1
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Jose J, Law RHP, Leung EWW, Wai DCC, Akhlaghi H, Chandrashekaran IR, Caradoc-Davies TT, Voskoboinik I, Feutrill J, Middlemiss D, Jeevarajah D, Bashtannyk-Puhalovich T, Giddens AC, Lee TW, Jamieson SMF, Trapani JA, Whisstock JC, Spicer JA, Norton RS. Fragment-based and structure-guided discovery of perforin inhibitors. Eur J Med Chem 2023; 261:115786. [PMID: 37716187 DOI: 10.1016/j.ejmech.2023.115786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 08/24/2023] [Accepted: 08/31/2023] [Indexed: 09/18/2023]
Abstract
Perforin is a pore-forming protein whose normal function enables cytotoxic T and natural killer (NK) cells to kill virus-infected and transformed cells. Conversely, unwanted perforin activity can also result in auto-immune attack, graft rejection and aberrant responses to pathogens. Perforin is critical for the function of the granule exocytosis cell death pathway and is therefore a target for drug development. In this study, by screening a fragment library using NMR and surface plasmon resonance, we identified 4,4-diaminodiphenyl sulfone (dapsone) as a perforin ligand. We also found that dapsone has modest (mM) inhibitory activity of perforin lytic activity in a red blood cell lysis assay in vitro. Sequential modification of this lead fragment, guided by structural knowledge of the ligand binding site and binding pose, and supported by SPR and ligand-detected 19F NMR, enabled the design of nanomolar inhibitors of the cytolytic activity of intact NK cells against various tumour cell targets. Interestingly, the ligands we developed were largely inert with respect to direct perforin-mediated red blood cell lysis but were very potent in the context of perforin's action on delivering granzymes in the immune synapse, the context in which it functions physiologically. Our work indicates that a fragment-based, structure-guided drug discovery strategy can be used to identify novel ligands that bind perforin. Moreover, these molecules have superior physicochemical properties and solubility compared to previous generations of perforin ligands.
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Affiliation(s)
- Jiney Jose
- Auckland Cancer Society Research Centre, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, A New Zealand Centre for Research Excellence, Auckland, New Zealand
| | - Ruby H P Law
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC, 3800, Australia
| | - Eleanor W W Leung
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, 3052, Australia
| | - Dorothy C C Wai
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, 3052, Australia
| | - Hedieh Akhlaghi
- Cancer Immunology Program, Peter MacCallum Cancer Centre, 305 Grattan Street, Melbourne, VIC, 3000, Australia; Sir Peter MacCallum Department of Oncology, The University of Melbourne, Parkville, VIC, 3052, Australia
| | - Indu R Chandrashekaran
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, 3052, Australia; ARC Centre for Fragment-Based Design, Monash University, Parkville, VIC, 3052, Australia
| | - Tom T Caradoc-Davies
- Australian Synchrotron, 800 Blackburn Rd., Clayton, Melbourne, VIC, 3168, Australia
| | - Ilia Voskoboinik
- Cancer Immunology Program, Peter MacCallum Cancer Centre, 305 Grattan Street, Melbourne, VIC, 3000, Australia; Sir Peter MacCallum Department of Oncology, The University of Melbourne, Parkville, VIC, 3052, Australia
| | - John Feutrill
- SYNthesis med chem (Australia) Pty Ltd, Bio21 Institute, 30 Flemington Road, Parkville, VIC, 3052, Australia
| | - David Middlemiss
- XaviaPharm, Bishop's Stortford, CM23 5EX, England, United Kingdom
| | - Devadharshini Jeevarajah
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC, 3800, Australia
| | | | - Anna C Giddens
- Auckland Cancer Society Research Centre, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand
| | - Tet Woo Lee
- Auckland Cancer Society Research Centre, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand
| | - Stephen M F Jamieson
- Auckland Cancer Society Research Centre, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, A New Zealand Centre for Research Excellence, Auckland, New Zealand; Department of Pharmacology and Clinical Pharmacology, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand
| | - Joseph A Trapani
- Cancer Immunology Program, Peter MacCallum Cancer Centre, 305 Grattan Street, Melbourne, VIC, 3000, Australia; Sir Peter MacCallum Department of Oncology, The University of Melbourne, Parkville, VIC, 3052, Australia
| | - James C Whisstock
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC, 3800, Australia.
| | - Julie A Spicer
- Auckland Cancer Society Research Centre, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, A New Zealand Centre for Research Excellence, Auckland, New Zealand.
| | - Raymond S Norton
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, 3052, Australia; ARC Centre for Fragment-Based Design, Monash University, Parkville, VIC, 3052, Australia.
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2
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Synthesis of Benzothiazole Linked Triazole Conjugates and Their Evaluation Against Cholinesterase Enzymes. ChemistrySelect 2022. [DOI: 10.1002/slct.202203060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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3
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Discovery and development of 2-aminobenzimidazoles as potent antimalarials. Eur J Med Chem 2021; 221:113518. [PMID: 34058708 DOI: 10.1016/j.ejmech.2021.113518] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 04/11/2021] [Accepted: 04/22/2021] [Indexed: 11/30/2022]
Abstract
The emergence of Plasmodium falciparum resistance to frontline antimalarials, including artemisinin combination therapies, highlights the need for new molecules that act via novel mechanisms of action. Herein, we report the design, synthesis and antimalarial activity of a series of 2-aminobenzimidazoles, featuring a phenol moiety that is crucial to the pharmacophore. Two potent molecules exhibited IC50 values against P. falciparum 3D7 strain of 42 ± 4 (3c) and 43 ± 2 nM (3g), and high potency against strains resistant to chloroquine (Dd2), artemisinin (Cam3.IIC580Y) and PfATP4 inhibitors (SJ557733), while demonstrating no cytotoxicity against human cells (HEK293, IC50 > 50 μM). The most potent molecule, possessing a 4,5-dimethyl substituted phenol (3r) displayed an IC50 value of 6.4 ± 0.5 nM against P. falciparum 3D7, representing a 12-fold increase in activity from the parent molecule. The 2-aminobenzimidazoles containing a N1-substituted phenol represent a new class of molecules that have high potency in vitro against P. falciparum malaria and low cytotoxicity. They possessed attractive pharmaceutical properties, including low molecular weight, high ligand efficiency, high solubility, synthetic tractability and low in vitro clearance in human liver microsomes.
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4
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Biswas A, Raran-Kurussi S, Narayan A, Kar A, Chandra Mashurabad P, Bhattacharyya MK, Mandal K. Efficient refolding and functional characterization of PfAMA1(DI+DII) expressed in E. coli. Biochem Biophys Rep 2021; 26:100950. [PMID: 33665380 PMCID: PMC7907217 DOI: 10.1016/j.bbrep.2021.100950] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 01/18/2021] [Accepted: 02/04/2021] [Indexed: 11/30/2022] Open
Abstract
Apical membrane antigen 1 (AMA1) is a surface protein of Plasmodium sp. that plays a crucial role in forming moving junction (MJ) during the invasion of human red blood cells. The obligatory presence of AMA1 in the parasite lifecycle designates this protein as a potential vaccine candidate and an essential target for the development of novel peptide or protein therapeutics. However, due to multiple cysteine residues in the protein sequence, attaining the native fold with correct disulfide linkages during the refolding process after expression in bacteria has remained challenging for years. Although several approaches to obtain the refolded protein from bacterial expression have been reported previously, achieving high yield during refolding and proper functional validation of the expressed protein was lacking. We report here an improved method of refolding to obtain higher quantity of refolded protein. We have also validated the refolded protein's functional activity by evaluating the expressed AMA1 protein binding with a known inhibitory peptide, rhoptry neck protein 2 (RON2), using surface plasmon resonance (SPR) and isothermal titration calorimetry (ITC). A simple yet effective protocol for P. falciparum AMA1 protein expression from E. coli. Highly reproducible and scalable refolding protocol. The modified refolding method uses a step-wise dialysis technique. Functional validation of the refolded protein shown by binding with PfRON2 ectodomain using SPR and ITC.
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Affiliation(s)
- Anamika Biswas
- TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research Hyderabad, 36/p Gopanpally, Hyderabad, Telangana 500046, India
| | - Sreejith Raran-Kurussi
- TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research Hyderabad, 36/p Gopanpally, Hyderabad, Telangana 500046, India
| | - Akash Narayan
- TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research Hyderabad, 36/p Gopanpally, Hyderabad, Telangana 500046, India
| | - Abhisek Kar
- TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research Hyderabad, 36/p Gopanpally, Hyderabad, Telangana 500046, India
| | - Purna Chandra Mashurabad
- Department of Biochemistry, School of Life Sciences, University of Hyderabad, Gachibowli, Hyderabad, Telangana 500046, India
| | - Mrinal Kanti Bhattacharyya
- Department of Biochemistry, School of Life Sciences, University of Hyderabad, Gachibowli, Hyderabad, Telangana 500046, India
| | - Kalyaneswar Mandal
- TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research Hyderabad, 36/p Gopanpally, Hyderabad, Telangana 500046, India
- Corresponding author.
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5
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Akter M, Drinkwater N, Devine SM, Drew SC, Krishnarjuna B, Debono CO, Wang G, Scanlon MJ, Scammells PJ, McGowan S, MacRaild CA, Norton RS. Identification of the Binding Site of Apical Membrane Antigen 1 (AMA1) Inhibitors Using a Paramagnetic Probe. ChemMedChem 2019; 14:603-612. [PMID: 30653832 DOI: 10.1002/cmdc.201800802] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Indexed: 11/08/2022]
Abstract
Apical membrane antigen 1 (AMA1) is essential for the invasion of host cells by malaria parasites. Several small-molecule ligands have been shown to bind to a conserved hydrophobic cleft in Plasmodium falciparum AMA1. However, a lack of detailed structural information on the binding pose of these molecules has hindered their further optimisation as inhibitors. We have developed a spin-labelled peptide based on RON2, the native binding partner of AMA1, to probe the binding sites of compounds on PfAMA1. The crystal structure of this peptide bound to PfAMA1 shows that it binds at one end of the hydrophobic groove, leaving much of the binding site unoccupied and allowing fragment hits to bind without interference. In paramagnetic relaxation enhancement (PRE)-based NMR screening, the 1 H relaxation rates of compounds binding close to the probe were enhanced. Compounds experienced different degrees of PRE as a result of their different orientations relative to the spin label while bound to AMA1. Thus, PRE-derived distance constraints can be used to identify binding sites and guide further hit optimisation.
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Affiliation(s)
- Mansura Akter
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, 3052, Australia
| | - Nyssa Drinkwater
- Biomedicine Discovery Institute, Department of Microbiology, Monash University, Wellington Road, Clayton, Victoria, 3800, Australia
| | - Shane M Devine
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, 3052, Australia
| | - Simon C Drew
- Department of Medicine (Royal Melbourne Hospital), The University of Melbourne, Melbourne, Victoria, 3010, Australia
| | - Bankala Krishnarjuna
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, 3052, Australia
| | - Cael O Debono
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, 3052, Australia
| | - Geqing Wang
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, 3052, Australia
| | - Martin J Scanlon
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, 3052, Australia
| | - Peter J Scammells
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, 3052, Australia
| | - Sheena McGowan
- Biomedicine Discovery Institute, Department of Microbiology, Monash University, Wellington Road, Clayton, Victoria, 3800, Australia
| | - Christopher A MacRaild
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, 3052, Australia
| | - Raymond S Norton
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, 3052, Australia
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6
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X-ray crystal structure of plasmin with tranexamic acid-derived active site inhibitors. Blood Adv 2017; 1:766-771. [PMID: 29296720 DOI: 10.1182/bloodadvances.2016004150] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2016] [Accepted: 04/09/2017] [Indexed: 01/09/2023] Open
Abstract
The zymogen protease plasminogen and its active form plasmin perform key roles in blood clot dissolution, tissue remodeling, cell migration, and bacterial pathogenesis. Dysregulation of the plasminogen/plasmin system results in life-threatening hemorrhagic disorders or thrombotic vascular occlusion. Accordingly, inhibitors of this system are clinically important. Currently, tranexamic acid (TXA), a molecule that prevents plasminogen activation through blocking recruitment to target substrates, is the most widely used inhibitor for the plasminogen/plasmin system in therapeutics. However, TXA lacks efficacy on the active form of plasmin. Thus, there is a need to develop specific inhibitors that target the protease active site. Here we report the crystal structures of plasmin in complex with the novel YO (trans-4-aminomethylcyclohexanecarbonyl-l-tyrosine-n-octylamide) class of small molecule inhibitors. We found that these inhibitors form key interactions with the S1 and S3' subsites of the catalytic cleft. Here, the TXA moiety of the YO compounds inserts into the primary (S1) specificity pocket, suggesting that TXA itself may function as a weak plasmin inhibitor, a hypothesis supported by subsequent biochemical and biophysical analyses. Mutational studies reveal that F587 of the S' subsite plays a key role in mediating the inhibitor interaction. Taken together, these data provide a foundation for the future development of small molecule inhibitors to specifically regulate plasmin function in a range of diseases and disorders.
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7
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Devine SM, MacRaild CA, Norton RS, Scammells PJ. Antimalarial drug discovery targeting apical membrane antigen 1. MEDCHEMCOMM 2017; 8:13-20. [PMID: 30108688 PMCID: PMC6072474 DOI: 10.1039/c6md00495d] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 10/27/2016] [Indexed: 01/06/2023]
Abstract
Malaria continues to frustrate humanity's attempts to eradicate this deadly disease. Although gains have been made over the last 15 years, drug resistance to malaria continues to be a major concern. The lack of new antimalarials with novel mechanisms of action continues to challenge the scientific community to find innovative targets to combat this persistent disease. One such target, apical membrane antigen 1 (AMA1), is an essential protein that helps the parasite invade host erythrocytes. Recently, a number of efforts have focused on the druggability of this target, aiming to block the interactions of AMA1 that mediate invasion of host cells. This review covers recent progress in drug discovery targeting this crucial protein-protein interaction in malaria.
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Affiliation(s)
- Shane M Devine
- Medicinal Chemistry , Monash Institute of Pharmaceutical Sciences , Monash University , Parkville , VIC 3052 , Australia . ;
| | - Christopher A MacRaild
- Medicinal Chemistry , Monash Institute of Pharmaceutical Sciences , Monash University , Parkville , VIC 3052 , Australia . ;
| | - Raymond S Norton
- Medicinal Chemistry , Monash Institute of Pharmaceutical Sciences , Monash University , Parkville , VIC 3052 , Australia . ;
| | - Peter J Scammells
- Medicinal Chemistry , Monash Institute of Pharmaceutical Sciences , Monash University , Parkville , VIC 3052 , Australia . ;
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8
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Norton RS, Leung EWW, Chandrashekaran IR, MacRaild CA. Applications of (19)F-NMR in Fragment-Based Drug Discovery. Molecules 2016; 21:molecules21070860. [PMID: 27438818 PMCID: PMC6273323 DOI: 10.3390/molecules21070860] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Revised: 06/21/2016] [Accepted: 06/21/2016] [Indexed: 11/16/2022] Open
Abstract
(19)F-NMR has proved to be a valuable tool in fragment-based drug discovery. Its applications include screening libraries of fluorinated fragments, assessing competition among elaborated fragments and identifying the binding poses of promising hits. By observing fluorine in both the ligand and the target protein, useful information can be obtained on not only the binding pose but also the dynamics of ligand-protein interactions. These applications of (19)F-NMR will be illustrated in this review with studies from our fragment-based drug discovery campaigns against protein targets in parasitic and infectious diseases.
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Affiliation(s)
- Raymond S Norton
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Australia.
| | - Eleanor W W Leung
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Australia.
| | - Indu R Chandrashekaran
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Australia.
| | - Christopher A MacRaild
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Australia.
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9
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Gee CT, Arntson KE, Urick AK, Mishra NK, Hawk LML, Wisniewski AJ, Pomerantz WCK. Protein-observed (19)F-NMR for fragment screening, affinity quantification and druggability assessment. Nat Protoc 2016; 11:1414-27. [PMID: 27414758 DOI: 10.1038/nprot.2016.079] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
NMR spectroscopy can be used to quantify the binding affinity between proteins and low-complexity molecules, termed 'fragments'; this versatile screening approach allows researchers to assess the druggability of new protein targets. Protein-observed (19)F-NMR (PrOF NMR) using (19)F-labeled amino acids generates relatively simple spectra that are able to provide dynamic structural information toward understanding protein folding and function. Changes in these spectra upon the addition of fragment molecules can be observed and quantified. This protocol describes the sequence-selective labeling of three proteins (the first bromodomains of Brd4 and BrdT, and the KIX domain of the CREB-binding protein) using commercially available fluorinated aromatic amino acids and fluorinated precursors as example applications of the method developed by our research group. Fragment-screening approaches are discussed, as well as Kd determination, ligand-efficiency calculations and druggability assessment, i.e., the ability to target these proteins using small-molecule ligands. Experiment times on the order of a few minutes and the simplicity of the NMR spectra obtained make this approach well-suited to the investigation of small- to medium-sized proteins, as well as the screening of multiple proteins in the same experiment.
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Affiliation(s)
- Clifford T Gee
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota, USA
| | - Keith E Arntson
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota, USA
| | - Andrew K Urick
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota, USA
| | - Neeraj K Mishra
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota, USA
| | - Laura M L Hawk
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota, USA
| | - Andrea J Wisniewski
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, Minnesota, USA
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10
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Krishnarjuna B, Lim SS, Devine SM, Debono CO, Lam R, Chandrashekaran IR, Jaipuria G, Yagi H, Atreya HS, Scanlon MJ, MacRaild CA, Scammells PJ, Norton RS. Solution NMR characterization of apical membrane antigen 1 and small molecule interactions as a basis for designing new antimalarials. J Mol Recognit 2016; 29:281-91. [DOI: 10.1002/jmr.2529] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 11/28/2015] [Indexed: 01/12/2023]
Affiliation(s)
- Bankala Krishnarjuna
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences; Monash University; 381 Royal Parade Parkville Victoria 3052 Australia
| | - San Sui Lim
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences; Monash University; 381 Royal Parade Parkville Victoria 3052 Australia
| | - Shane M. Devine
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences; Monash University; 381 Royal Parade Parkville Victoria 3052 Australia
| | - Cael O. Debono
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences; Monash University; 381 Royal Parade Parkville Victoria 3052 Australia
| | - Raymond Lam
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences; Monash University; 381 Royal Parade Parkville Victoria 3052 Australia
| | - Indu R. Chandrashekaran
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences; Monash University; 381 Royal Parade Parkville Victoria 3052 Australia
| | - Garima Jaipuria
- NMR Research Centre; Indian Institute of Science; Bangalore 560012 India
| | - Hiromasa Yagi
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences; Monash University; 381 Royal Parade Parkville Victoria 3052 Australia
| | | | - Martin J. Scanlon
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences; Monash University; 381 Royal Parade Parkville Victoria 3052 Australia
| | - Christopher A. MacRaild
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences; Monash University; 381 Royal Parade Parkville Victoria 3052 Australia
| | - Peter J. Scammells
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences; Monash University; 381 Royal Parade Parkville Victoria 3052 Australia
| | - Raymond S. Norton
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences; Monash University; 381 Royal Parade Parkville Victoria 3052 Australia
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11
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Aneja B, Kumar B, Jairajpuri MA, Abid M. A structure guided drug-discovery approach towards identification of Plasmodium inhibitors. RSC Adv 2016. [DOI: 10.1039/c5ra19673f] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
This article provides a comprehensive review of inhibitors from natural, semisynthetic or synthetic sources against key targets ofPlasmodium falciparum.
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Affiliation(s)
- Babita Aneja
- Medicinal Chemistry Lab
- Department of Biosciences
- Jamia Millia Islamia (A Central University)
- New Delhi 110025
- India
| | - Bhumika Kumar
- Medicinal Chemistry Lab
- Department of Biosciences
- Jamia Millia Islamia (A Central University)
- New Delhi 110025
- India
| | - Mohamad Aman Jairajpuri
- Protein Conformation and Enzymology Lab
- Department of Biosciences
- Jamia Millia Islamia (A Central University)
- New Delhi 110025
- India
| | - Mohammad Abid
- Medicinal Chemistry Lab
- Department of Biosciences
- Jamia Millia Islamia (A Central University)
- New Delhi 110025
- India
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12
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Parker ML, Boulanger MJ. An Extended Surface Loop on Toxoplasma gondii Apical Membrane Antigen 1 (AMA1) Governs Ligand Binding Selectivity. PLoS One 2015; 10:e0126206. [PMID: 25955165 PMCID: PMC4425356 DOI: 10.1371/journal.pone.0126206] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Accepted: 03/31/2015] [Indexed: 11/18/2022] Open
Abstract
Apicomplexan parasites are the causative agents of globally prevalent diseases including malaria and toxoplasmosis. These obligate intracellular pathogens have evolved a sophisticated host cell invasion strategy that relies on a parasite-host cell junction anchored by interactions between apical membrane antigens (AMAs) on the parasite surface and rhoptry neck 2 (RON2) proteins discharged from the parasite and embedded in the host cell membrane. Key to formation of the AMA1-RON2 complex is displacement of an extended surface loop on AMA1 called the DII loop. While conformational flexibility of the DII loop is required to expose the mature RON2 binding groove, a definitive role of this substructure has not been elucidated. To establish a role of the DII loop in Toxoplasma gondii AMA1, we engineered a form of the protein where the mobile portion of the loop was replaced with a short Gly-Ser linker (TgAMA1ΔDIIloop). Isothermal titration calorimetry measurements with a panel of RON2 peptides revealed an influential role for the DII loop in governing selectivity. Most notably, an Eimeria tenella RON2 (EtRON2) peptide that showed only weak binding to TgAMA1 bound with high affinity to TgAMA1ΔDIIloop. To define the molecular basis for the differential binding, we determined the crystal structure of TgAMA1ΔDIIloop in complex with the EtRON2 peptide. When analyzed in the context of existing AMA1-RON2 structures, spatially distinct anchor points in the AMA1 groove were identified that, when engaged, appear to provide the necessary traction to outcompete the DII loop. Collectively, these data support a model where the AMA1 DII loop serves as a structural gatekeeper to selectively filter out ligands otherwise capable of binding with high affinity in the AMA1 apical groove. These data also highlight the importance of considering the functional implications of the DII loop in the ongoing development of therapeutic intervention strategies targeting the AMA1-RON2 invasion complex.
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Affiliation(s)
- Michelle L. Parker
- Department of Biochemistry & Microbiology, University of Victoria, PO Box 3055 STN CSC, Victoria, BC, V8W 3P6, Canada
| | - Martin J. Boulanger
- Department of Biochemistry & Microbiology, University of Victoria, PO Box 3055 STN CSC, Victoria, BC, V8W 3P6, Canada
- * E-mail:
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13
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Devine SM, Mulcair MD, Debono CO, Leung EWW, Nissink JWM, Lim SS, Chandrashekaran IR, Vazirani M, Mohanty B, Simpson JS, Baell JB, Scammells PJ, Norton RS, Scanlon MJ. Promiscuous 2-aminothiazoles (PrATs): a frequent hitting scaffold. J Med Chem 2015; 58:1205-14. [PMID: 25559643 DOI: 10.1021/jm501402x] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
We have identified a class of molecules, known as 2-aminothiazoles (2-ATs), as frequent-hitting fragments in biophysical binding assays. This was exemplified by 4-phenylthiazol-2-amine being identified as a hit in 14/14 screens against a diverse range of protein targets, suggesting that this scaffold is a poor starting point for fragment-based drug discovery. This prompted us to analyze this scaffold in the context of an academic fragment library used for fragment-based drug discovery (FBDD) and two larger compound libraries used for high-throughput screening (HTS). This analysis revealed that such "promiscuous 2-aminothiazoles" (PrATs) behaved as frequent hitters under both FBDD and HTS settings, although the problem was more pronounced in the fragment-based studies. As 2-ATs are present in known drugs, they cannot necessarily be deemed undesirable, but the combination of their promiscuity and difficulties associated with optimizing them into a lead compound makes them, in our opinion, poor scaffolds for fragment libraries.
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Affiliation(s)
- Shane M Devine
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University , Parkville, Victoria 3052, Australia
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14
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Lim SS, Yang W, Krishnarjuna B, Kannan Sivaraman K, Chandrashekaran IR, Kass I, MacRaild CA, Devine SM, Debono CO, Anders RF, Scanlon MJ, Scammells PJ, Norton RS, McGowan S. Structure and dynamics of apical membrane antigen 1 from Plasmodium falciparum FVO. Biochemistry 2014; 53:7310-20. [PMID: 25360546 DOI: 10.1021/bi5012089] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Apical membrane antigen 1 (AMA1) interacts with RON2 to form a protein complex that plays a key role in the invasion of host cells by malaria parasites. Blocking this protein-protein interaction represents a potential route to controlling malaria and related parasitic diseases, but the polymorphic nature of AMA1 has proven to be a major challenge to vaccine-induced antibodies and peptide inhibitors exerting strain-transcending inhibitory effects. Here we present the X-ray crystal structure of AMA1 domains I and II from Plasmodium falciparum strain FVO. We compare our new structure to those of AMA1 from P. falciparum 3D7 and Plasmodium vivax. A combination of normalized B factor analysis and computational methods has been used to investigate the flexibility of the domain I loops and how this correlates with their roles in determining the strain specificity of human antibody responses and inhibitory peptides. We also investigated the domain II loop, a key region involved in inhibitor binding, by comparison of multiple AMA1 crystal structures. Collectively, these results provide valuable insights that should contribute to the design of strain-transcending agents targeting P. falciparum AMA1.
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Affiliation(s)
- San Sui Lim
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University , Parkville, Victoria 3052, Australia
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15
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Molecular insights into the interaction between Plasmodium falciparum apical membrane antigen 1 and an invasion-inhibitory peptide. PLoS One 2014; 9:e109674. [PMID: 25343578 PMCID: PMC4208761 DOI: 10.1371/journal.pone.0109674] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2014] [Accepted: 09/03/2014] [Indexed: 11/28/2022] Open
Abstract
Apical membrane antigen 1 (AMA1) of the human malaria parasite Plasmodium falciparum has been implicated in invasion of the host erythrocyte. It interacts with malarial rhoptry neck (RON) proteins in the moving junction that forms between the host cell and the invading parasite. Agents that block this interaction inhibit invasion and may serve as promising leads for anti-malarial drug development. The invasion-inhibitory peptide R1 binds to a hydrophobic cleft on AMA1, which is an attractive target site for small molecules that block parasite invasion. In this work, truncation and mutational analyses show that Phe5-Phe9, Phe12 and Arg15 in R1 are the most important residues for high affinity binding to AMA1. These residues interact with two well-defined binding hot spots on AMA1. Computational solvent mapping reveals that one of these hot spots is suitable for small molecule targeting. We also confirm that R1 in solution binds to AMA1 with 1∶1 stoichiometry and adopts a secondary structure consistent with the major form of R1 observed in the crystal structure of the complex. Our results provide a basis for designing high affinity inhibitors of the AMA1-RON2 interaction.
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16
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Harjani JR, Tang AX, Norton RS, Baell JB. A new methodology for the synthesis of 3-amino-1H-indole-2-carboxylates. Tetrahedron 2014. [DOI: 10.1016/j.tet.2014.08.036] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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17
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Ge X, MacRaild CA, Devine SM, Debono CO, Wang G, Scammells PJ, Scanlon MJ, Anders RF, Foley M, Norton RS. Ligand-Induced Conformational Change of Plasmodium falciparum AMA1 Detected Using 19F NMR. J Med Chem 2014; 57:6419-27. [DOI: 10.1021/jm500390g] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Xiaopeng Ge
- Department
of Biochemistry, La Trobe University, Melbourne 3086, Victoria, Australia
| | - Christopher A. MacRaild
- Medicinal
Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville 3052, Victoria, Australia
| | - Shane M. Devine
- Medicinal
Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville 3052, Victoria, Australia
| | - Cael O. Debono
- Medicinal
Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville 3052, Victoria, Australia
| | - Geqing Wang
- Medicinal
Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville 3052, Victoria, Australia
| | - Peter J. Scammells
- Medicinal
Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville 3052, Victoria, Australia
| | - Martin J. Scanlon
- Medicinal
Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville 3052, Victoria, Australia
| | - Robin F. Anders
- Department
of Biochemistry, La Trobe University, Melbourne 3086, Victoria, Australia
| | - Michael Foley
- Department
of Biochemistry, La Trobe University, Melbourne 3086, Victoria, Australia
| | - Raymond S. Norton
- Medicinal
Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville 3052, Victoria, Australia
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18
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Leung EWW, Yagi H, Harjani JR, Mulcair MD, Scanlon MJ, Baell JB, Norton RS. 19F NMR as a Probe of Ligand Interactions with the iNOS Binding site of SPRY Domain-Containing SOCS Box Protein 2. Chem Biol Drug Des 2014; 84:616-25. [DOI: 10.1111/cbdd.12355] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Revised: 03/12/2014] [Accepted: 04/29/2014] [Indexed: 01/17/2023]
Affiliation(s)
- Eleanor W. W. Leung
- Medicinal Chemistry; Monash Institute of Pharmaceutical Sciences; Monash University; Parkville Victoria 3052 Australia
| | - Hiromasa Yagi
- Medicinal Chemistry; Monash Institute of Pharmaceutical Sciences; Monash University; Parkville Victoria 3052 Australia
| | - Jitendra R. Harjani
- Medicinal Chemistry; Monash Institute of Pharmaceutical Sciences; Monash University; Parkville Victoria 3052 Australia
| | - Mark D. Mulcair
- Medicinal Chemistry; Monash Institute of Pharmaceutical Sciences; Monash University; Parkville Victoria 3052 Australia
| | - Martin J. Scanlon
- Medicinal Chemistry; Monash Institute of Pharmaceutical Sciences; Monash University; Parkville Victoria 3052 Australia
| | - Jonathan B. Baell
- Medicinal Chemistry; Monash Institute of Pharmaceutical Sciences; Monash University; Parkville Victoria 3052 Australia
| | - Raymond S. Norton
- Medicinal Chemistry; Monash Institute of Pharmaceutical Sciences; Monash University; Parkville Victoria 3052 Australia
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19
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Devine SM, Lim SS, Chandrashekaran IR, MacRaild CA, Drew DR, Debono CO, Lam R, Anders RF, Beeson JG, Scanlon MJ, Scammells PJ, Norton RS. A critical evaluation of pyrrolo[2,3-d]pyrimidine-4-amines as Plasmodium falciparum apical membrane antigen 1 (AMA1) inhibitors. MEDCHEMCOMM 2014. [DOI: 10.1039/c4md00090k] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Pyrrolo[2,3-d]pyrimidines are low affinity AMA1 binders that are also prone to aggregation.
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Affiliation(s)
- Shane M. Devine
- Medicinal Chemistry
- Monash Institute of Pharmaceutical Sciences
- Monash University
- Parkville, Australia
| | - San Sui Lim
- Medicinal Chemistry
- Monash Institute of Pharmaceutical Sciences
- Monash University
- Parkville, Australia
| | - Indu R. Chandrashekaran
- Medicinal Chemistry
- Monash Institute of Pharmaceutical Sciences
- Monash University
- Parkville, Australia
| | - Christopher A. MacRaild
- Medicinal Chemistry
- Monash Institute of Pharmaceutical Sciences
- Monash University
- Parkville, Australia
| | - Damien R. Drew
- Centre for Biomedical Research
- Burnet Institute
- Melbourne, Australia
| | - Cael O. Debono
- Medicinal Chemistry
- Monash Institute of Pharmaceutical Sciences
- Monash University
- Parkville, Australia
| | - Raymond Lam
- Medicinal Chemistry
- Monash Institute of Pharmaceutical Sciences
- Monash University
- Parkville, Australia
| | - Robin F. Anders
- Department of Biochemistry
- La Trobe University
- Melbourne, Australia
| | - James G. Beeson
- Centre for Biomedical Research
- Burnet Institute
- Melbourne, Australia
| | - Martin J. Scanlon
- Medicinal Chemistry
- Monash Institute of Pharmaceutical Sciences
- Monash University
- Parkville, Australia
- Centre of Excellence for Coherent X-Ray Science
| | - Peter J. Scammells
- Medicinal Chemistry
- Monash Institute of Pharmaceutical Sciences
- Monash University
- Parkville, Australia
| | - Raymond S. Norton
- Medicinal Chemistry
- Monash Institute of Pharmaceutical Sciences
- Monash University
- Parkville, Australia
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20
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