehyde-3-phosphate dehydrogenase. Bioorg Med Chem Lett 2001; 11:95-8. [PMID: 11206479 DOI: 10.1016/s0960-894x(00)00608-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
N6-Naphthalenemethyl-2'-methoxybenzamido-beta-NAD+, a derivative of a low micromolar first-generation inhibitor of trypanosomal glyceraldehyde phosphate dehydrogenase (GAPDH), was synthesized, taking advantage of methodology for the selective phosphitylation of nucleosides. The compound was found to be a poor alternate cosubstrate for GAPDH, but an extremely potent inhibitor. Although intended for use in crystallization trials, the analogue presents possibilities for further drug design.
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Affiliation(s)
- K J Kennedy
- Department of Chemistry, University of Washington, Seattle 98195, USA
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75
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Kita K, Miyadera H, Saruta F, Miyoshi H. Parasite Mitochondria as a Target for Chemotherapy. ACTA ACUST UNITED AC 2001. [DOI: 10.1248/jhs.47.219] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Kiyoshi Kita
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo
| | - Hiroko Miyadera
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo
| | - Fumiko Saruta
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo
| | - Hideto Miyoshi
- Division of Applied Life Science, Graduate School of Agriculture, Kyoto University
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76
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Keiser J, Stich A, Burri C. New drugs for the treatment of human African trypanosomiasis: research and development. Trends Parasitol 2001; 17:42-9. [PMID: 11137740 DOI: 10.1016/s1471-4922(00)01829-8] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Chemotherapy of human African trypanosomiasis is problematic because of the high frequency of severe adverse events, the long duration and high cost of treatment, and an increasing number of treatment-refractory cases. New cost-efficient, easy-to-use drugs are urgently needed. Whereas basic research on potential drug targets is anchored in academia, the complex, highly regulated and very expensive process of preclinical and clinical drug development is almost exclusively in the hands of pharmaceutical companies. Jennifer Keiser, August Stich and Christian Burri here review, from the angle of industrial drug research and development, the past ten years of research activities at different stages of the development of trypanocidal drugs, and assess future prospects. The absence of compounds in clinical development Phases I-III indicates no new drugs will become available in the next few years.
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Affiliation(s)
- J Keiser
- Swiss Tropical Institute, PO Box, CH-4002, Basel, Switzerland
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77
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Abstract
Problems associated with the current therapies of sleeping sickness include toxicity, resistance and a lack of a guaranteed supply. However, no new formulations are close to gaining a licence for clinical use and relatively few compounds have been shown to be effective in experimental systems. Many potentially good biochemical targets for drugs have been identified. Some of these have been validated and lead compounds have been developed. However, the biology of trypanosomes means that various pharmacological demands must be met in developing new trypanocides for clinical use. Foremost among these problems is the blood-brain barrier, across which trypanocides must cross to reach parasites in the cerebrospinal fluid.The principal problem, however, relates not to biological difficulties, which are technically surmountable, but to economics. Put simply, most representatives of the pharmaceutical industry believe that selling drugs to the victims of sleeping sickness will not yield sufficient income to justify expenses needed for the development of novel reagents. Only when this economic barrier can be lowered will new drugs emerge for use against sleeping sickness.
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Affiliation(s)
- Michael P. Barrett
- Institute of Biomedical and Life Sciences, Division of Infection & Immunity, The University of Glasgow, Glasgow, UK
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78
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Bressi JC, Choe J, Hough MT, Buckner FS, Van Voorhis WC, Verlinde CL, Hol WG, Gelb MH. Adenosine analogues as inhibitors of Trypanosoma brucei phosphoglycerate kinase: elucidation of a novel binding mode for a 2-amino-N(6)-substituted adenosine. J Med Chem 2000; 43:4135-50. [PMID: 11063610 DOI: 10.1021/jm000287a] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
As part of a project aimed at structure-based design of adenosine analogues as drugs against African trypanosomiasis, N(6)-, 2-amino-N(6)-, and N(2)-substituted adenosine analogues were synthesized and tested to establish structure-activity relationships for inhibiting Trypanosoma brucei glycosomal phosphoglycerate kinase (PGK), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and glycerol-3-phosphate dehydrogenase (GPDH). Evaluation of X-ray structures of parasite PGK, GAPDH, and GPDH complexed with their adenosyl-bearing substrates led us to generate a series of adenosine analogues which would target all three enzymes simultaneously. There was a modest preference by PGK for N(6)-substituted analogues bearing the 2-amino group. The best compound in this series, 2-amino-N(6)- [2''(p-hydroxyphenyl)ethyl]adenosine (46b), displayed a 23-fold improvement over adenosine with an IC(50) of 130 microM. 2-[[2''-(p-Hydroxyphenyl)ethyl]amino]adenosine (46c) was a weak inhibitor of T. brucei PGK with an IC(50) of 500 microM. To explore the potential of an additive effect that having the N(6) and N(2) substitutions in one molecule might provide, the best ligands from the two series were incorporated into N(6),N(2)-disubstituted adenosine analogues to yield N(6)-(2''-phenylethyl)-2-[(2'' -phenylethyl)amino]adenosine (69) as a 30 microM inhibitor of T. brucei PGK which is 100-fold more potent than the adenosine template. In contrast, these series gave no compounds that inhibited parasitic GAPDH or GPDH more than 10-20% when tested at 1.0 mM. A 3.0 A X-ray structure of a T. brucei PGK/46b complex revealed a binding mode in which the nucleoside analogue was flipped and the ribosyl moiety adopted a syn conformation as compared with the previously determined binding mode of ADP. Molecular docking experiments using QXP and SAS program suites reproduced this "flipped and rotated" binding mode.
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Affiliation(s)
- J C Bressi
- Department of Chemistry, University of Washington, Seattle, 98195, USA
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79
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Golisade A, Bressi JC, Van Calenbergh S, Gelb MH, Link A. Polymer-assisted solution-phase synthesis of 2'-amido-2'-deoxyadenosine derivatives targeted at the NAD(+)-binding sites of parasite enzymes. JOURNAL OF COMBINATORIAL CHEMISTRY 2000; 2:537-44. [PMID: 11029179 DOI: 10.1021/cc0000343] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A polymer-assisted solution-phase (PASP) synthesis of lead structure analogues ready for biological testing without the demand for chromatographic purification is described. Carboxylic acids are coupled to the Kenner or Ellman safety catch linker, respectively, activated by methylation or cyanomethylation and subsequently transferred to the 2'-amino group of the 2'-amino-2'-deoxyadenosine scaffold (5). The chemoselective attack of weakly nucleophilic amino groups on the N-alkylated N-acyl sulfonamide linker allows for the synthesis of amides 6 in high yields without the need for protection of primary and secondary hydroxyl functions. Thus, the use of 4-sulfamylbenzoylaminomethyl polystyrene is reported for the construction of chemoselective polymer-supported acylating reagents instead of its known use as linker in solid-phase peptide or organic synthesis. This approach is demonstrated to be well suited to obtain 2'-amido-2'-deoxyadenosine derivatives 6 in parallel format. Biological evaluation of all compounds reported revealed no improvement over known lead structures.
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Affiliation(s)
- A Golisade
- Institut für Pharmazie, Fachbereich Chemie, Universität Hamburg, Bundesstrasse 45, D-20146 Hamburg, Germany
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80
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Abstract
Two approaches to structure-based drug design, that is, the docking of known compounds into a target protein and molecular assembly in situ, are seen to be merging technologies. The need for structural information about drug-protein complexes is now fundamental for drug discovery.
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Affiliation(s)
- P J Gane
- De Novo Pharmaceuticals Ltd., Cambridge, UK.
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81
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Suresh S, Turley S, Opperdoes FR, Michels PA, Hol WG. A potential target enzyme for trypanocidal drugs revealed by the crystal structure of NAD-dependent glycerol-3-phosphate dehydrogenase from Leishmania mexicana. Structure 2000; 8:541-52. [PMID: 10801498 DOI: 10.1016/s0969-2126(00)00135-0] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND NAD-dependent glycerol-3-phosphate dehydrogenase (GPDH) catalyzes the interconversion of dihydroxyacetone phosphate and L-glycerol-3-phosphate. Although the enzyme has been characterized and cloned from a number of sources, until now no three-dimensional structure has been determined for this enzyme. Although the utility of this enzyme as a drug target against Leishmania mexicana is yet to be established, the critical role played by GPDH in the long slender bloodstream form of the related kinetoplastid Trypanosoma brucei makes it a viable drug target against sleeping sickness. RESULTS The 1.75 A crystal structure of apo GPDH from L. mexicana was determined by multiwavelength anomalous diffraction (MAD) techniques, and used to solve the 2.8 A holo structure in complex with NADH. Each 39 kDa subunit of the dimeric enzyme contains a 189-residue N-terminal NAD-binding domain and a 156-residue C-terminal substrate-binding domain. Significant parts of both domains share structural similarity with plant acetohydroxyacid isomeroreductase. The discovery of extra, fatty-acid like, density buried inside the C-terminal domain indicates a possible post-translational modification with an associated biological function. CONCLUSIONS The crystal structure of GPDH from L. mexicana is the first structure of this enzyme from any source and, in view of the sequence identity of 63%, serves as a valid model for the T. brucei enzyme. The differences between the human and trypanosomal enzymes are extensive, with only 29% sequence identity between the parasite and host enzyme, and support the feasibility of exploiting the NADH-binding site to develop selective inhibitors against trypanosomal GPDH. The structure also offers a plausible explanation for the observed inhibition of the T. brucei enzyme by melarsen oxide, the active form of the trypanocidal drugs melarsoprol and cymelarsan.
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Affiliation(s)
- S Suresh
- Department of Biological Structure, Biomolecular Structure Center, Howard Hughes Medical Institute, University of Washington, Seattle, WA 98195, USA
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82
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Golisade A, Van Calenbergh S, Link A. 2′-Amino-2′-deoxy-N6-(1-naphthylmethyl)adenosine as Novel Scaffold for a Polymer-Assisted Amidation Protocol. Tetrahedron 2000. [DOI: 10.1016/s0040-4020(00)00228-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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83
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Daubenberger CA, Pöltl-Frank F, Jiang G, Lipp J, Certa U, Pluschke G. Identification and recombinant expression of glyceraldehyde-3-phosphate dehydrogenase of Plasmodium falciparum. Gene 2000; 246:255-64. [PMID: 10767547 DOI: 10.1016/s0378-1119(00)00069-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The gene coding for the cytosolic glyceraldehyde-3-phosphate dehydrogenase (GAPDH; EC 1.2.1.12) was isolated from Plasmodium falciparum. The gene contains 1 intron and the A+T content is characteristic for the codon usage of P. falciparum. The predicted open reading frame codes for 337 amino acids (36651Da) and is 63.5% identical to the human erythrocytic GAPDH. GAPDH sequences from several field isolates of P. falciparum displayed 100% conservation. Phylogenetic analysis supports the hypothesis that dinoflagellates and Plasmodium are closely related. The protein encoded by the pfGAPDH was expressed recombinantly in Escherichia coli and exhibited enzymatic activity with NAD(+) but not with NADP(+) as cofactor. Antiserum raised against the recombinantly expressed enzyme detected specifically all developmental stages of cultured P. falciparum blood-stage parasites.
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Affiliation(s)
- C A Daubenberger
- Swiss Tropical Institute, Molecular Immunology, Socinstrasse 57, 4002, Basel, Switzerland.
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84
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Bakker BM, Westerhoff HV, Opperdoes FR, Michels PA. Metabolic control analysis of glycolysis in trypanosomes as an approach to improve selectivity and effectiveness of drugs. Mol Biochem Parasitol 2000; 106:1-10. [PMID: 10743606 DOI: 10.1016/s0166-6851(99)00197-8] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Glycolysis is the only ATP-generating process in bloodstream form trypanosomes and is therefore a promising drug target. Inhibitors which decrease significantly the glycolytic flux will kill the parasites. Both computer simulation and experimental studies of glycolysis in bloodstream form Trypanosoma brucei indicated that the control of the glycolytic flux is shared by several steps in the pathway. The results of these analyses provide quantitative information about the prospects of decreasing the flux by inhibition of any individual enzyme. The plasma membrane glucose transporter appears the most promising target from this perspective, followed by aldolase, glyceraldehyde-3-phosphate dehydrogenase, phosphoglycerate kinase and glycerol-3-phosphate dehydrogenase. Non-competitive or irreversible inhibitors would be most effective, but it is argued that potent competitive inhibitors can be suitable, provided that the concentration of the competing substrate cannot increase unrestrictedly. Such is the case for inhibitors that compete with coenzymes or with blood glucose.
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Affiliation(s)
- B M Bakker
- Kluyver Institute of Biotechnology, Delft University of Technology, The Netherlands
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85
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Bakker BM, Walsh MC, ter Kuile BH, Mensonides FI, Michels PA, Opperdoes FR, Westerhoff HV. Contribution of glucose transport to the control of the glycolytic flux in Trypanosoma brucei. Proc Natl Acad Sci U S A 1999; 96:10098-103. [PMID: 10468568 PMCID: PMC17848 DOI: 10.1073/pnas.96.18.10098] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The rate of glucose transport across the plasma membrane of the bloodstream form of Trypanosoma brucei was modulated by titration of the hexose transporter with the inhibitor phloretin, and the effect on the glycolytic flux was measured. A rapid glucose uptake assay was developed to measure the transport activity independently of the glycolytic flux. Phloretin proved a competitive inhibitor. When the effect of the intracellular glucose concentration on the inhibition was taken into account, the flux control coefficient of the glucose transporter was between 0.3 and 0.5 at 5 mM glucose. Because the flux control coefficients of all steps in a metabolic pathway sum to 1, this result proves that glucose transport is not the rate-limiting step of trypanosome glycolysis. Under physiological conditions, transport shares the control with other steps. At glucose concentrations much lower than physiological, the glucose carrier assumed all control, in close agreement with model predictions.
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Affiliation(s)
- B M Bakker
- Molecular Cell Physiology, BioCentrum Amsterdam, Vrije Universiteit, De Boelelaan 1087, NL-1081 HV Amsterdam, The Netherlands
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