151
|
Boss C, Corminboeuf O, Grisostomi C, Weller T. Inhibitors of aspartic proteases – potential antimalarial agents. Expert Opin Ther Pat 2006. [DOI: 10.1517/13543776.16.3.295] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
|
152
|
Martins TM, Domingos A, Berry C, Wyatt DM. The activity and inhibition of the food vacuole plasmepsin from the rodent malaria parasite Plasmodium chabaudi. Acta Trop 2006; 97:212-8. [PMID: 16329985 DOI: 10.1016/j.actatropica.2005.11.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2005] [Revised: 11/04/2005] [Accepted: 11/07/2005] [Indexed: 11/29/2022]
Abstract
The rodent malaria parasite Plasmodium chabaudi encodes one food vacuole plasmepsin-the aspartic proteinases important in haemoglobin degradation. A recombinant form of this enzyme was found to cleave a variety of peptide substrates and was susceptible to a selection of naturally occurring and synthetic inhibitors, displaying an inhibition profile distinct from that of aspartic proteinases from other malaria parasites. In addition, inhibitors of HIV proteinase that kill P. chabaudi in vivo were also inhibitors of this new plasmepsin. P. chabaudi is a widely used model for human malaria species and, therefore, the characterisation of this plasmepsin is an important contribution towards understanding its biology.
Collapse
Affiliation(s)
- Tiago M Martins
- Instituto Nacional de Engenharia, Tecnologia e Inovação, Departamento de Biotecnologia, UTPAM, Edifício F, Estrada do Paço do Lumiar, 1649-038 Lisboa, Portugal
| | | | | | | |
Collapse
|
153
|
Klemba M, Goldberg DE. Characterization of plasmepsin V, a membrane-bound aspartic protease homolog in the endoplasmic reticulum of Plasmodium falciparum. Mol Biochem Parasitol 2006; 143:183-91. [PMID: 16024107 DOI: 10.1016/j.molbiopara.2005.05.015] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2005] [Revised: 04/27/2005] [Accepted: 05/09/2005] [Indexed: 11/21/2022]
Abstract
Aspartic proteases participate in a wide variety of cellular processes in eukaryotic organisms. The genome of the human malaria parasite Plasmodium falciparum encodes 10 aspartic protease homologs. Functions have been assigned to four of these: plasmepsins I, II, IV and histo-aspartic protease are key players in the catabolism of hemoglobin in the food vacuole. The functions of the other six remain obscure. To better understand the roles of aspartic proteases in blood stage growth and asexual reproduction of P. falciparum, we have characterized the biosynthesis, cellular location and pepstatin-binding properties of plasmepsin V (PM V). PM V is expressed over the course of asexual intraerythrocytic development. The amount of PM V in the parasite is lowest in the ring stage and increases steadily through schizogony. The proregion of this aspartic protease homolog exhibits remarkable interspecies diversity and appears not to be removed following biosynthesis. In intraerythrocytic parasites, PM V is located in the endoplasmic reticulum but not in ERD2-associated Golgi structures. Fractionation and solubilization experiments demonstrate that PM V is an integral membrane protein, a result that is consistent with the presence of a C-terminal putative transmembrane domain in the PM V sequence. In contrast to the food vacuole plasmepsins, detergent-solubilized PM V does not bind the aspartic protease inhibitor pepstatin. Together, these results strongly suggest that the role of PM V in P. falciparum is distinct from those of previously characterized plasmepsins.
Collapse
Affiliation(s)
- Michael Klemba
- Department of Medicine and Molecular Microbiology, Howard Hughes Medical Institute, Washington University School of Medicine, 660 S. Euclid Ave., Box 8230, St. Louis, MO 63110, USA
| | | |
Collapse
|
154
|
Robert A, Bonduelle C, Laurent SAL, Meunier B. Heme alkylation by artemisinin and trioxaquines. J PHYS ORG CHEM 2006. [DOI: 10.1002/poc.1059] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
155
|
Binkert C, Frigerio M, Jones A, Meyer S, Pesenti C, Prade L, Viani F, Zanda M. Replacement of Isobutyl by Trifluoromethyl in Pepstatin A Selectively Affects Inhibition of Aspartic Proteinases. Chembiochem 2005; 7:181-6. [PMID: 16307463 DOI: 10.1002/cbic.200500180] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Two bis-trifluoromethyl pepstatin A analogues, carboxylic acid 1 and its methyl ester 2, have been synthesised in order to probe the properties and size of the trifluoromethyl (Tfm) group and compare it to the "bigger" isobutyl that is present in pepstatin A. The results demonstrate that Tfm can effectively replace the isobutyl chain as far as inhibitory activity against plasmepsin II (PM II), an aspartic proteinase from Plasmodium falciparum, is concerned. On the other hand, replacement of isobutyl by Tfm selectively affected activity against other aspartic proteinases tested. Two lines of evidence led to these conclusions. Firstly, compounds 1 and 2 retained single-digit nanomolar inhibitory activity against PM II, but were markedly less active against PM IV, cathepsin D and cathepsin E. Secondly, the X-ray crystal structures of the three complexes of PM II with 1, 2 and pepstatin A were obtained at 2.8, 2.4 and 1.7 A resolution, respectively. High overall similarity among the three complexes indicated that the central Tfm was well accommodated in the lipophilic S1 pocket of PM II, where it was involved in tight hydrophobic contacts. The interaction of PM II with Phe111 appeared to be crucial. Comparison of the crystal structures presented here, with X-ray structures or structural models of PM IV and cathepsin D, allowed an interpretation of the inhibition profiles of pepstatin A and its Tfm variants against these three enzymes. Interactions of the P1 side chain with amino acids that point into the S1 pocket appear to be critical for inhibitory activity. In summary, Tfm can be used to replace an isobutyl group and can affect the selectivity profile of a compound. These findings have implications for the design of novel bioactive molecules and synthetic mimics of natural compounds.
Collapse
Affiliation(s)
- Christoph Binkert
- Actelion Pharmaceuticals Ltd. Gewerbestrasse 16, 4123 Allschwil, Switzerland.
| | | | | | | | | | | | | | | |
Collapse
|
156
|
Ersmark K, Nervall M, Gutiérrez-de-Terán H, Hamelink E, Janka LK, Clemente JC, Dunn BM, Gogoll A, Samuelsson B, Qvist J, Hallberg A. Macrocyclic inhibitors of the malarial aspartic proteases plasmepsin I, II, and IV. Bioorg Med Chem 2005; 14:2197-208. [PMID: 16307884 DOI: 10.1016/j.bmc.2005.11.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2005] [Accepted: 11/02/2005] [Indexed: 11/28/2022]
Abstract
The first macrocyclic inhibitor of the Plasmodium falciparum aspartic proteases plasmepsin I, II, and IV with considerable selectivity over the human aspartic protease cathepsin D has been identified. A series of macrocyclic compounds were designed and synthesized. Cyclizations were accomplished using ring-closing metathesis with the second generation Grubbs catalyst. These compounds contain either a 13-membered or a 16-membered macrocycle and incorporate a 1,2-dihydroxyethylene as transition state mimicking unit. The binding mode of this new class of compounds was predicted with automated docking and molecular dynamics simulations, with an estimation of the binding affinities through the linear interaction energy (LIE) method.
Collapse
Affiliation(s)
- Karolina Ersmark
- Department of Medicinal Chemistry, Uppsala University, BMC, PO Box 574, SE-751 23 Uppsala, Sweden
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
157
|
Ersmark K, Nervall M, Hamelink E, Janka LK, Clemente JC, Dunn BM, Blackman MJ, Samuelsson B, Aqvist J, Hallberg A. Synthesis of malarial plasmepsin inhibitors and prediction of binding modes by molecular dynamics simulations. J Med Chem 2005; 48:6090-106. [PMID: 16162010 DOI: 10.1021/jm050463l] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A series of inhibitors of the malarial aspartic proteases Plm I and II have been synthesized with L-mannitol as precursor. These inhibitors are characterized by either a diacylhydrazine or a five-membered oxadiazole ring replacing backbone amide functionalities. Molecular dynamics simulations were applied in the design process. The computationally predicted Plm II Ki values were generally in excellent agreement with the biological results. The diacylhydrazine was found to be superior over the oxadiazole as an amide bond replacement in the Plm I and II inhibitors studied. An extensive flexibility of the S2' pocket was captured by the simulations predicting the binding mode of the unsymmetrical inhibitors. Plm I and II inhibitors with single digit nanomolar Ki values devoid of inhibitory activity toward human Cat D were identified. One compound, lacking amide bonds, was found to be Plm IV selective and very potent, with a Ki value of 35 nM.
Collapse
Affiliation(s)
- Karolina Ersmark
- Department of Medicinal Chemistry, Uppsala University, BMC, Box 574, 751 23 Uppsala, Sweden
| | | | | | | | | | | | | | | | | | | |
Collapse
|
158
|
Bhargavi R, Sastry GM, Murty US, Sastry GN. Structural and active site analysis of plasmepsins of Plasmodium falciparum: Potential anti-malarial targets. Int J Biol Macromol 2005; 37:73-84. [PMID: 16242183 DOI: 10.1016/j.ijbiomac.2005.08.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2005] [Revised: 08/23/2005] [Accepted: 08/23/2005] [Indexed: 11/21/2022]
Abstract
Comparative protein modeling, active site analysis and binding site specificity for the homologous series of plasmepsins (PM's), present in food vacuole of Plasmodium falciparum, are carried out. Four loops (L1, L2, L3 and L4), which show maximum structural deviations irrespective of type of inhibitor, have been identified. Comparison of the crystal structures of ligand complexes reveal that residues belonging to these loops have negligible coulomb and VDW interactions with the inhibitor but play major role in determining the openness of the binding cavity. The coulomb and VDW interactions between the PMII subsite pockets and inhibitors, which play a major role in determining the inhibition constants, are delineated. Besides small displacements, the catalytic residues D32 of PMII undergoes rotation around the Cgamma-Cbeta single bond to assist catalysis whereas side chain conformational deviations are not observed in D214 on plasmepsin activation. The mutant S79D of PMII (and the corresponding residues of PMI and PMIV) which helps in recognizing and cleaving substrates containing lysine at P1 position is surrounded by highly polar atmosphere stabilized by lysine. However, in PMIII significantly lower polar atmosphere around the mutant A78S/A78D is observed. Large buried side chain area of residues located at M15 and I289 of PMII (and corresponding residues of PMI and PMIV) corroborates well with increase in specificity constant for hydrophobic substrates.
Collapse
Affiliation(s)
- Rayavarapu Bhargavi
- Biology Division, Indian Institute of Chemical Technology, Hyderabad 500007, India
| | | | | | | |
Collapse
|
159
|
Valbuena J, Vera R, Puentes A, Ocampo M, Garcia J, Curtidor H, Lopez R, Rodriguez L, Rosas J, Cortes J, Forero M, Pinto M, Patarroyo ME. P. falciparum pro-histoaspartic protease (proHAP) protein peptides bind specifically to erythrocytes and inhibit the invasion process in vitro. Biol Chem 2005; 386:361-7. [PMID: 15899698 DOI: 10.1515/bc.2005.043] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Plasmodium falciparum histoaspartic protease (HAP) is an active enzyme involved in haemoglobin degradation. HAP is expressed as an inactive 51-kDa zymogen and is cleaved into an active 37-kDa enzyme. It has been proposed that this kind of protease might be implicated in the parasite's invasion of erythrocytes; however, this protein's role during invasion has still to be determined. Synthetic peptides derived from the HAP precursor (proHAP) were tested in erythrocyte binding assays to identify their possible function in the invasion process. Two proHAP high-activity binding peptides (HABPs) specifically bound to erythrocytes; these peptides were numbered 30609 (101LKNYIKESVKLFNKGLTKKS120) and 30610 (121YLGSEFDNVELKDLANVLSF140 ). The binding of these two peptides was saturable, presenting nanomolar affinity constants. These peptides interacted with 26- and 45-kDa proteins on the erythrocyte surface; the nature of these receptor sites was studied in peptide binding assays using enzyme-treated erythrocytes. The HABPs showed greater than 90% merozoite invasion inhibition in in vitro assays. Goat serum containing proHAP polymeric peptide antibodies inhibited parasite invasion in vitro .
Collapse
Affiliation(s)
- John Valbuena
- Fundacion Instituto de Inmunologia de Colombia (FIDIC), Cra 50 26-00, Bogotá, Colombia.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
160
|
Menotti J, Santillana-Hayat M, Cassinat B, Sarfati C, Derouin F, Molina JM. Inhibitory activity of human immunodeficiency virus aspartyl protease inhibitors against Encephalitozoon intestinalis evaluated by cell culture-quantitative PCR assay. Antimicrob Agents Chemother 2005; 49:2362-6. [PMID: 15917534 PMCID: PMC1140512 DOI: 10.1128/aac.49.6.2362-2366.2005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Immune reconstitution might not be the only factor contributing to the low prevalence of microsporidiosis in human immunodeficiency virus (HIV)-infected patients treated with protease inhibitors, as these drugs may exert a direct inhibitory effect against fungi and protozoa. In this study, we developed a cell culture-quantitative PCR assay to quantify Encephalitozoon intestinalis growth in U-373-MG human glioblastoma cells and used this assay to evaluate the activities of six HIV aspartyl protease inhibitors against E. intestinalis. A real-time quantitative PCR assay targeted the E. intestinalis small-subunit rRNA gene. HIV aspartyl protease inhibitors were tested over serial concentrations ranging from 0.2 to 10 mg/liter, with albendazole used as a control. Ritonavir, lopinavir, and saquinavir were able to inhibit E. intestinalis growth, with 50% inhibitory concentrations of 1.5, 2.2, and 4.6 mg/liter, respectively, whereas amprenavir, indinavir, and nelfinavir had no inhibitory effect. Pepstatin A, a reference aspartyl protease inhibitor, could also inhibit E. intestinalis growth, suggesting that HIV protease inhibitors may act through the inhibition of an E. intestinalis-encoded aspartyl protease. These results showed that some HIV protease inhibitors can inhibit E. intestinalis growth at concentrations that are achievable in vivo and that the real-time quantitative PCR assay that we used is a valuable tool for the in vitro assessment of the activities of drugs against E. intestinalis.
Collapse
Affiliation(s)
- Jean Menotti
- Laboratoire de Parasitologie-Mycologie, Hôpital Saint Louis, 1 avenue Claude Vellefaux, 75475 Paris Cedex 10, France.
| | | | | | | | | | | |
Collapse
|
161
|
Sharma A, Eapen A, Subbarao SK. Purification and Characterization of a Hemoglobin Degrading Aspartic Protease from the Malarial Parasite Plasmodium vivax. ACTA ACUST UNITED AC 2005; 138:71-8. [PMID: 16046450 DOI: 10.1093/jb/mvi105] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Aspartic proteases of human malarial parasites are thought to play key roles in essential pathways of merozoite release, invasion and host cell hemoglobin degradation during the intraerythrocytic stages of their life cycle. Therefore, we have purified and characterized Plasmodium vivax aspartic protease, to determine if this enzyme can be used as potential drug target/immunogen, and its inhibitors as potential antimalarial drug. The P. vivax aspartic protease has been purified by a combination of ion exchange and size exclusion chromatographies and HPLC. Its properties were examined in order to define a role in the hemoglobin degradation process. The purified enzyme migrated as a single band on native PAGE and SDS/PAGE with a molecular mass of 40 kDa. Gelatin zymogram analyses revealed a clear zone of proteolytic activity corresponding to the band obtained on native PAGE and SDS/PAGE. The enzyme has an optimal pH of 4.0 and exhibits its highest activity at 37 degrees C. The enzyme is inhibited by pepstatin, but not by other inhibitors including o-phenanthroline, EDTA, PMSF or E-64, supporting its designation as an aspartic protease; its IC50 value was found to be 3.0 microM. A Lineweaver Burk double reciprocal plot with pepstatin shows that the inhibition is competitive with respect to the substrate. Ca2+ and Mg2+ ions enhance the protease activity, whereas Cu2+ and Hg2+ ions were found to be inhibitory. The pivotal role of aspartic protease in initiating hemoglobin degradation in P. vivax malaria parasite is also demonstrated.
Collapse
Affiliation(s)
- Arun Sharma
- Malaria Research Centre, 22 Sham Nath Marg, Delhi-110 054, India.
| | | | | |
Collapse
|
162
|
Abdel-Rahman HM, Kimura T, Hidaka K, Kiso A, Nezami A, Freire E, Hayashi Y, Kiso Y. Design of inhibitors against HIV, HTLV-I, and Plasmodium falciparum aspartic proteases. Biol Chem 2005; 385:1035-9. [PMID: 15576323 DOI: 10.1515/bc.2004.134] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Aspartic proteases have emerged as targets for substrate-based inhibitor design due to their vital roles in the life cycles of the organisms that cause AIDS, malaria, leukemia, and other infectious diseases. Based on the concept of mimicking the substrate transition-state, we designed and synthesized a novel class of aspartic protease inhibitors containing the hydroxymethylcarbonyl (HMC) isostere. An unnatural amino acid, allophenylnorstatine [Apns; (2 S ,3 S )-3-amino-2-hydroxy-4-phenylbutyric acid], was incorporated at the P1 site in a series of peptidomimetic compounds that mimic the natural substrates of the HIV, HTLV-I, and malarial aspartic proteases. From extensive structure-activity relationship studies, we were able to identify a series of highly potent peptidomimetic inhibitors of HIV protease. One highly potent inhibitor of the malarial aspartic protease (plasmepsin II) was identified. Finally, a promising lead compound against the HTLV-I protease was identified.
Collapse
Affiliation(s)
- Hamdy M Abdel-Rahman
- Department of Medicinal Chemistry, Center for Frontier Research in Medicinal Science, Kyoto Pharmaceutical University, Yamashina-ku, Kyoto 607-8412, Japan
| | | | | | | | | | | | | | | |
Collapse
|
163
|
Abstract
The life cycle of the malaria parasite contains three distinct invasive forms, or zoites. For at least two of these--the sporozoite and the blood-stage merozoite--invasion into their respective host cell requires the activity of parasite proteases. This review summarizes the evidence for this, discusses selected well-described proteolytic modifications linked to invasion, and describes recent progress towards identifying the proteases involved.
Collapse
Affiliation(s)
- Michael J Blackman
- Division of Parasitology, National Institute for Medical Research, Mill Hill, London NW7 1AA, UK.
| |
Collapse
|
164
|
Abstract
Plasmepsin II (PM II) is an aspartic protease active in hemoglobin (Hb) degradation in the protozoan parasite Plasmodium falciparum. A fluorescence-quenched octapeptide substrate based on the initial hemoglobin cleavage site is recognized well by PM II. C-terminal extension of this peptide has little effect, but N-terminal extension results in higher maximal velocity and dramatic concentration-dependent substrate inhibition. This inhibition, but not the rate stimulation, depends on the presence of a DABCYL group on the peptide N terminus. Using site-directed mutagenesis, we have identified PM II residues that interact with N-terminal amino acids of peptide substrates. The same residues influence degradation of Hb by PM II. Cathepsin E (CatE), a related mammalian aspartic protease, is also stimulated by N-terminally extended substrates. This suggests that distal substrate interactions as far out as P6 may be a general property of aspartic proteases and may be important in substrate and inhibitor recognition. Although PM II and CatE are similar in their ability to cleave Hb-based peptides and Hb alpha-chains, CatE is not able to degrade native Hb, which is a substrate for PM II. Based on these results, we propose that PM II may have the special feature of being a Hb denaturase.
Collapse
Affiliation(s)
- Eva S Istvan
- Department of Medicine, Howard Hughes Medical Institute, Washington University School of Medicine, St. Louis, Missouri 63110, USA
| | | |
Collapse
|
165
|
Liu J, Gluzman IY, Drew ME, Goldberg DE. The role of Plasmodium falciparum food vacuole plasmepsins. J Biol Chem 2004; 280:1432-7. [PMID: 15513918 DOI: 10.1074/jbc.m409740200] [Citation(s) in RCA: 140] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Plasmepsins (PMs) are thought to have an important function in hemoglobin degradation in the malarial parasite Plasmodium falciparum and have generated interest as antimalarial drug targets. Four paralogous plasmepsins reside in the food vacuole of P. falciparum. Targeted gene disruption by double crossover homologous recombination has been employed to study food vacuole plasmepsin function in cultured parasites. Parasite clones with deletions in each of the individual PM I, PM II, and HAP genes as well as clones with a double PM IV/PM I disruption have been generated. All of these clones lack the corresponding PMs, are viable, and appear morphologically normal. PM II and PM IV/I disruptions have longer doubling times than the 3D7 parental line in rich RPMI medium. This appears to be because of a decreased level of productive progeny rather than an increased cell cycle time. In amino acid-limited medium, all four knockouts exhibit slower growth than the parental strain. Compared with 3D7, knock-out clone sensitivity to aspartic and cysteine protease inhibitors is changed minimally. These results suggest substantial functional redundancy and have important implications for the design of antimalarial drugs. The slow growth phenotype may explain why P. falciparum has maintained four plasmepsin genes with overlapping functions.
Collapse
Affiliation(s)
- Jun Liu
- Departments of Medicine and Molecular Microbiology, Howard Hughes Medical Institute, Washington University School of Medicine, St. Louis, Missouri 63110, USA
| | | | | | | |
Collapse
|
166
|
Dowse T, Soldati D. Host cell invasion by the apicomplexans: the significance of microneme protein proteolysis. Curr Opin Microbiol 2004; 7:388-96. [PMID: 15358257 DOI: 10.1016/j.mib.2004.06.013] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Intracellular life-style has been adopted by many pathogens as a successful immune evasion mechanism. To gain entry to a large variety of host cells and to establish an intracellular niche, Toxoplasma gondii and other apicomplexans rely on an active process distinct from phagocytosis. Calcium-regulated secretion of microneme proteins and parasite actin polymerization together with the action of at least one myosin motor act in concert to generate the gliding motility necessary to propel the parasite into host cells. During this active penetration, host cell transmembrane proteins are excluded from the forming parasitophorous vacuole hence conferring the resistance to acidification and degradative fusion. Apicomplexans possess a large repertoire of microneme proteins that contribute to invasion, but their precise role and the level of functional redundancy remain to be evaluated. Remarkably, most microneme proteins are proteolytically cleaved during biogenesis and post-exocytosis. The significance of the processing events and the identification of the proteases implicated are the object of intensive investigations. These proteases may constitute potential drug targets for intervention against malaria and other diseases caused by these parasites.
Collapse
Affiliation(s)
- Timothy Dowse
- Department of Biological Sciences, Imperial College London, Sir Alexander Fleming Building, South Kensington Campus, London SW7 2AZ, UK
| | | |
Collapse
|
167
|
Omara-Opyene AL, Moura PA, Sulsona CR, Bonilla JA, Yowell CA, Fujioka H, Fidock DA, Dame JB. Genetic disruption of the Plasmodium falciparum digestive vacuole plasmepsins demonstrates their functional redundancy. J Biol Chem 2004; 279:54088-96. [PMID: 15491999 DOI: 10.1074/jbc.m409605200] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The digestive vacuole plasmepsins PfPM1, PfPM2, PfPM4, and PfHAP (a histoaspartic proteinase) are 4 aspartic proteinases among 10 encoded in the Plasmodium falciparum malarial genome. These have been hypothesized to initiate and contribute significantly to hemoglobin degradation, a catabolic function essential to the survival of this intraerythrocytic parasite. Because of their perceived significance, these plasmepsins have been proposed as potential targets for antimalarial drug development. To test their essentiality, knockout constructs were prepared for each corresponding gene such that homologous recombination would result in two partial, nonfunctional gene copies. Disruption of each gene was achieved, as confirmed by PCR, Southern, and Northern blot analyses. Western and two-dimensional gel analyses revealed the absence of mature or even truncated plasmepsins corresponding to the disrupted gene. Reduced growth rates were observed with PfPM1 and PfPM4 knockouts, indicating that although these plasmepsins are not essential, they are important for parasite development. Abnormal mitochondrial morphology also appeared to accompany loss of PfPM2, and an abundant accumulation of electron-dense vesicles in the digestive vacuole was observed upon disruption of PfPM4; however, those phenotypes only manifested in about a third of the disrupted cells. The ability to compensate for loss of individual plasmepsin function may be explained by close similarity in the structure and active site of these four vacuolar enzymes. Our data imply that drug discovery efforts focused on vacuolar plasmepsins must incorporate measures to develop compounds that can inhibit two or more of this enzyme family.
Collapse
Affiliation(s)
- A Levi Omara-Opyene
- Department of Pathobiology, University of Florida, Gainesville, Florida 32611-0880, USA
| | | | | | | | | | | | | | | |
Collapse
|
168
|
Hoppe HC, van Schalkwyk DA, Wiehart UIM, Meredith SA, Egan J, Weber BW. Antimalarial quinolines and artemisinin inhibit endocytosis in Plasmodium falciparum. Antimicrob Agents Chemother 2004; 48:2370-8. [PMID: 15215083 PMCID: PMC434207 DOI: 10.1128/aac.48.7.2370-2378.2004] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Endocytosis is a fundamental process of eukaryotic cells and fulfills numerous functions, most notably, that of macromolecular nutrient uptake. Malaria parasites invade red blood cells and during their intracellular development endocytose large amounts of host cytoplasm for digestion in a specialized lysosomal compartment, the food vacuole. In the present study we have examined the effects of artemisinin and the quinoline drugs chloroquine and mefloquine on endocytosis in Plasmodium falciparum. By using novel assays we found that mefloquine and artemisinin inhibit endocytosis of macromolecular tracers by up to 85%, while the latter drug also leads to an accumulation of undigested hemoglobin in the parasite. During 5-h incubations, chloroquine inhibited hemoglobin digestion but had no other significant effect on the endocytic pathway of the parasite, as assessed by electron microscopy, the immunofluorescence localization of hemoglobin, and the distribution of fluorescent and biotinylated dextran tracers. By contrast, when chloroquine was added to late ring stage parasites, followed by a 12-h incubation, macromolecule endocytosis was inhibited by more than 40%. Moreover, there is an accumulation of transport vesicles in the parasite cytosol, possibly due to a disruption in vacuole-vesicle fusion. This fusion block is not observed with mefloquine, artemisinin, quinine, or primaquine but is mimicked by the vacuole alkalinizing agents ammonium chloride and monensin. These results are discussed in the light of present theories regarding the mechanisms of action of the antimalarials and highlight the potential use of drugs in manipulating and studying the endocytic pathway of malaria parasites.
Collapse
Affiliation(s)
- Heinrich C Hoppe
- Division of Pharmacology, University of Cape Town Medical School, Groote Schuur Hospital Old Building, Observatory, Cape Town 7925, South Africa.
| | | | | | | | | | | |
Collapse
|
169
|
Klemba M, Beatty W, Gluzman I, Goldberg DE. Trafficking of plasmepsin II to the food vacuole of the malaria parasite Plasmodium falciparum. ACTA ACUST UNITED AC 2004; 164:47-56. [PMID: 14709539 PMCID: PMC2171955 DOI: 10.1083/jcb200307147] [Citation(s) in RCA: 110] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A family of aspartic proteases, the plasmepsins (PMs), plays a key role in the degradation of hemoglobin in the Plasmodium falciparum food vacuole. To study the trafficking of proPM II, we have modified the chromosomal PM II gene in P. falciparum to encode a proPM II-GFP chimera. By taking advantage of green fluorescent protein fluorescence in live parasites, the ultrastructural resolution of immunoelectron microscopy, and inhibitors of trafficking and PM maturation, we have investigated the biosynthetic path leading to mature PM II in the food vacuole. Our data support a model whereby proPM II is transported through the secretory system to cytostomal vacuoles and then is carried along with its substrate hemoglobin to the food vacuole where it is proteolytically processed to mature PM II.
Collapse
Affiliation(s)
- Michael Klemba
- Department of Molecular Microbiology, Washington University School of Medicine, 660 S. Euclid Ave., Box 8230, St. Louis, MO 63110, USA
| | | | | | | |
Collapse
|
170
|
Moritz E, Seidensticker S, Gottwald A, Maier W, Hoerauf A, Njuguna JT, Kaiser A. The efficacy of inhibitors involved in spermidine metabolism in Plasmodium falciparum, Anopheles stephensi and Trypanosoma evansi. Parasitol Res 2004; 94:37-48. [PMID: 15278440 DOI: 10.1007/s00436-004-1162-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2004] [Accepted: 06/17/2004] [Indexed: 11/25/2022]
Abstract
In the present study, we have tested the effect of different polyamine inhibitors of the spermidine metabolizing enzymes deoxyhypusine synthase and homospermidine synthase in different chloroquine resistant Plasmodium falciparum strains, in the mosquito Anopheles stephensi (Diptera: Culicidae) and in a Trypanosoma evansi clone I from strain STIB 806 K China. Recent experiments have shown that agmatine is a growth inhibitor of the malaria parasite P. falciparum (Kaiser et al. 2001) in vitro. A comparison of agmatine efficacy with the new antimalarials artemisinin, triclosan and conventional chloroquine showed similar or even better results on the basis of growth inhibition and the reduction of developmental forms. However, no effect of triclosan or agmatine was observed at the ribonucleic acid level. In a second set of experiments, we tested the effect of 1,7-diaminoheptane and agmatine on oocyst formation in A. stephensi after infection with Plasmodium yoelii. Agmatine had an antisporozoite effect since 1,000 microM led to a 59.5% inhibition of oocysts. A much weaker inhibitor of oocyst formation was 1,7-diaminoheptane. The most effective in in vitro inhibition of T. evansi was dicyclohexylamine, an inhibitor of spermidine biosynthesis with an IC(50 ) value of 47.44 microM and the deoxyhypusine inhibitor 1,7-diaminoheptane with an IC(50) value of 47.80 microM. However, both drugs were ineffective in in vivo experiments in a Trypanosoma mouse model. Two different spermidine analogues, 1,8-diaminooctane and 1,3-diaminopropane with IC(50) values of 171 microM and 181.37 microM, respectively, were moderate inhibitors in vitro and ineffective in vivo.
Collapse
Affiliation(s)
- E Moritz
- Institut für Medizinische Parasitologie, Sigmund Freud Strasse 25, 53105 Bonn, Germany
| | | | | | | | | | | | | |
Collapse
|
171
|
Na BK, Lee EG, Lee HW, Cho SH, Bae YA, Kong Y, Lee JK, Kim TS. Aspartic proteases of Plasmodium vivax are highly conserved in wild isolates. THE KOREAN JOURNAL OF PARASITOLOGY 2004; 42:61-6. [PMID: 15181345 PMCID: PMC2717343 DOI: 10.3347/kjp.2004.42.2.61] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The plasmepsins are the aspartic proteases of malaria parasites. Treatment of aspartic protease inhibitor inhibits hemoglobin hydrolysis and blocks the parasite development in vitro suggesting that these proteases might be exploited their potentials as antimalarial drug targets. In this study, we determined the genetic variations of the aspartic proteases of Plasmodium vivax (PvPMs) of wild isolates. Two plasmepsins (PvPM4 and PvPM5) were cloned and sequenced from 20 P. vivax Korean isolates and two imported isolates. The sequences of the enzymes were highly conserved except a small number of amino acid substitutions did not modify key residues for the function or the structure of the enzymes. The high sequence conservations between the plasmepsins from the isolates support the notion that the enzymes could be reliable targets for new antimalarial chemotherapeutics.
Collapse
Affiliation(s)
- Byoung-Kuk Na
- Department of Molecular Parasitology and Center for Molecular Medicine, Sungkyunkwan University School of Medicine and Samsung Biomedical Research Institute, Suwon 440-746, Korea.
| | | | | | | | | | | | | | | |
Collapse
|
172
|
Johansson PO, Chen Y, Belfrage AK, Blackman MJ, Kvarnström I, Jansson K, Vrang L, Hamelink E, Hallberg A, Rosenquist A, Samuelsson B. Design and synthesis of potent inhibitors of the malaria aspartyl proteases plasmepsin I and II. Use of solid-phase synthesis to explore novel statine motifs. J Med Chem 2004; 47:3353-66. [PMID: 15189032 DOI: 10.1021/jm031106i] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Picomolar to low nanomolar inhibitors of the two aspartic proteases plasmepsin (Plm) I and II, from the malaria parasite Plasmodium falciparum, have been identified from sets of libraries containing novel statine-like templates modified at the amino and carboxy terminus. The syntheses of the novel statine templates were carried out in solution phase using efficient synthetic routes and resulting in excellent stereochemical control. The most promising statine template was attached to solid support and diversified by use of parallel synthesis. The products were evaluated for their Plm I and II inhibitory activity as well as their selectivity over cathepsin D. Selected inhibitors were, in addition, evaluated for their inhibition of parasite growth in cultured infected human red blood cells. The most potent inhibitor in this report, compound 16, displays Ki values of 0.5 and 2.2 nM for Plm I and II, respectively. Inhibitor 16 is also effective in attenuating parasite growth in red blood cells showing 51% inhibition at a concentration of 5 microM. Several inhibitors have been identified that exhibit Ki values between 0.5 and 74 nM for both Plm I and II. Some of these inhibitors also show excellent selectivity vs cathepsin D.
Collapse
Affiliation(s)
- Per-Ola Johansson
- Department of Chemistry, Linköping University, S-581 83 Linköping, Sweden
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
173
|
Abstract
Proteases play critical roles in the life cycle of the malaria parasite, Plasmodium spp. Within the asexual erythrocytic cycle, responsible for the clinical manifestations of malaria, substantial interest has focused on the role of parasite serine proteases as a result of indications that they are involved in red blood cell invasion. Over the past 6 years, three Plasmodium genes encoding serine proteases of the subtilisin-like clan, or subtilases, have been identified. All are expressed in the asexual blood stages and, in at least two cases, the gene products localize to secretory organelles of the invasive merozoite. They may have potential as novel drug targets. Here, we review progress in our understanding of the maturation, specificity, structure and function of these Plasmodium subtilases.
Collapse
|
174
|
Caffrey CR, McKerrow JH, Salter JP, Sajid M. Blood ‘n’ guts: an update on schistosome digestive peptidases. Trends Parasitol 2004; 20:241-8. [PMID: 15105025 DOI: 10.1016/j.pt.2004.03.004] [Citation(s) in RCA: 120] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Conor R Caffrey
- Sandler Center for Basic Research in Parasitic Diseases, Box 0511, University of California-San Francisco, San Francisco, CA 94143, USA.
| | | | | | | |
Collapse
|
175
|
Fontaine F, Pastor M, Sanz F. Incorporating Molecular Shape into the Alignment-free GRid-INdependent Descriptors. J Med Chem 2004; 47:2805-15. [PMID: 15139758 DOI: 10.1021/jm0311240] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The recently introduced GRid-INdependent Descriptors (GRIND) were designed to provide a suitable description of a series of ligands for 3D-QSAR studies not requiring the spatial superimposition of their structures. Despite the proven usefulness of the method, it was recognized that the original GRIND failed to describe appropriately the shape of the ligand molecules, which in some cases plays a major role in ligand-receptor binding. For this reason, the original descriptors have been enhanced with the addition of a molecular shape description based on the local curvature of the molecular surface. The integration of this description into the GRIND allows the generation of 3D-QSAR models able to identify both favorable and unfavorable shape complementarity in a simple and alignment-independent way. The usefulness of the new GRIND-shape description in 3D-QSAR is illustrated using two structure-activity studies: one performed on a set of xanthine-like antagonists of the A(1) adenosine receptor; another performed on a series of Plasmodium falciparum plasmepsin II inhibitors.
Collapse
Affiliation(s)
- Fabien Fontaine
- Research Unit on Biomedical Informatics (GRIB), IMIM, Universitat Pompeu Fabra, C/Dr. Aiguader, 80, E-08003 Barcelona, Spain
| | | | | |
Collapse
|
176
|
Tossi A, Benedetti F, Norbedo S, Skrbec D, Berti F, Romeo D. Small hydroxyethylene-based peptidomimetics inhibiting both HIV-1 and C. albicans aspartic proteases. Bioorg Med Chem 2004; 11:4719-27. [PMID: 14556787 DOI: 10.1016/j.bmc.2003.08.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We have extended a highly flexible method for rapidly assembling aspartic protease inhibitors to produce symmetric and asymmetric monohydroxyethylene peptidomimetics. This method is based on the prior synthesis of the central non-cleavable peptide-bond isostere [NH(2)-P(1)psiP1'-NH(2); psi=hydroxyethylene isostere, HNCH(Bz)CHOHCH(2)CH(Bz)NH], with the possibility of accurately controlling its stereochemistry (S,S,S or S,R,S), and subsequently adding appropriate flanking units, chosen from commercially available amino acids, aromatic carboxylic acids, or phenoxyacetic acid (Poa) derivatives. The method was used to make asymmetric inhibitors of general formula Kyn-Xaa-PhepsiPhe-dmPoa, (Kyn=kynurenic acid, Xaa=Val, Thr or D-thienylglycine, M(r)=716-754) and symmetric inhibitors of formula xPoa-PhepsiPhe-xPoa (xPoa=Poa or dimethyl-, hydroxy-, formyl- or acetyl-Poa, M(r)=553-609), with logP(o/w) values ranging from 4.1 to 7.6. Inhibition of HIV-PR did not depend on the stereochemistry of the hydroxyl group, while it depended markedly on the substituents present on the Poa residues, with dmPoa being preferred over Poa or its more hydrophilic derivatives. Conversely, inhibition of Candida albicans Sap2 was higher for the S,S,S epimers, and Poa or its hydrophilic derivatives were preferred over dmPoa.
Collapse
Affiliation(s)
- Alessandro Tossi
- Department of Biochemistry, Biophysics and Macromolecular Chemistry, University of Trieste, Via Giorgieri 1, I-34127 Trieste, Italy.
| | | | | | | | | | | |
Collapse
|
177
|
Salas E, Ramírez A, Otero-Bilbao A, Vázquez R, Reyes O, Mendiola J, Duarte CA, Otero-González A, Gutiérrez OA, Chávez MA. A heterogeneous enzymatic assay for quantification of Plasmepsin II activity and the evaluation of its inhibitors. J Pharm Biomed Anal 2004; 34:833-40. [PMID: 15019062 DOI: 10.1016/s0731-7085(03)00566-1] [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] [Accepted: 09/14/2003] [Indexed: 10/26/2022]
Abstract
The emergence and worldwide spreading of Plasmodium falciparum strains that shown to be resistant to traditional drugs is considered a very serious health problem, given the high mortality and morbidity rate of Malaria. In the search for new drugs against this parasite, Hb hydrolyzing enzymes, such as Plasmepsin II (Plm II), have been classified as very promising targets for therapeutic attacks. In this work, it is developed a cheap and high-throughput heterogeneous enzymatic assay for measuring Plasmepsin II activity in order to use it as a tool in the discovery of new inhibitors of this enzyme. In this assay, Plasmepsin II acts upon a solid-phase bound synthetic peptide (DU2) whose sequence comprises the cleavage site F(33)-L(34) present in Hb alpha-chain. The peptide surface density is quantified by means of a classical ELISA-based procedure. In order to estimate the kinetic constants of the system and to quantify both, enzymatic and inhibitory activity, it was used a model for the kinetics of enzyme quasi-saturable systems previously developed by our group, that fitted very well to the experimental data. It was used Pepstatin as a model inhibitor of Plasmepsin II and the resulting dose-response relation agreed with the expected behavior for the Pepstatin-Plasmepsin II pair under the employed experimental conditions.
Collapse
Affiliation(s)
- Emir Salas
- Centro de Estudio de Proteínas, Facultad de Biología, Universidad de la Habana, Calle 25 # 455 Entre J e I, Vedado, CP 10400, Havana City, Cuba.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
178
|
Tripathi AK, Khan SI, Walker LA, Tekwani BL. Spectrophotometric determination of de novo hemozoin/β-hematin formation in an in vitro assay. Anal Biochem 2004; 325:85-91. [PMID: 14715288 DOI: 10.1016/j.ab.2003.10.016] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Formation of hemozoin in the malaria parasite, due to its unique nature, is an attractive molecular target. Several laboratories have been trying to unravel the molecular mechanism of hemozoin biosynthesis within the parasite digestive vacuoles. Use of different assay protocols for in vitro beta-hematin (synthetic identical to hemozoin) formation by these laboratories has led to inconsistent and often contradictory findings. Much of the difficulty may be attributed to oligomeric heme aggregates, which may be indistinguishable in some detection approaches if adequate separation of beta-hemtin is not achieved. Therefore, there is an urgent need for a widely accepted protocol for in vitro beta-hematin formation. We describe here a spectrophotometric assay for in vitro beta-hematin formation. The assay has been validated with the Plasmodium falciparum lysate, the parasite lipid extracts, and some commercially available fatty acids, which are known to initiate/catalyze beta-hematin formation in vitro. The necessity for multiple wash steps for accurate quantification of de novo hemozoin/beta-hematin formation was verified experimentally. It was necessary to wash the pellet, which contains beta-hematin and heme aggregates, sequentially with Tris/SDS buffer and alkaline bicarbonate solution for complete removal of monomeric heme and heme aggregates and accurate quantification of beta-hematin formed during the assay. The pellets and side products in the supernatant were characterized by infrared spectroscopy. No beta-hematin formation occurred in the absence of a catalytic/initiating factor. Based on these findings, a filtration-based assay that uses 96-well microplates, and which has important application in in vitro screening and identification of novel inhibitors of hemozoin formation as potential blood schizontocidal antimalarials, has been developed.
Collapse
Affiliation(s)
- Abhai K Tripathi
- National Center for Natural Products Research, Research Institute of Pharmaceutical Sciences, School of Pharmacy, University of Mississippi, MS 38677, USA
| | | | | | | |
Collapse
|
179
|
Kiso A, Hidaka K, Kimura T, Hayashi Y, Nezami A, Freire E, Kiso Y. Search for substrate-based inhibitors fitting the S2? space of malarial aspartic protease plasmepsin II. J Pept Sci 2004; 10:641-7. [PMID: 15568678 DOI: 10.1002/psc.609] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Plasmepsin (Plm) has been identified as an important target for the development of new antimalarial drugs, since its inhibition leads to the starvation of Plasmodium falciparum. A series of substrate-based dipeptide-type Plm II inhibitors containing the hydroxymethylcarbonyl isostere as a transition-state mimic were synthesized. The general design principle was provision of a conformationally restrained hydroxyl group (corresponding to the set residue at the P2' position in native substrates) and a bulky unit to fit the S2' pocket.
Collapse
Affiliation(s)
- Aiko Kiso
- Department of Medicinal Chemistry, Center for Frontier Research in Medicinal Science, Kyoto Pharmaceutical University, Yamashina-ku, Kyoto 607-8412, Japan.
| | | | | | | | | | | | | |
Collapse
|
180
|
Buss AD, Butler MS. A new model for utilising chemical diversity from natural sources. Drug Dev Res 2004. [DOI: 10.1002/ddr.10389] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
181
|
Uzureau P, Barale JC, Janse CJ, Waters AP, Breton CB. Gene targeting demonstrates that thePlasmodium bergheisubtilisin PbSUB2 is essential for red cell invasion and reveals spontaneous genetic recombination events. Cell Microbiol 2004; 6:65-78. [PMID: 14678331 DOI: 10.1046/j.1462-5822.2003.00343.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The Plasmodium merozoite proteases involved in the crucial process of erythrocyte invasion are promising targets for novel malaria control strategies. We report here the characterization of the subtilisin-like protease SUB2 from the rodent parasites Plasmodium berghei and Plasmodium yoelii, leading the way to in vivo functional studies of this enzyme. The kinetics of expression and subcellular localization imply a central role for SUB2 in erythrocyte invasion. Through the use of gene targeting strategies, we assessed the relevance of P. berghei SUB2 for the intraerythrocytic cycle. The selection of recombinant Pbsub2-TrimycDuoXpress-tagged parasites and the proper expression of the modified coding region demonstrate that the Pbsub2 locus is accessible to genetic modifications. However, Pbsub2 knock-out parasites were not recovered, confirming the importance of PbSUB2 for P. berghei merozoite stages, and supporting the fact that its Plasmodium falciparum SUB2 orthologue is an attractive drug target candidate. Finally, we identify revertant parasites that have lost the integrated selection cassette while conserving a Pbsub2-tagged gene. These spontaneous reversion events should overcome the scarcity of selectable markers available for this parasite, giving access to multiple gene tagging strategies, which, together with the validation of a TrimycDuoXpress tag, would represent valuable new tools for studying the biology of P. berghei.
Collapse
Affiliation(s)
- Pierrick Uzureau
- Unité de Biologie des Interactions Hôte-Parasite, Institut Pasteur/CNRS URA 2581, 25 Rue du Dr Roux, 75015 Paris, France
| | | | | | | | | |
Collapse
|
182
|
Selmeczi K, Robert A, Claparols C, Meunier B. Alkylation of human hemoglobin A0by the antimalarial drug artemisinin. FEBS Lett 2003; 556:245-8. [PMID: 14706857 DOI: 10.1016/s0014-5793(03)01448-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
In vitro, the heme cofactor of human iron(II) hemoglobin was efficiently and quickly alkylated at meso positions by the peroxide-based antimalarial drug artemisinin, leading to heme-artemisinin-derived covalent adducts. This reaction occurred in the absence of any added protease or in the presence of an excess of an extra non-heme protein, or even when artemisinin was added to hemolysed human blood. This activation of artemisinin by the heme moiety of non-digested hemoglobin clearly indicates the high affinity of this drug for heme, and its efficient alkylating ability under very mild conditions.
Collapse
Affiliation(s)
- Katalin Selmeczi
- Laboratoire de Chimie de Coordination du CNRS, 205 route de Narbonne, 31077 Cedex 4, Toulouse, France
| | | | | | | |
Collapse
|
183
|
Ersmark K, Feierberg I, Bjelic S, Hamelink E, Hackett F, Blackman MJ, Hultén J, Samuelsson B, Aqvist J, Hallberg A. Potent Inhibitors of the Plasmodium falciparum Enzymes Plasmepsin I and II Devoid of Cathepsin D Inhibitory Activity. J Med Chem 2003; 47:110-22. [PMID: 14695825 DOI: 10.1021/jm030933g] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The hemoglobin-degrading aspartic proteases plasmepsin I (Plm I) and plasmepsin II (Plm II) of the malaria parasite Plasmodium falciparum have lately emerged as putative drug targets. A series of C(2)-symmetric compounds encompassing the 1,2-dihydroxyethylene scaffold and a variety of elongated P1/P1' side chains were synthesized via microwave-assisted palladium-catalyzed coupling reactions. Binding affinity calculations with the linear interaction energy method and molecular dynamics simulations reproduced the experimental binding data obtained in a Plm II assay with very good accuracy. Bioactive conformations of the elongated P1/P1' chains were predicted and agreed essentially with a recent X-ray structure. The compounds exhibited picomolar to nanomolar inhibition constants for the plasmepsins and no measurable affinity to the human enzyme cathepsin D. Some of the compounds also demonstrated significant inhibition of parasite growth in cell culture. To the best of our knowledge, these plasmepsin inhibitors represent the most selective reported to date and constitute promising lead compounds for further optimization.
Collapse
Affiliation(s)
- Karolina Ersmark
- Department of Medicinal Chemistry, Uppsala University, BMC, Box 574, SE-751 23 Uppsala, Sweden
| | | | | | | | | | | | | | | | | | | |
Collapse
|
184
|
Pattanaik P, Jain B, Ravindra G, Gopi HN, Pal PP, Balaram H, Balaram P. Stage-specific profiling of Plasmodium falciparum proteases using an internally quenched multispecificity protease substrate. Biochem Biophys Res Commun 2003; 309:974-9. [PMID: 13679069 DOI: 10.1016/j.bbrc.2003.08.108] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Novel internally quenched fluorescence peptide substrates containing sequence specific sites for cleavage by multiple proteases were designed and synthesized. The 28 and 29 residue peptides contain an N-terminal fluorescence acceptor group, 4-(4-dimethylaminophenylazo)benzoic acid (DABCYL), and a C-terminal fluorescence donor group, 5-(2-aminoethylamino)naphthalene-1-sulfonic acid (EDANS). Efficient energy transfer between the donor and acceptor groups flanking the peptide sequence was achieved by incorporation of a central DPro-Gly segment, which serves as a conformation nucleating site, inducing hairpin formation. This multispecificity protease substrate was used to profile the proteolytic activities in the malarial parasite Plasmodium falciparum in a stage dependent manner using a combination of fluorescence and MALDI mass spectrometry. Cysteine protease activity was shown to be dominating at neutral pH, whereas aspartic protease activity contributed predominantly to the proteolytic repertoire at acidic pH. Maximum proteolysis was observed at the trophozoite stage followed by the schizonts and the rings.
Collapse
Affiliation(s)
- Priyaranjan Pattanaik
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India
| | | | | | | | | | | | | |
Collapse
|
185
|
Martins TM, Novo C, do Rosário VE, Domingos A. Aspartic proteases from Plasmodium chabaudi: a rodent model for human malaria. Acta Trop 2003; 89:1-12. [PMID: 14636976 DOI: 10.1016/s0001-706x(03)00199-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Intraerythrocytic malaria parasites degrade haemoglobin to provide nutrients for their own growth and maturation. Plasmodium aspartic proteases known as plasmepsins play an important role on haemoglobin degradation and are being studied as drug targets for chemotherapy of malaria. The rodent model for human malaria, Plasmodium chabaudi, is an experimentally good model for therapy drug design. The gene encoding an aspartic protease precursor (proplasmepsin) from the rodent malaria parasite P. chabaudi was cloned and sequenced. A theoretical 3D structure model was constructed by comparative homology and used for superimposition with other known models. Analysis of the P. chabaudi and Plasmodium yoelli genomes revealed in both the presence of at least seven plasmepsins and each one has sequence similarity to its plasmepsin counterpart of the human malaria Plasmodium falciparum. The predicted proteins were confirmed as plasmepsins by detection on Blocks Database of three characteristic blocks of the eukaryotic and viral aspartic protease family. Analysis of the proline-rich loop amino acid sequence of these plasmepsins suggests that they constitute characteristic motifs of each plasmepsin group suggesting that these sequence variations are related with different substrate specificities.
Collapse
Affiliation(s)
- Tiago M Martins
- Departamento de Biotecnologia, Instituto Nacional de Engenharia e Tecnologia Industrial, UTPAM, Edifício F, Estrada do Paço do Lumiar, 1649-038 Lisboa, Portugal
| | | | | | | |
Collapse
|
186
|
Bozdech Z, Llinás M, Pulliam BL, Wong ED, Zhu J, DeRisi JL. The transcriptome of the intraerythrocytic developmental cycle of Plasmodium falciparum. PLoS Biol 2003; 1:E5. [PMID: 12929205 PMCID: PMC176545 DOI: 10.1371/journal.pbio.0000005] [Citation(s) in RCA: 1164] [Impact Index Per Article: 55.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2003] [Accepted: 07/25/2003] [Indexed: 01/27/2023] Open
Abstract
Plasmodium falciparum is the causative agent of the most burdensome form of human malaria, affecting 200-300 million individuals per year worldwide. The recently sequenced genome of P. falciparum revealed over 5,400 genes, of which 60% encode proteins of unknown function. Insights into the biochemical function and regulation of these genes will provide the foundation for future drug and vaccine development efforts toward eradication of this disease. By analyzing the complete asexual intraerythrocytic developmental cycle (IDC) transcriptome of the HB3 strain of P. falciparum, we demonstrate that at least 60% of the genome is transcriptionally active during this stage. Our data demonstrate that this parasite has evolved an extremely specialized mode of transcriptional regulation that produces a continuous cascade of gene expression, beginning with genes corresponding to general cellular processes, such as protein synthesis, and ending with Plasmodium-specific functionalities, such as genes involved in erythrocyte invasion. The data reveal that genes contiguous along the chromosomes are rarely coregulated, while transcription from the plastid genome is highly coregulated and likely polycistronic. Comparative genomic hybridization between HB3 and the reference genome strain (3D7) was used to distinguish between genes not expressed during the IDC and genes not detected because of possible sequence variations. Genomic differences between these strains were found almost exclusively in the highly antigenic subtelomeric regions of chromosomes. The simple cascade of gene regulation that directs the asexual development of P. falciparum is unprecedented in eukaryotic biology. The transcriptome of the IDC resembles a "just-in-time" manufacturing process whereby induction of any given gene occurs once per cycle and only at a time when it is required. These data provide to our knowledge the first comprehensive view of the timing of transcription throughout the intraerythrocytic development of P. falciparum and provide a resource for the identification of new chemotherapeutic and vaccine candidates.
Collapse
Affiliation(s)
- Zbynek Bozdech
- 1Department of Biochemistry and Biophysics, University of California, San FranciscoSan Francisco, CaliforniaUnited States of America
| | - Manuel Llinás
- 1Department of Biochemistry and Biophysics, University of California, San FranciscoSan Francisco, CaliforniaUnited States of America
| | - Brian Lee Pulliam
- 1Department of Biochemistry and Biophysics, University of California, San FranciscoSan Francisco, CaliforniaUnited States of America
| | - Edith D Wong
- 1Department of Biochemistry and Biophysics, University of California, San FranciscoSan Francisco, CaliforniaUnited States of America
| | - Jingchun Zhu
- 2Department of Biological and Medical Informatics, University of California, San FranciscoSan Francisco, CaliforniaUnited States of America
| | - Joseph L DeRisi
- 1Department of Biochemistry and Biophysics, University of California, San FranciscoSan Francisco, CaliforniaUnited States of America
| |
Collapse
|
187
|
Padmanaban G. Drug targets in malaria parasites. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2003; 84:123-41. [PMID: 12934935 DOI: 10.1007/3-540-36488-9_4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
Malaria ranks with tuberculosis and AIDS in terms of its ability to destroy human health. In India there are at least two million cases seen annually. Although mortality may not be as high as it is in Africa, the trauma due to morbidity and debility and loss of productive man hours are colossal. Since resistance to chloroquine and antifolates is spreading rapidly, there is need to develop new pharmacophores, for which identification of new drug targets is essential. This review focuses on targets arising from classical and unique metabolic pathways in the malaria parasite, highlighting the research being carried out in India in the context of the global scenario. A significant amount of research in India and elsewhere has provided new knowledge on parasite biology, that could pave the way for the development of new pharmacophores. However, it is a matter of regret to record that malaria being a poor man's disease does not enthuse pharmaceutical companies in general to invest and bring out new molecules. Developing countries like India should take a lead in developing new but affordable antimalarials.
Collapse
Affiliation(s)
- G Padmanaban
- Department of Biochemistry, Indian Institute of Science, Bangalore 560 012, India.
| |
Collapse
|
188
|
Williamson AL, Brindley PJ, Knox DP, Hotez PJ, Loukas A. Digestive proteases of blood-feeding nematodes. Trends Parasitol 2003; 19:417-23. [PMID: 12957519 DOI: 10.1016/s1471-4922(03)00189-2] [Citation(s) in RCA: 145] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Blood-feeding parasites employ a battery of proteolytic enzymes to digest the contents of their bloodmeal. Host haemoglobin is a major substrate for these proteases and, therefore, a driving force in the evolution of parasite-derived proteolytic enzymes. This review will focus on the digestive proteases of the major blood-feeding nematodes - hookworms (Ancylostoma spp. and Necator americanus) and the ruminant parasite, Haemonchus contortus - but also compares and contrasts these proteases with recent findings from schistosomes and malaria parasites. Haematophagous nematodes express proteases of different mechanistic classes in their intestines, many of which have proven or putative roles in degradation of haemoglobin and other proteins involved in nutrition. Moreover, the fine specificity of the relationships between digestive proteases and their substrate proteins provides a new molecular paradigm for understanding host-parasite co-evolution. Numerous laboratories are actively investigating these molecules as antiparasite vaccine targets.
Collapse
Affiliation(s)
- Angela L Williamson
- Department of Microbiology and Tropical Medicine, George Washington University Medical Center, Washington DC 20037, USA
| | | | | | | | | |
Collapse
|
189
|
Barry AE, Leliwa A, Choi M, Nielsen KM, Hartl DL, Day KP. DNA sequence artifacts and the estimation of time to the most recent common ancestor (TMRCA) of Plasmodium falciparum. Mol Biochem Parasitol 2003; 130:143-7. [PMID: 12946852 DOI: 10.1016/s0166-6851(03)00164-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Alyssa E Barry
- The Peter Medawar Building for Pathogen Research and Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3SY, UK.
| | | | | | | | | | | |
Collapse
|
190
|
Dame JB, Yowell CA, Omara-Opyene L, Carlton JM, Cooper RA, Li T. Plasmepsin 4, the food vacuole aspartic proteinase found in all Plasmodium spp. infecting man. Mol Biochem Parasitol 2003; 130:1-12. [PMID: 14550891 DOI: 10.1016/s0166-6851(03)00137-3] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Plasmepsins are aspartic proteinases of the malaria parasite, and seven groups of plasmepsins have been identified by comparing genomic sequence data available for the genes encoding these enzymes from Plasmodium falciparum, Plasmodium vivax, Plasmodium knowlesi, Plasmodium berghei, and Plasmodium yoelii. The food vacuole plasmepsins typified by plasmepsin 4 from P. falciparum (PfPM4) constitute one of these groups. Genes encoding the ortholog of PfPM4 have been cloned from Plasmodium ovale, Plasmodium malariae, and P. vivax. In addition, P. falciparum contains three paralagous food vacuole plasmepsins or plasmepsin-like enzymes that appear to have arisen by gene duplication, plasmepsins 1 (PfPM1), 2 (PfPM2) and HAP, and all four were localized to purified food vacuole preparations by two-dimensional gel electrophoresis and mass spectroscopic analysis. The three paralogs of PfPM4 do not have counterparts in the six other Plasmodium spp. examined by genomic DNA blot analysis and by review of available genomic sequence data. The presence of these paralogs among the food vacuole plasmepsins in P. falciparum as compared with the other three species causing malaria in man will impact efforts to rationally design antimalarials targeting the food vacuole plasmepsins.
Collapse
Affiliation(s)
- John B Dame
- Department of Pathobiology, College of Veterinary Medicine, University of Florida, Box 110880, Gainesville, FL 32611-0880, USA.
| | | | | | | | | | | |
Collapse
|
191
|
Biagini GA, Bray PG, Spiller DG, White MRH, Ward SA. The digestive food vacuole of the malaria parasite is a dynamic intracellular Ca2+ store. J Biol Chem 2003; 278:27910-5. [PMID: 12740366 DOI: 10.1074/jbc.m304193200] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The acidic food vacuole of Plasmodium falciparum has been the subject of intense scientific investigation in the 40 years since its role in the digestion of host hemoglobin was first suggested. This proposed role has important implications for the complex host-parasite inter-relationship and also for the mode of action of several of the most effective antimalarial drugs. In addition, adaptive changes in the physiology of this organelle are implicated in drug resistance. Here we show that in addition to these functions, the digestive food vacuole of the malaria parasite is a dynamic internal store for free Ca2+, a role hitherto unsuspected. With the aid of live-cell laser scanning confocal imaging, spatiotemporal studies revealed that maintenance of elevated free Ca2+ in the digestive food vacuole (relative to cytosolic levels) is achieved by a thapsigargin (and cyclopiazonic acid)-sensitive Ca2+-pump in cooperation with a H+-dependent Ca2+ transporter. Redistribution of free cytosolic and vacuolar Ca2+ during parasite growth also suggests that vacuolar Ca2+ plays an essential role in parasite morphogenesis. These data imply that the digestive food vacuole of the malaria parasite is functionally akin to the vacuole of plants (tonoplast) and the small electron-dense granules of some parasites (acidocalcisomes) whereby H+-coupled Ca2+ transport is involved in ion transport, Ca2+ homeostasis, and signal transduction. These findings have significant implications for parasite development, antimalarial drug action, and mechanisms of drug resistance.
Collapse
Affiliation(s)
- Giancarlo A Biagini
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L35 QA, United Kingdom.
| | | | | | | | | |
Collapse
|
192
|
Mele R, Gomez Morales MA, Tosini F, Pozio E. Indinavir reduces Cryptosporidium parvum infection in both in vitro and in vivo models. Int J Parasitol 2003; 33:757-64. [PMID: 12814654 DOI: 10.1016/s0020-7519(03)00093-6] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The use of highly active antiretroviral therapy in persons with acquired immunodeficiency syndrome has reduced the prevalence of infection with Cryptosporidium parvum and the length and severity of its clinical course. This effect has in most cases been attributed to the recovery of the host immunity; however, some works suggest that human immunodeficiency virus protease inhibitors, indinavir in particular, which is one of the human immunodeficiency virus protease inhibitors used in highly active antiretroviral therapy, may be capable of controlling Microsporidia and Cryptosporidium infections, which are refractory to other treatments. The objective of the present study was to investigate the effect of human immunodeficiency virus protease inhibitors on C. parvum infections. Since preliminary experiments using ritonavir, saquinavir, and indinavir showed a drastic reduction of C. parvum infection both in vivo (neonatal Balb/c mice) and in vitro (human ileocecal adenocarcinoma tumour cell line) models, indinavir alone was tested in successive experiments. In vitro, the treatment of the sporulated oocysts with different concentrations of indinavir reduced the percentage of human ileocecal adenocarcinoma tumour cell line infected cells in a dose-dependent manner. For established infection, the treatment with 50 microM of indinavir decreased the percentage of infected cells in a time-dependent manner. In vivo, mice treated with indinavir at the same time they were infected with the oocysts showed a 93% reduction in the number of oocysts present in the entire intestinal contents and a 91% reduction in the number of intracellular parasites in the ileum. For established infection, indinavir treatment reduced the number of oocysts in the entire intestinal content by about 50% and the number of intracellular parasites in the ileum by about 70%. These data show that indinavir directly interferes with the cycle of C. parvum, resulting in a marked reduction in oocyst shedding and in the number of intracellular parasites. Protease inhibitors could be considered as good candidates for the treatment of cyptosporidiosis in immunosuppressed persons.
Collapse
Affiliation(s)
- R Mele
- Laboratory of Parasitology, Istituto Superiore di Sanità, viale Regina Elena 299, 00161 Rome, Italy
| | | | | | | |
Collapse
|
193
|
Banerjee R, Francis SE, Goldberg DE. Food vacuole plasmepsins are processed at a conserved site by an acidic convertase activity in Plasmodium falciparum. Mol Biochem Parasitol 2003; 129:157-65. [PMID: 12850260 DOI: 10.1016/s0166-6851(03)00119-1] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Intraerythrocytic Plasmodium falciparum digests vast amounts of hemoglobin within an acidic food vacuole (FV). Four homologous aspartic proteases participate in hemoglobin degradation within the FV. Plasmepsin (PM) I and II are thought to initiate degradation of the native hemoglobin molecule. PM IV and histo-aspartic protease (HAP) act on denatured globin further downstream in the pathway. PM I and II have been shown to be synthesized as zymogens and activated by proteolytic removal of a propiece. In this study, we have determined that the proteolytic processing of FV plasmepsins occurs immediately after a conserved Leu-Gly dipeptidyl motif with uniform kinetics and pH and inhibitor sensitivities. We have developed a cell-free in vitro processing assay that generates correctly processed plasmepsins. Our data suggest that proplasmepsin processing is not autocatalytic, but rather is mediated by a separate processing enzyme. This convertase requires acidic conditions and is blocked only by the calpain inhibitors, suggesting that it may be an atypical calpain-like protease.
Collapse
Affiliation(s)
- Ritu Banerjee
- Departments of Medicine and Molecular Microbiology, Howard Hughes Medical Institute, Washington University School of Medicine, Box 8230, 660 South Euclid Ave, St Louis, MO 63110, USA
| | | | | |
Collapse
|
194
|
Bernstein NK, Cherney MM, Yowell CA, Dame JB, James MNG. Structural insights into the activation of P. vivax plasmepsin. J Mol Biol 2003; 329:505-24. [PMID: 12767832 DOI: 10.1016/s0022-2836(03)00444-3] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The malarial aspartic proteinases (plasmepsins) have been discovered in several species of Plasmodium, including all four of the human malarial pathogens. In P.falciparum, plasmepsins I, II, IV and HAP have been directly implicated in hemoglobin degradation during malaria infection, and are now considered targets for anti-malarial drug design. The plasmepsins are produced from inactive zymogens, proplasmepsins, having unusually long N-terminal prosegments of more than 120 amino acids. Structural and biochemical evidence suggests that the conversion process of proplasmepsins to plasmepsins differs substantially from the gastric and plant aspartic proteinases. Instead of blocking substrate access to a pre-formed active site, the prosegment enforces a conformation in which proplasmepsin cannot form a functional active site. We have determined crystal structures of plasmepsin and proplasmepsin from P.vivax. The three-dimensional structure of P.vivax plasmepsin is typical of the monomeric aspartic proteinases, and the structure of P.vivax proplasmepsin is similar to that of P.falciparum proplasmepsin II. A dramatic refolding of the mature N terminus and a large (18 degrees ) reorientation of the N-domain between P.vivax proplasmepsin and plasmepsin results in a severe distortion of the active site region of the zymogen relative to that of the mature enzyme. The present structures confirm that the mode of inactivation observed originally in P.falciparum proplasmepsin II, i.e. an incompletely formed active site, is a true structural feature and likely represents the general mode of inactivation of the related proplasmepsins.
Collapse
Affiliation(s)
- Nina Khazanovich Bernstein
- CIHR Group in Protein Structure and Function, Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada T6G 2H7
| | | | | | | | | |
Collapse
|
195
|
Batra S, Sabnis YA, Rosenthal PJ, Avery MA. Structure-based approach to falcipain-2 inhibitors: synthesis and biological evaluation of 1,6,7-trisubstituted dihydroisoquinolines and isoquinolines. Bioorg Med Chem 2003; 11:2293-9. [PMID: 12713840 DOI: 10.1016/s0968-0896(03)00117-2] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
1,4,7-Trisubstituted isoquinolines were designed, synthesized and evaluated for their inhibition against Plasmodium falciparum cysteine protease falcipain-2. The 1-benzyloxyphenyl-dihydroisoquinoline and -isoquinoline derivatives were found to exhibit better activity against falcipain-2 than their corresponding 1-hydroxyphenyl or 1-methoxyphenyl analogues. The docking scores correlate with the IC(50) values of compounds and give a high coefficient correlation of 0.94.
Collapse
Affiliation(s)
- Sanjay Batra
- Medicinal Chemistry Division, Central Drug Research Institute, 226001 Lucknow, India.
| | | | | | | |
Collapse
|
196
|
Oscarsson K, Oscarson S, Vrang L, Hamelink E, Hallberg A, Samuelsson B. New potent C2-symmetric malaria plasmepsin I and II inhibitors. Bioorg Med Chem 2003; 11:1235-46. [PMID: 12628651 DOI: 10.1016/s0968-0896(02)00643-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
A series of malaria plasmepsin (Plm) I and II inhibitors containing a C(2)-symmetric core structure have been synthesised and tested for protease inhibition activity. These compounds can be prepared using a straightforward synthesis involving a phenol nucleophilic ring opening of a diepoxide. Exemplar compounds synthesised exhibited remarkable inhibitory activity against both Plm I and II, notably 15c with K(i) values of 2.7nM and 0.25nM respectively, as well as showing >100-fold selectivity against Cathepsin D.
Collapse
Affiliation(s)
- Karin Oscarsson
- Department of Organic Chemistry, Arrhenius Laboratory, Floor 6, Stockholm University, S-106 91, Stockholm, Sweden.
| | | | | | | | | | | |
Collapse
|
197
|
Wu Y, Wang X, Liu X, Wang Y. Data-mining approaches reveal hidden families of proteases in the genome of malaria parasite. Genome Res 2003; 13:601-16. [PMID: 12671001 PMCID: PMC430172 DOI: 10.1101/gr.913403] [Citation(s) in RCA: 170] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The search for novel antimalarial drug targets is urgent due to the growing resistance of Plasmodium falciparum parasites to available drugs. Proteases are attractive antimalarial targets because of their indispensable roles in parasite infection and development, especially in the processes of host erythrocyte rupture/invasion and hemoglobin degradation. However, to date, only a small number of proteases have been identified and characterized in Plasmodium species. Using an extensive sequence similarity search, we have identified 92 putative proteases in the P. falciparum genome. A set of putative proteases including calpain, metacaspase, and signal peptidase I have been implicated to be central mediators for essential parasitic activity and distantly related to the vertebrate host. Moreover, of the 92, at least 88 have been demonstrated to code for gene products at the transcriptional levels, based upon the microarray and RT-PCR results, and the publicly available microarray and proteomics data. The present study represents an initial effort to identify a set of expressed, active, and essential proteases as targets for inhibitor-based drug design.
Collapse
Affiliation(s)
- Yimin Wu
- Department of Protistology, American Type Culture Collection, Manassas, Virginia 20110, USA
| | | | | | | |
Collapse
|
198
|
Dahlgren A, Kvarnström I, Vrang L, Hamelink E, Hallberg A, Rosenquist A, Samuelsson B. Solid-phase library synthesis of reversed-statine type inhibitors of the malarial aspartyl proteases plasmepsin I and II. Bioorg Med Chem 2003; 11:827-41. [PMID: 12614868 DOI: 10.1016/s0968-0896(02)00568-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
With the aim to develop inhibitors of the plasmepsin I and II aspartic proteases of the malaria parasite Plasmodium falciparum, we have synthesized sets of libraries from novel reversed-statine isosteres, using a combination of solution phase and solid phase chemistry. The synthetic strategy furnishes the library compounds in good to high overall yields and with excellent stereochemical control throughout the developed route. The products were evaluated for their plasmepsin I and II inhibiting properties and were found to exhibit modest but promising activity. The best inhibitor exhibits an in vitro activity of 28% inhibition of plasmepsin II at an inhibitor concentration of 0.5 microM (K(i) for Plm II=5.4 microM).
Collapse
Affiliation(s)
- Anders Dahlgren
- Department of Chemistry, Linköping University, S-581 83 Linköping, Sweden
| | | | | | | | | | | | | |
Collapse
|
199
|
Chapter 21. New therapies for malaria. ANNUAL REPORTS IN MEDICINAL CHEMISTRY 2003. [DOI: 10.1016/s0065-7743(03)38022-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
|
200
|
Bozdech Z, Zhu J, Joachimiak MP, Cohen FE, Pulliam B, DeRisi JL. Expression profiling of the schizont and trophozoite stages of Plasmodium falciparum with a long-oligonucleotide microarray. Genome Biol 2003; 4:R9. [PMID: 12620119 PMCID: PMC151308 DOI: 10.1186/gb-2003-4-2-r9] [Citation(s) in RCA: 262] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2002] [Revised: 10/10/2002] [Accepted: 12/05/2002] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The worldwide persistence of drug-resistant Plasmodium falciparum, the most lethal variety of human malaria, is a global health concern. The P. falciparum sequencing project has brought new opportunities for identifying molecular targets for antimalarial drug and vaccine development. RESULTS We developed a software package, ArrayOligoSelector, to design an open reading frame (ORF)-specific DNA microarray using the publicly available P. falciparum genome sequence. Each gene was represented by one or more long 70 mer oligonucleotides selected on the basis of uniqueness within the genome, exclusion of low-complexity sequence, balanced base composition and proximity to the 3' end. A first-generation microarray representing approximately 6,000 ORFs of the P. falciparum genome was constructed. Array performance was evaluated through the use of control oligonucleotide sets with increasing levels of introduced mutations, as well as traditional northern blotting. Using this array, we extensively characterized the gene-expression profile of the intraerythrocytic trophozoite and schizont stages of P. falciparum. The results revealed extensive transcriptional regulation of genes specialized for processes specific to these two stages. CONCLUSIONS DNA microarrays based on long oligonucleotides are powerful tools for the functional annotation and exploration of the P. falciparum genome. Expression profiling of trophozoites and schizonts revealed genes associated with stage-specific processes and may serve as the basis for future drug targets and vaccine development.
Collapse
Affiliation(s)
- Zbynek Bozdech
- Department of Biochemistry and Biophysics, University of California San Francisco, 513 Parnassus Ave, San Francisco, CA 94143-0448, USA
| | - Jingchun Zhu
- Department of Biochemistry and Biophysics, University of California San Francisco, 513 Parnassus Ave, San Francisco, CA 94143-0448, USA
| | - Marcin P Joachimiak
- Department of Molecular and Cellular Pharmacology, University of California San Francisco, 513 Parnassus Ave, San Francisco, CA 94143-0448, USA
| | - Fred E Cohen
- Department of Molecular and Cellular Pharmacology, University of California San Francisco, 513 Parnassus Ave, San Francisco, CA 94143-0448, USA
| | - Brian Pulliam
- Department of Biochemistry and Biophysics, University of California San Francisco, 513 Parnassus Ave, San Francisco, CA 94143-0448, USA
| | - Joseph L DeRisi
- Department of Biochemistry and Biophysics, University of California San Francisco, 513 Parnassus Ave, San Francisco, CA 94143-0448, USA
| |
Collapse
|