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Nasamu AS, Polino AJ, Istvan ES, Goldberg DE. Malaria parasite plasmepsins: More than just plain old degradative pepsins. J Biol Chem 2020; 295:8425-8441. [PMID: 32366462 PMCID: PMC7307202 DOI: 10.1074/jbc.rev120.009309] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Plasmepsins are a group of diverse aspartic proteases in the malaria parasite Plasmodium Their functions are strikingly multifaceted, ranging from hemoglobin degradation to secretory organelle protein processing for egress, invasion, and effector export. Some, particularly the digestive vacuole plasmepsins, have been extensively characterized, whereas others, such as the transmission-stage plasmepsins, are minimally understood. Some (e.g. plasmepsin V) have exquisite cleavage sequence specificity; others are fairly promiscuous. Some have canonical pepsin-like aspartic protease features, whereas others have unusual attributes, including the nepenthesin loop of plasmepsin V and a histidine in place of a catalytic aspartate in plasmepsin III. We have learned much about the functioning of these enzymes, but more remains to be discovered about their cellular roles and even their mechanisms of action. Their importance in many key aspects of parasite biology makes them intriguing targets for antimalarial chemotherapy. Further consideration of their characteristics suggests that some are more viable drug targets than others. Indeed, inhibitors of invasion and egress offer hope for a desperately needed new drug to combat this nefarious organism.
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Affiliation(s)
- Armiyaw S Nasamu
- Division of Infectious Diseases, Departments of Medicine and Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Alexander J Polino
- Division of Infectious Diseases, Departments of Medicine and Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Eva S Istvan
- Division of Infectious Diseases, Departments of Medicine and Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Daniel E Goldberg
- Division of Infectious Diseases, Departments of Medicine and Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
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2
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Rathore I, Mishra V, Patel C, Xiao H, Gustchina A, Wlodawer A, Yada RY, Bhaumik P. Activation mechanism of plasmepsins, pepsin-like aspartic proteases from Plasmodium, follows a unique trans-activation pathway. FEBS J 2020; 288:678-698. [PMID: 32385863 DOI: 10.1111/febs.15363] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2020] [Revised: 04/11/2020] [Accepted: 05/05/2020] [Indexed: 11/29/2022]
Abstract
Plasmodium parasites that cause malaria produce plasmepsins (PMs), pepsin-like aspartic proteases that are important antimalarial drug targets due to their role in host hemoglobin degradation. The enzymes are synthesized as inactive zymogens (pro-PMs), and the mechanism of their conversion to the active, mature forms has not been clearly elucidated. Our structural investigations of vacuolar pro-PMs with truncated prosegment (pro-tPMs) reveal that the formation of the S-shaped dimer is their innate property. Further structural studies, biochemical analysis, and molecular dynamics simulations indicate that disruption of the Tyr-Asp loop (121p-4), coordinated with the movement of the loop L1 (237-247) and helix H2 (101p-113p), is responsible for the extension of the pro-mature region (harboring the cleavage site). Consequently, under acidic pH conditions, these structural changes result in the dissociation of the dimers to monomers and the protonation of the residues in the prosegment prompts its unfolding. Subsequently, we demonstrated that the active site of the monomeric pro-tPMs with the unfolded prosegment is accessible for peptide substrate binding; in contrast, the active site is blocked in folded prosegment form of pro-tPMs. Thus, we propose a novel mechanism of auto-activation of vacuolar pro-tPMs that under acidic conditions can form a catalytically competent active site. One monomer cleaves the prosegment of the other one through a trans-activation process, resulting in formation of mature enzyme. As a result, once a mature enzyme is generated, it leads to the complete conversion of all the inactive pro-tPMs to their mature form. DATABASE: Atomic coordinates and structure factors have been submitted in the Protein Data Bank (PDB) under the PDB IDs 6KUB, 6KUC, and 6KUD.
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Affiliation(s)
- Ishan Rathore
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, India
| | - Vandana Mishra
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, India
| | - Chandan Patel
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai, India
| | - Huogen Xiao
- Summerland Research and Development Centre, Agriculture and Agri-Food Canada, Summerland, BC, Canada
| | - Alla Gustchina
- Protein Structure Section, Macromolecular Crystallography Laboratory, National Cancer Institute, Frederick, MD, USA
| | - Alexander Wlodawer
- Protein Structure Section, Macromolecular Crystallography Laboratory, National Cancer Institute, Frederick, MD, USA
| | - Rickey Y Yada
- Faculty of Land and Food Systems, University of British Columbia, Vancouver, BC, Canada
| | - Prasenjit Bhaumik
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, India
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3
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Yield improvement and enzymatic dissection of Plasmodium falciparum plasmepsin V. Mol Biochem Parasitol 2019; 231:111188. [PMID: 31108131 DOI: 10.1016/j.molbiopara.2019.111188] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Revised: 05/13/2019] [Accepted: 05/15/2019] [Indexed: 11/22/2022]
Abstract
To survive within a red blood cell (RBC), malaria parasites establish striking modifications to the permeability, rigidity and cytoadherence properties of the host cell. This is mediated by the export of hundreds of proteins from the parasite into the erythrocyte. Plasmodium falciparum plasmepsin V (PfPMV), is an ER resident aspartic protease that processes proteins for export into the host erythrocyte, plays a crucial role in parasite virulence and survival and is considered a potential malaria drug target. Most attempts at its heterologous expression in Escherichia coli have resulted in mainly the production of insoluble proteins. In this study, we employed a multipurpose fusion tag to improve the production of PfPMV in E. coli. Recombinant PfPMVm, comprising residues 84-521, was substantially obtained in soluble form and could be purified in a single step, yielding a 3.7-fold increase in purified PfPMVm compared to previous reports. Additionally, we have mutated the catalytic residues (D118N and D365N), individually and together, and the unpaired cysteine residue C178 to evaluate the effects on catalytic efficiency. Mutation of D365 had more pronounced effects on the catalytic efficiency than that of D118, suggesting that the D365 may act as a catalytic nucleophile to activate the water molecule. The importance of C178 was also confirmed by the inhibition by metal ions, indicating that C178 is partially involved in the substrate recognition. Collectively, our results describe an improved system to produce recombinant PfPMVm in E. coli and dissect the amino acids involved in catalysis and substrate recognition.
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Singh S, Rajendran V, He J, Singh AK, Achieng AO, Vandana, Pant A, Nasamu AS, Pandit M, Singh J, Quadiri A, Gupta N, Poonam, Ghosh PC, Singh BK, Narayanan L, Kempaiah P, Chandra R, Dunn BM, Pandey KC, Goldberg DE, Singh AP, Rathi B. Fast-Acting Small Molecules Targeting Malarial Aspartyl Proteases, Plasmepsins, Inhibit Malaria Infection at Multiple Life Stages. ACS Infect Dis 2019; 5:184-198. [PMID: 30554511 DOI: 10.1021/acsinfecdis.8b00197] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The eradication of malaria remains challenging due to the complex life cycle of Plasmodium and the rapid emergence of drug-resistant forms of Plasmodium falciparum and Plasmodium vivax. New, effective, and inexpensive antimalarials against multiple life stages of the parasite are urgently needed to combat the spread of malaria. Here, we synthesized a set of novel hydroxyethylamines and investigated their activities in vitro and in vivo. All of the compounds tested had an inhibitory effect on the blood stage of P. falciparum at submicromolar concentrations, with the best showing 50% inhibitory concentrations (IC50) of around 500 nM against drug-resistant P. falciparum parasites. These compounds showed inhibitory actions against plasmepsins, a family of malarial aspartyl proteases, and exhibited a marked killing effect on blood stage Plasmodium. In chloroquine-resistant Plasmodium berghei and P. berghei ANKA infected mouse models, treating mice with both compounds led to a significant decrease in blood parasite load. Importantly, two of the compounds displayed an inhibitory effect on the gametocyte stages (III-V) of P. falciparum in culture and the liver-stage infection of P. berghei both in in vitro and in vivo. Altogether, our findings suggest that fast-acting hydroxyethylamine-phthalimide analogs targeting multiple life stages of the parasite could be a valuable chemical lead for the development of novel antimalarial drugs.
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Affiliation(s)
- Snigdha Singh
- Laboratory for Translational Chemistry and Drug Discovery, Department of Chemistry, Hansraj College University Enclave, University of Delhi, Delhi 110007, India
- Department of Chemistry, University of Delhi, Delhi 110007, India
| | - Vinoth Rajendran
- Department of Biochemistry, University of Delhi South Campus, New Delhi 110021, India
| | - Jiang He
- Institute for Medical Engineering and Science, Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Amit K. Singh
- Department of Chemistry, University of Delhi, Delhi 110007, India
| | - Angela O. Achieng
- Center for Global Health, Department of Internal Medicine, University of New Mexico Health Sciences Center, Albuquerque, New Mexico 87131, United States
| | - Vandana
- Host−Parasite Interaction Biology Group, National Institute of Malaria Research, Lab. No. 219, Sector-8 Dwarka, New Delhi 110077, India
| | - Akansha Pant
- Host−Parasite Interaction Biology Group, National Institute of Malaria Research, Lab. No. 219, Sector-8 Dwarka, New Delhi 110077, India
| | - Armiyaw S. Nasamu
- Departments of Medicine and Molecular Microbiology, Washington University School of Medicine, St Louis, Missouri 63110, United States
| | - Mansi Pandit
- Bioinformatics Infrastructure Facility, Sri Venkateswara College, University of Delhi South Campus, New Delhi 110021, India
| | - Jyoti Singh
- Infectious Diseases Laboratory, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Afshana Quadiri
- Infectious Diseases Laboratory, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Nikesh Gupta
- Special Centre for Nanosciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - Poonam
- Department of Chemistry, Miranda House, University of Delhi North Campus, Delhi 110007, India
| | - Prahlad C. Ghosh
- Department of Biochemistry, University of Delhi South Campus, New Delhi 110021, India
| | | | - Latha Narayanan
- Bioinformatics Infrastructure Facility, Sri Venkateswara College, University of Delhi South Campus, New Delhi 110021, India
| | - Prakasha Kempaiah
- Center for Global Health, Department of Internal Medicine, University of New Mexico Health Sciences Center, Albuquerque, New Mexico 87131, United States
- Department of Medicine, Loyola University Stritch School of Medicine, 2160 South First Avenue, Chicago, Illinois 60153, United States
| | - Ramesh Chandra
- Department of Chemistry, University of Delhi, Delhi 110007, India
| | - Ben M. Dunn
- Department of Biochemistry & Molecular Biology, University of Florida College of Medicine, P.O. Box 100245, Gainesville, Florida 32610, United States
| | - Kailash C. Pandey
- Host−Parasite Interaction Biology Group, National Institute of Malaria Research, Lab. No. 219, Sector-8 Dwarka, New Delhi 110077, India
- Department of Biochemistry, National Institute for Research in Environmental Health, ICMR, Bhopal 462001, India
| | - Daniel E. Goldberg
- Departments of Medicine and Molecular Microbiology, Washington University School of Medicine, St Louis, Missouri 63110, United States
| | - Agam P. Singh
- Infectious Diseases Laboratory, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Brijesh Rathi
- Laboratory for Translational Chemistry and Drug Discovery, Department of Chemistry, Hansraj College University Enclave, University of Delhi, Delhi 110007, India
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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5
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Meissner KA, Kronenberger T, Maltarollo VG, Trossini GHG, Wrenger C. Targeting the Plasmodium falciparum plasmepsin V by ligand-based virtual screening. Chem Biol Drug Des 2018; 93:300-312. [PMID: 30320974 DOI: 10.1111/cbdd.13416] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 06/05/2018] [Accepted: 06/09/2018] [Indexed: 12/16/2022]
Abstract
Malaria is a devastating disease depending only on chemotherapy as treatment. However, medication is losing efficacy, and therefore, there is an urgent need for the discovery of novel pharmaceutics. Recently, plasmepsin V, an aspartic protease anchored in the endoplasmaic reticulum, was demonstrated as responsible for the trafficking of parasite-derived proteins to the erythrocytic surface and further validated as a drug target. In this sense, ligand-based virtual screening has been applied to design inhibitors that target plasmepsin V of P. falciparum (PMV). After screening 5.5 million compounds, four novel plasmepsin inhibitors have been identified which were subsequently analyzed for the potency at the cellular level. Since PMV is membrane-anchored, the verification in vivo by using transgenic PMV overexpressing P. falciparum cells has been performed in order to evaluate drug efficacy. Two lead compounds, revealing IC50 values were 44.2 and 19.1 μm, have been identified targeting plasmepsin V in vivo and do not significantly affect the cell viability of human cells up to 300 μm. We herein report the use of the consensus of individual virtual screening as a new technique to design new ligands, and we propose two new lead compounds as novel protease inhibitors to target malaria.
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Affiliation(s)
- Kamila Anna Meissner
- Unit for Drug Discovery, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
| | - Thales Kronenberger
- Unit for Drug Discovery, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil.,Department of Internal Medicine VIII, University Hospital of Tübingen, Tübingen, Germany
| | - Vinícius Gonçalves Maltarollo
- Department of Pharmaceutical Products, Faculty of Pharmacy, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | | | - Carsten Wrenger
- Unit for Drug Discovery, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
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Mishra V, Rathore I, Arekar A, Sthanam LK, Xiao H, Kiso Y, Sen S, Patankar S, Gustchina A, Hidaka K, Wlodawer A, Yada RY, Bhaumik P. Deciphering the mechanism of potent peptidomimetic inhibitors targeting plasmepsins - biochemical and structural insights. FEBS J 2018; 285:3077-3096. [PMID: 29943906 DOI: 10.1111/febs.14598] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Revised: 06/10/2018] [Accepted: 06/22/2018] [Indexed: 11/28/2022]
Abstract
Malaria is a deadly disease killing worldwide hundreds of thousands people each year and the responsible parasite has acquired resistance to the available drug combinations. The four vacuolar plasmepsins (PMs) in Plasmodium falciparum involved in hemoglobin (Hb) catabolism represent promising targets to combat drug resistance. High antimalarial activities can be achieved by developing a single drug that would simultaneously target all the vacuolar PMs. We have demonstrated for the first time the use of soluble recombinant plasmepsin II (PMII) for structure-guided drug discovery with KNI inhibitors. Compounds used in this study (KNI-10742, 10743, 10395, 10333, and 10343) exhibit nanomolar inhibition against PMII and are also effective in blocking the activities of PMI and PMIV with the low nanomolar Ki values. The high-resolution crystal structures of PMII-KNI inhibitor complexes reveal interesting features modulating their differential potency. Important individual characteristics of the inhibitors and their importance for potency have been established. The alkylamino analog, KNI-10743, shows intrinsic flexibility at the P2 position that potentiates its interactions with Asp132, Leu133, and Ser134. The phenylacetyl tripeptides, KNI-10333 and KNI-10343, accommodate different ρ-substituents at the P3 phenylacetyl ring that determine the orientation of the ring, thus creating novel hydrogen-bonding contacts. KNI-10743 and KNI-10333 possess significant antimalarial activity, block Hb degradation inside the food vacuole, and show no cytotoxicity on human cells; thus, they can be considered as promising candidates for further optimization. Based on our structural data, novel KNI derivatives with improved antimalarial activity could be designed for potential clinical use. DATABASE: Structural data are available in the PDB under the accession numbers 5YIE, 5YIB, 5YID, 5YIC, and 5YIA.
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Affiliation(s)
- Vandana Mishra
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, India
| | - Ishan Rathore
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, India
| | - Anagha Arekar
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, India
| | - Lakshmi Kavitha Sthanam
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, India
| | - Huogen Xiao
- Department of Molecular and Cellular Biology, University of Guelph, ON, Canada
| | - Yoshiaki Kiso
- Laboratory of Peptide Sciences, Nagahama Institute of Bio-Science and Technology, Japan
| | - Shamik Sen
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, India
| | - Swati Patankar
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, India
| | - Alla Gustchina
- Protein Structure Section, Macromolecular Crystallography Laboratory, National Cancer Institute, Frederick, MD, USA
| | - Koushi Hidaka
- Division of Pharmaceutical Chemistry, Faculty of Pharmaceutical Sciences, Kobe Gakuin University, Japan
| | - Alexander Wlodawer
- Protein Structure Section, Macromolecular Crystallography Laboratory, National Cancer Institute, Frederick, MD, USA
| | - Rickey Y Yada
- Faculty of Land and Food Systems, University of British Columbia, Vancouver, BC, Canada
| | - Prasenjit Bhaumik
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, India
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7
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Sittikul P, Songtawee N, Kongkathip N, Boonyalai N. In vitro and in silico studies of naphthoquinones and peptidomimetics toward Plasmodium falciparum plasmepsin V. Biochimie 2018; 152:159-173. [PMID: 30103899 DOI: 10.1016/j.biochi.2018.07.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Accepted: 07/04/2018] [Indexed: 12/16/2022]
Abstract
Plasmodium proteases play both regulatory and effector roles in essential biological processes in this important pathogen and have long been investigated as drug targets. Plasmepsin V from P. falciparum (PfPMV) is an essential protease that processes proteins for export into the host erythrocyte and is a focus of ongoing drug development efforts. In the present study, recombinant protein production, inhibition assays, binding studies as well as molecular docking and molecular dynamics simulation studies were used to investigate the mode of binding of a PEXEL-based peptidomimetic and naphthoquinone compounds to PfPMV. Consistent with our previous study, refolded PfPMVs were produced with functional characteristics similar to the soluble counterpart. Naphthoquinone compounds inhibited PfPMV activity by 50% at 50 μM but did not affect pepsin activity. The IC50 values of compounds 31 and 37 against PfPMV were 22.25 and 68.94 μM, respectively. Molecular dynamics simulations revealed that PEXEL peptide interacted with PfPMV active site residues via electrostatic interactions while naphthoquinone binding preferred van der Waal interactions. P1'-Ser of the PfEMP2 substrate formed an additional H-bond with Asp365 promoting the catalytic efficiency. Additionally, the effect of metal ions on the secondary structure of PfPMV was examined. Our results confirmed that Hg2+ ions reversibly induced the changes in secondary structure of the protein whereas Fe3+ ions induced irreversibly. No change was observed in the presence of Ca2+ ions. Overall, the results here suggested that naphthoquinone derivatives may represent another source of antimalarial inhibitors targeting aspartic proteases but further chemical modifications are required.
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Affiliation(s)
- Pichamon Sittikul
- Department of Biochemistry, Faculty of Science, Kasetsart University, Chatuchak, Bangkok, 10900, Thailand; Department of Tropical Pediatrics, Faculty of Tropical Medicine, Mahidol University, Bangkok, 10400, Thailand
| | - Napat Songtawee
- Department of Clinical Chemistry, Faculty of Medical Technology, Mahidol University, Phuttamonthon, Nakhon Pathom, 73170, Thailand
| | - Ngampong Kongkathip
- Natural Product and Organic Synthesis Research Unit (NPOS), Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Kasetsart University, Chatuchak, Bangkok, 10900, Thailand
| | - Nonlawat Boonyalai
- Department of Biochemistry, Faculty of Science, Kasetsart University, Chatuchak, Bangkok, 10900, Thailand.
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The prosegment catalyzes native folding of Plasmodium falciparum plasmepsin II. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2016; 1864:1356-62. [DOI: 10.1016/j.bbapap.2016.06.019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Revised: 06/29/2016] [Accepted: 06/30/2016] [Indexed: 01/15/2023]
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Understanding the structural basis of substrate recognition by Plasmodium falciparum plasmepsin V to aid in the design of potent inhibitors. Sci Rep 2016; 6:31420. [PMID: 27531685 PMCID: PMC4987639 DOI: 10.1038/srep31420] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 07/20/2016] [Indexed: 11/16/2022] Open
Abstract
Plasmodium falciparum plasmepsin V (PfPMV) is an essential aspartic protease required for parasite survival, thus, considered as a potential drug target. This study reports the first detailed structural analysis and molecular dynamics simulation of PfPMV as an apoenzyme and its complexes with the substrate PEXEL as well as with the inhibitor saquinavir. The presence of pro-peptide in PfPMV may not structurally hinder the formation of a functionally competent catalytic active site. The structure of PfPMV-PEXEL complex shows that the unique positions of Glu179 and Gln222 are responsible for providing the specificity of PEXEL substrate with arginine at P3 position. The structural analysis also reveals that the S4 binding pocket in PfPMV is occupied by Ile94, Ala98, Phe370 and Tyr472, and therefore, does not allow binding of pepstatin, a potent inhibitor of most pepsin-like aspartic proteases. Among the screened inhibitors, the HIV-1 protease inhibitors and KNI compounds have higher binding affinities for PfPMV with saquinavir having the highest value. The presence of a flexible group at P2 and a bulky hydrophobic group at P3 position of the inhibitor is preferred in the PfPMV substrate binding pocket. Results from the present study will aid in the design of potent inhibitors of PMV.
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Sappakhaw K, Takasila R, Sittikul P, Wattana-Amorn P, Assavalapsakul W, Boonyalai N. Biochemical characterization of plasmepsin V from Plasmodium vivax Thailand isolates: Substrate specificity and enzyme inhibition. Mol Biochem Parasitol 2016; 204:51-63. [PMID: 26795263 DOI: 10.1016/j.molbiopara.2016.01.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2015] [Revised: 01/05/2016] [Accepted: 01/08/2016] [Indexed: 12/19/2022]
Abstract
Plasmepsin V (PMV) is a Plasmodium aspartic protease responsible for the cleavage of the Plasmodium export element (PEXEL) motif, which is an essential step for export of PEXEL containing proteins and crucial for parasite viability. Here we describe the genetic polymorphism of Plasmodium vivax PMV (PvPMV) Thailand isolates, followed by cloning, expression, purification and characterization of PvPMV-Thai, presenting the pro- and mature-form of PvPMV-Thai. With our refolding and purification method, approximately 1mg of PvPMV-Thai was obtained from 1g of washed inclusion bodies. Unlike PvPMV-Ind and PvPMV-Sal-1, PvPMV-Thai contains a four-amino acid insertion (SVSE) at residues 246-249. We have confirmed that this insertion did not interfere with the catalytic activity as it is located in the long loop (R241-E272) pointing away from the substrate-binding pocket. PvPMV-Thai exhibited similar activity to PfPMV counterparts in which PfEMP2 could be hydrolyzed more efficiently than HRPII. Substrate specificity studies at P1' showed that replacing Ser by Val or Glu of the PfEMP2 peptide markedly reduced the enzyme activity of PvPMV similar to that of PfPMV whereas replacing His by Val or Ser of the HRPII peptide increased the cleavage activity. However, the substitution of amino acids at the P2 position with Glu dramatically reduced the cleavage efficiency by 80% in PvPMV in contrast to 30% in PfPMV, indicating subtle differences around the S2 binding pocket of both PfPMV and PvPMV. Four inhibitors were also evaluated for PvPMV-Thai activity including PMSF, pepstatin A, nelfinavir, and menisporopsin A-a macrocyclic polylactone. We are the first to show that menisporopsin A partially inhibits the PvPMV-Thai activity at high concentration. Taken together, these findings provide insights into recombinant production, substrate specificity and inhibition of PvPMV-Thai.
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Affiliation(s)
- Khomkrit Sappakhaw
- Department of Biochemistry, Special Research Unit for Protein Engineering and Protein Bioinformatics, Faculty of Science, Kasetsart University, 50 Ngam Wong Wan Road, Lat Yao, Chatuchak, Bangkok 10900, Thailand
| | - Ratchaneekorn Takasila
- Department of Biochemistry, Special Research Unit for Protein Engineering and Protein Bioinformatics, Faculty of Science, Kasetsart University, 50 Ngam Wong Wan Road, Lat Yao, Chatuchak, Bangkok 10900, Thailand
| | - Pichamon Sittikul
- Department of Biochemistry, Special Research Unit for Protein Engineering and Protein Bioinformatics, Faculty of Science, Kasetsart University, 50 Ngam Wong Wan Road, Lat Yao, Chatuchak, Bangkok 10900, Thailand
| | - Pakorn Wattana-Amorn
- Center of Excellence for Innovation in Chemistry, Faculty of Science, Kasetsart University, 50 Ngam Wong Wan Road, Lat Yao, Chatuchak, Bangkok 10900, Thailand; Department of Chemistry, Faculty of Science, Kasetsart University, 50 Ngam Wong Wan Road, Lat Yao, Chatuchak, Bangkok 10900, Thailand
| | - Wanchai Assavalapsakul
- Department of Microbiology, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
| | - Nonlawat Boonyalai
- Department of Biochemistry, Special Research Unit for Protein Engineering and Protein Bioinformatics, Faculty of Science, Kasetsart University, 50 Ngam Wong Wan Road, Lat Yao, Chatuchak, Bangkok 10900, Thailand; Center of Excellence for Innovation in Chemistry, Faculty of Science, Kasetsart University, 50 Ngam Wong Wan Road, Lat Yao, Chatuchak, Bangkok 10900, Thailand.
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Long Y, Cao B, Yu L, Tukayo M, Feng C, Wang Y, Luo D. Angiostrongylus cantonensis cathepsin B-like protease (Ac-cathB-1) is involved in host gut penetration. ACTA ACUST UNITED AC 2015; 22:37. [PMID: 26682577 PMCID: PMC4684300 DOI: 10.1051/parasite/2015037] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2015] [Accepted: 11/27/2015] [Indexed: 12/17/2022]
Abstract
Although the global spread of the emerging zoonosis, human angiostrongyliasis, has attracted increasing attention, understanding of specific gene function has been impeded by the inaccessibility of genetic manipulation of the pathogen nematode causing this disease, Angiostrongylus cantonensis. Many parasitic proteases play key roles in host-parasite interactions, but those of A. cantonensis are always expressed as the inactive form in prokaryotic expression systems, thereby impeding functional studies. Hence, a lentiviral system that drives secreted expression of target genes fused to a Myc-His tag was used to obtain recombinant Ac-cathB-1 with biological activity. Although this class of proteases was always reported to function in nutrition and immune evasion in parasitic nematodes, recombinant Ac-cathB-1 was capable of hydrolysis of fibronectin and laminin as well as the extracellular matrix of IEC-6 monolayer, so that the intercellular space of the IEC-6 monolayer increased 5.15 times as compared to the control, while the shape of the adherent cells partly rounded up. This suggests a probable role for this protease in intestinal epithelial penetration. The inhibition of Ac-cathB-1 enzymatic activity with antiserum partly suppressed larval penetration ability in the isolated intestine. Thus, an effective system for heterologous expression of parasite proteases is presented for studying gene function in A. cantonensis; and Ac-cathB-1 was related to larval penetration ability in the host small intestine.
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Affiliation(s)
- Ying Long
- School of Life Sciences, Xiamen University, Fujian 361102, P.R. China - State Key Laboratory of Cellular Stress Biology, Xiamen University, Fujian 361102, P.R. China
| | - Binbin Cao
- School of Life Sciences, Xiamen University, Fujian 361102, P.R. China - State Key Laboratory of Cellular Stress Biology, Xiamen University, Fujian 361102, P.R. China
| | - Liang Yu
- School of Life Sciences, Xiamen University, Fujian 361102, P.R. China - State Key Laboratory of Cellular Stress Biology, Xiamen University, Fujian 361102, P.R. China
| | - Meks Tukayo
- School of Life Sciences, Xiamen University, Fujian 361102, P.R. China - State Key Laboratory of Cellular Stress Biology, Xiamen University, Fujian 361102, P.R. China
| | - Chonglv Feng
- School of Life Sciences, Xiamen University, Fujian 361102, P.R. China - State Key Laboratory of Cellular Stress Biology, Xiamen University, Fujian 361102, P.R. China
| | - Yinan Wang
- Medical College, Xiamen University, Fujian 361102, P.R. China
| | - Damin Luo
- School of Life Sciences, Xiamen University, Fujian 361102, P.R. China - State Key Laboratory of Cellular Stress Biology, Xiamen University, Fujian 361102, P.R. China
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13
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Liu P, Robbins AH, Marzahn MR, McClung SH, Yowell CA, Stevens SM, Dame JB, Dunn BM. Enzymatic Characterization of Recombinant Food Vacuole Plasmepsin 4 from the Rodent Malaria Parasite Plasmodium berghei. PLoS One 2015; 10:e0141758. [PMID: 26510189 PMCID: PMC4624963 DOI: 10.1371/journal.pone.0141758] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Accepted: 10/12/2015] [Indexed: 01/17/2023] Open
Abstract
The rodent malaria parasite Plasmodium berghei is a practical model organism for experimental studies of human malaria. Plasmepsins are a class of aspartic proteinase isoforms that exert multiple pathological effects in malaria parasites. Plasmepsins residing in the food vacuole (FV) of the parasite hydrolyze hemoglobin in red blood cells. In this study, we cloned PbPM4, the FV plasmepsin gene of P. berghei that encoded an N-terminally truncated pro-segment and the mature enzyme from genomic DNA. We over-expressed this PbPM4 zymogen as inclusion bodies (IB) in Escherichia coli, and purified the protein following in vitro IB refolding. Auto-maturation of the PbPM4 zymogen to mature enzyme was carried out at pH 4.5, 5.0, and 5.5. Interestingly, we found that the PbPM4 zymogen exhibited catalytic activity regardless of the presence of the pro-segment. We determined the optimal catalytic conditions for PbPM4 and studied enzyme kinetics on substrates and inhibitors of aspartic proteinases. Using combinatorial chemistry-based peptide libraries, we studied the active site preferences of PbPM4 at subsites S1, S2, S3, S1’, S2’ and S3’. Based on these results, we designed and synthesized a selective peptidomimetic compound and tested its inhibition of PbPM4, seven FV plasmepsins from human malaria parasites, and human cathepsin D (hcatD). We showed that this compound exhibited a >10-fold selectivity to PbPM4 and human malaria parasite plasmepsin 4 orthologs versus hcatD. Data from this study furthesr our understanding of enzymatic characteristics of the plasmepsin family and provides leads for anti-malarial drug design.
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Affiliation(s)
- Peng Liu
- Department of Biochemistry and Molecular Biology, University of Florida, College of Medicine, Gainesville, Florida, United States of America
- * E-mail: (PL); (BMD)
| | - Arthur H. Robbins
- Department of Biochemistry and Molecular Biology, University of Florida, College of Medicine, Gainesville, Florida, United States of America
| | - Melissa R. Marzahn
- Department of Biochemistry and Molecular Biology, University of Florida, College of Medicine, Gainesville, Florida, United States of America
| | - Scott H. McClung
- Protein Core, Interdisciplinary Center for Biotechnology Research, University of Florida, College of Medicine, Gainesville, Florida, United States of America
| | - Charles A. Yowell
- Department of Infectious Diseases and Pathology, University of Florida, College of Veterinary Medicine, Gainesville, Florida, United States of America
| | - Stanley M. Stevens
- Protein Core, Interdisciplinary Center for Biotechnology Research, University of Florida, College of Medicine, Gainesville, Florida, United States of America
| | - John B. Dame
- Department of Infectious Diseases and Pathology, University of Florida, College of Veterinary Medicine, Gainesville, Florida, United States of America
| | - Ben M. Dunn
- Department of Biochemistry and Molecular Biology, University of Florida, College of Medicine, Gainesville, Florida, United States of America
- * E-mail: (PL); (BMD)
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14
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McGillewie L, Soliman ME. Flap flexibility amongst plasmepsins I, II, III, IV, and V: Sequence, structural, and molecular dynamics analyses. Proteins 2015; 83:1693-705. [PMID: 26146842 DOI: 10.1002/prot.24855] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2015] [Revised: 06/09/2015] [Accepted: 06/22/2015] [Indexed: 11/05/2022]
Abstract
Herein, for the first time, we comparatively report the opening and closing of apo plasmepsin I - V. Plasmepsins belong the aspartic protease family of enzymes, and are expressed during the various stages of the P. falciparum lifecycle, the species responsible for the most lethal and virulent malaria to infect humans. Plasmepsin I, II, IV and HAP degrade hemoglobin from infected red blood cells, whereas plasmepsin V transport proteins crucial to the survival of the malaria parasite across the endoplasmic reticulum. Flap-structures covering the active site of aspartic proteases (such as HIV protease) are crucial to the conformational flexibility and dynamics of the protein, and ultimately control the binding landscape. The flap-structure in plasmepsins is made up of a flip tip in the N-terminal lying perpendicular to the active site, adjacent to the flexible loop region in the C-terminal. Using molecular dynamics, we propose three parameters to better describe the opening and closing of the flap-structure in apo plasmepsins. Namely, the distance, d1, between the flap tip and the flexible region; the dihedral angle, ϕ, to account for the twisting motion; and the TriCα angle, θ1. Simulations have shown that as the flap-structure twists, the flap and flexible region move apart opening the active site, or move toward each other closing the active site. The data from our study indicate that of all the plasmepsins investigated in the present study, Plm IV and V display the highest conformational flexibility and are more dynamic structures versus Plm I, II, and HAP.
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Affiliation(s)
- Lara McGillewie
- Molecular Modelling & Drug Design Research Group, School of Health Sciences, University of KwaZulu-Natal, Westville, Durban, 4001, South Africa
| | - Mahmoud E Soliman
- Molecular Modelling & Drug Design Research Group, School of Health Sciences, University of KwaZulu-Natal, Westville, Durban, 4001, South Africa
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15
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Structural basis for plasmepsin V inhibition that blocks export of malaria proteins to human erythrocytes. Nat Struct Mol Biol 2015. [PMID: 26214367 DOI: 10.1038/nsmb.3061] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Plasmepsin V, an essential aspartyl protease of malaria parasites, has a key role in the export of effector proteins to parasite-infected erythrocytes. Consequently, it is an important drug target for the two most virulent malaria parasites of humans, Plasmodium falciparum and Plasmodium vivax. We developed a potent inhibitor of plasmepsin V, called WEHI-842, which directly mimics the Plasmodium export element (PEXEL). WEHI-842 inhibits recombinant plasmepsin V with a half-maximal inhibitory concentration of 0.2 nM, efficiently blocks protein export and inhibits parasite growth. We obtained the structure of P. vivax plasmepsin V in complex with WEHI-842 to 2.4-Å resolution, which provides an explanation for the strict requirements for substrate and inhibitor binding. The structure characterizes both a plant-like fold and a malaria-specific helix-turn-helix motif that are likely to be important in cleavage of effector substrates for export.
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16
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Foldase and inhibitor functionalities of the pepsinogen prosegment are encoded within discrete segments of the 44 residue domain. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2015; 1854:1300-6. [PMID: 26003941 DOI: 10.1016/j.bbapap.2015.05.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2015] [Revised: 05/09/2015] [Accepted: 05/13/2015] [Indexed: 11/22/2022]
Abstract
Pepsin is initially produced as the zymogen pepsinogen, containing a 44 residue prosegment (PS) domain. When folded without the PS, pepsin forms a thermodynamically stable denatured state (refolded pepsin, Rp). To guide native folding, the PS binds to Rp, stabilizes the folding transition state, and binds tightly to native pepsin (Np), thereby driving the folding equilibrium to favor the native state. It is unknown whether these functionalities of the PS are encoded within the entire sequence or within discrete segments. PS residues 1p-29p correspond to a highly conserved region in pepsin-like aspartic proteases and we hypothesized that this segment is critical to PS-catalyzed folding. This notion was tested in the present study by characterizing the ability of various truncated PS peptides to bind Rp, catalyze folding from Rp to Np, and to inhibit Np. Four PS truncations were examined, corresponding to PS residues 1p-16p (PS1-16), 1p-29p (PS1-29), 17p-44p (PS17-44) and 30p-44p (PS30-44). The three PS functionalities could be ascribed primarily to discrete regions within the highly conserved motif: 1p-16p dictated Rp binding, 17p-29p dictated Np binding/inhibition, while the entire 1p-29p dictated transition state binding/catalyzing folding. Conversely, PS30-44 played no obvious role in PS-catalyzed folding; it is hypothesized that this more variable region may serve as a linker between PS1-29 and the mature domain. The high sequence conservation of PS1-29 and its role in catalyzing pepsin folding strongly suggest that there is a conserved PS-catalyzed folding mechanism shared by pepsin-like aspartic proteases with this motif.
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17
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Boonyalai N, Sittikul P, Yuvaniyama J. Plasmodium falciparum Plasmepsin V ( Pf PMV): Insights into recombinant expression, substrate specificity and active site structure. Mol Biochem Parasitol 2015; 201:5-15. [DOI: 10.1016/j.molbiopara.2015.05.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Revised: 04/02/2015] [Accepted: 05/11/2015] [Indexed: 10/23/2022]
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