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Asquith CRM, East MP, Laitinen T, Alamillo-Ferrer C, Hartikainen E, Wells CI, Axtman AD, Drewry DH, Tizzard GJ, Poso A, Willson TM, Johnson GL. Discovery and optimization of narrow spectrum inhibitors of Tousled like kinase 2 (TLK2) using quantitative structure activity relationships. Eur J Med Chem 2024; 271:116357. [PMID: 38636130 DOI: 10.1016/j.ejmech.2024.116357] [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: 12/24/2023] [Revised: 03/24/2024] [Accepted: 03/24/2024] [Indexed: 04/20/2024]
Abstract
The oxindole scaffold has been the center of several kinase drug discovery programs, some of which have led to approved medicines. A series of two oxindole matched pairs from the literature were identified where TLK2 was potently inhibited as an off-target kinase. The oxindole has long been considered a promiscuous kinase inhibitor template, but across these four specific literature oxindoles TLK2 activity was consistent, while the kinome profile was radically different ranging from narrow to broad spectrum kinome coverage. We synthesized a large series of analogues, utilizing quantitative structure-activity relationship (QSAR) analysis, water mapping of the kinase ATP binding sites, kinome profiling, and small-molecule x-ray structural analysis to optimize TLK2 inhibition and kinome selectivity. This resulted in the identification of several narrow spectrum, sub-family selective, chemical tool compounds including 128 (UNC-CA2-103) that could enable elucidation of TLK2 biology.
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Affiliation(s)
- Christopher R M Asquith
- Department of Pharmacology, School of Medicine, University of North Carolina at Chapel Hill, NC, 27599, USA; School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, 70211, Kuopio, Finland; Structural Genomics Consortium and Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA.
| | - Michael P East
- Department of Pharmacology, School of Medicine, University of North Carolina at Chapel Hill, NC, 27599, USA
| | - Tuomo Laitinen
- School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, 70211, Kuopio, Finland
| | - Carla Alamillo-Ferrer
- Structural Genomics Consortium and Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Erkka Hartikainen
- School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, 70211, Kuopio, Finland
| | - Carrow I Wells
- Structural Genomics Consortium and Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Alison D Axtman
- Structural Genomics Consortium and Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - David H Drewry
- Structural Genomics Consortium and Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA; Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Graham J Tizzard
- UK National Crystallography Service, School of Chemistry, University of Southampton, Highfield Campus, Southampton, SO17 1BJ, UK
| | - Antti Poso
- School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, 70211, Kuopio, Finland
| | - Timothy M Willson
- Structural Genomics Consortium and Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Gary L Johnson
- Department of Pharmacology, School of Medicine, University of North Carolina at Chapel Hill, NC, 27599, USA; Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA.
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2
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Asquith CRM, East MP, Laitinen T, Alamillo-Ferrer C, Hartikainen E, Wells CI, Axtman AD, Drewry DH, Tizzard GJ, Poso A, Willson TM, Johnson GL. Discovery and Optimization of Narrow Spectrum Inhibitors of Tousled Like Kinase 2 (TLK2) Using Quantitative Structure Activity Relationships. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.28.573261. [PMID: 38234837 PMCID: PMC10793458 DOI: 10.1101/2023.12.28.573261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2024]
Abstract
The oxindole scaffold has been the center of several kinase drug discovery programs, some of which have led to approved medicines. A series of two oxindole matched pairs from the literature were identified where TLK2 was a potent off-target kinase. The oxindole has long been considered a promiscuous inhibitor template, but across these 4 specific literature oxindoles TLK2 activity was consistent, while the kinome profile was radically different from narrow to broad spectrum coverage. We synthesized a large series of analogues and through quantitative structure-activity relationship (QSAR) analysis, water mapping of the kinase ATP binding sites, small-molecule x-ray structural analysis and kinome profiling, narrow spectrum, sub-family selective, chemical tool compounds were identified to enable elucidation of TLK2 biology.
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Affiliation(s)
- Christopher R M Asquith
- Department of Pharmacology, School of Medicine, University of North Carolina at Chapel Hill, NC 27599, USA
- School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, 70211, Kuopio, Finland
- Structural Genomics Consortium and Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Michael P East
- Department of Pharmacology, School of Medicine, University of North Carolina at Chapel Hill, NC 27599, USA
| | - Tuomo Laitinen
- School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, 70211, Kuopio, Finland
| | - Carla Alamillo-Ferrer
- Structural Genomics Consortium and Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Erkka Hartikainen
- School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, 70211, Kuopio, Finland
| | - Carrow I Wells
- Structural Genomics Consortium and Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Alison D Axtman
- Structural Genomics Consortium and Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - David H Drewry
- Structural Genomics Consortium and Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Graham J Tizzard
- UK National Crystallography Service, School of Chemistry, University of Southampton, Highfield Campus, Southampton, SO17 1BJ, UK
| | - Antti Poso
- School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, 70211, Kuopio, Finland
| | - Timothy M Willson
- Structural Genomics Consortium and Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Gary L Johnson
- Department of Pharmacology, School of Medicine, University of North Carolina at Chapel Hill, NC 27599, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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López-Alled CM, Park SJ, Lee DJ, Murfin LC, Kociok-Köhn G, Hann JL, Wenk J, James TD, Kim HM, Lewis SE. Azulene-based fluorescent chemosensor for adenosine diphosphate. Chem Commun (Camb) 2021; 57:10608-10611. [PMID: 34570136 DOI: 10.1039/d1cc04122c] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
AzuFluor® 435-DPA-Zn, an azulene fluorophore bearing two zinc(II)-dipicolylamine receptor motifs, exhibits fluorescence enhancement in the presence of adenosine diphosphate. Selectivity for ADP over ATP, AMP and PPi results from appropriate positioning of the receptor motifs, since an isomeric sensor cannot discriminate between ADP and ATP.
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Affiliation(s)
- Carlos M López-Alled
- Department of Chemistry, University of Bath, Bath, BA2 7AY, UK. .,Centre for Sustainable Circular Technologies, University of Bath, Bath, BA2 7AY, UK.
| | - Sang Jun Park
- Department of Energy Systems Research, Ajou University, Suwon 443-749, South Korea.
| | - Dong Joon Lee
- Department of Energy Systems Research, Ajou University, Suwon 443-749, South Korea.
| | - Lloyd C Murfin
- Department of Chemistry, University of Bath, Bath, BA2 7AY, UK.
| | - Gabriele Kociok-Köhn
- Material and Chemical Characterisation Facility (MC2), University of Bath, Bath, BA2 7AY, UK
| | - Jodie L Hann
- Department of Chemistry, University of Bath, Bath, BA2 7AY, UK.
| | - Jannis Wenk
- Centre for Sustainable Circular Technologies, University of Bath, Bath, BA2 7AY, UK. .,Department of Chemical Engineering, University of Bath, Bath, BA2 7AY, UK
| | - Tony D James
- Department of Chemistry, University of Bath, Bath, BA2 7AY, UK. .,Centre for Sustainable Circular Technologies, University of Bath, Bath, BA2 7AY, UK. .,School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang 453007, China
| | - Hwan Myung Kim
- Department of Energy Systems Research, Ajou University, Suwon 443-749, South Korea.
| | - Simon E Lewis
- Department of Chemistry, University of Bath, Bath, BA2 7AY, UK. .,Centre for Sustainable Circular Technologies, University of Bath, Bath, BA2 7AY, UK.
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Hendrickson OD, Taranova NA, Zherdev AV, Dzantiev BB, Eremin SA. Fluorescence Polarization-Based Bioassays: New Horizons. SENSORS (BASEL, SWITZERLAND) 2020; 20:E7132. [PMID: 33322750 PMCID: PMC7764623 DOI: 10.3390/s20247132] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/14/2020] [Revised: 12/07/2020] [Accepted: 12/09/2020] [Indexed: 02/06/2023]
Abstract
Fluorescence polarization holds considerable promise for bioanalytical systems because it allows the detection of selective interactions in real time and a choice of fluorophores, the detection of which the biosample matrix does not influence; thus, their choice simplifies and accelerates the preparation of samples. For decades, these possibilities were successfully applied in fluorescence polarization immunoassays based on differences in the polarization of fluorophore emissions excited by plane-polarized light, whether in a free state or as part of an immune complex. However, the results of recent studies demonstrate the efficacy of fluorescence polarization as a detected signal in many bioanalytical methods. This review summarizes and comparatively characterizes these developments. It considers the integration of fluorescence polarization with the use of alternative receptor molecules and various fluorophores; different schemes for the formation of detectable complexes and the amplification of the signals generated by them. New techniques for the detection of metal ions, nucleic acids, and enzymatic reactions based on fluorescence polarization are also considered.
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Affiliation(s)
- Olga D. Hendrickson
- A.N. Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences, 119071 Moscow, Russia; (O.D.H.); (N.A.T.); (B.B.D.); (S.A.E.)
| | - Nadezhda A. Taranova
- A.N. Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences, 119071 Moscow, Russia; (O.D.H.); (N.A.T.); (B.B.D.); (S.A.E.)
| | - Anatoly V. Zherdev
- A.N. Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences, 119071 Moscow, Russia; (O.D.H.); (N.A.T.); (B.B.D.); (S.A.E.)
| | - Boris B. Dzantiev
- A.N. Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences, 119071 Moscow, Russia; (O.D.H.); (N.A.T.); (B.B.D.); (S.A.E.)
| | - Sergei A. Eremin
- A.N. Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences, 119071 Moscow, Russia; (O.D.H.); (N.A.T.); (B.B.D.); (S.A.E.)
- Department of Chemical Enzymology, Chemical Faculty, M.V. Lomonosov Moscow State University, 119234 Moscow, Russia
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5
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Miniaturized technologies for high-throughput drug screening enzymatic assays and diagnostics – A review. Trends Analyt Chem 2020. [DOI: 10.1016/j.trac.2020.115862] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Kumar M, Lowery R, Kumar V. High-Throughput Screening Assays for Cancer Immunotherapy Targets: Ectonucleotidases CD39 and CD73. SLAS DISCOVERY 2019; 25:320-326. [PMID: 31868071 DOI: 10.1177/2472555219893632] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Production of adenosine in the extracellular tumor microenvironment elicits strong immunosuppression and is associated with tumor progression. Thus, targeting adenosine-generating ectonucleotidases is a potential strategy to stimulate and prolong antitumor immunity. Because the reaction products of ectonucleotidases differ by a single phosphate group, selective detection in an assay format that is compatible with high-throughput screening (HTS) has been elusive. We report the development of biochemical assays capable of measuring the activity of ectonucleoside triphosphate diphosphohydrolase-1 (ENTPD1; also known as CD39) and ecto-5'-nucleotidase (CD73). Both assays leverage the Transcreener HTS Assay platform, which facilitates selective immunodetection of nucleotides with homogenous fluorescent readouts, fluorescence polarization or time-resolved fluorescence energy transfer. The Transcreener AMP2 Assay was used to measure CD39 activity, allowing detection of adenosine monophosphate (AMP) production (Z' > 0.6) with subnanomolar amounts of CD39, allowing IC50 determination for tool compounds, consistent with previously reported values. To detect the production of adenosine by CD73, the Transcreener ADP2 Assay was coupled with adenosine kinase (AK); conversion of adenosine to AMP and adenosine diphosphate (ADP) by AK allows detection with ADP2 antibody. The Transcreener AMP2 Assay was used to screen a 1280 Library of Pharmacologically Active Compounds (LOPAC) library and a 1600-compound subset of a ChemBridge diversity library for CD39 inhibitors, allowing the identification of nine and eight candidate compounds from each library, respectively. The Transcreener ADP2 Assay was used to screen 1600 compounds from the ChemBridge diversity library for CD73 inhibitors and identified 14 potential candidates. HTS-compatible assays for ectonucleotidase activity may allow identification of purinergic signaling pathway inhibitors important for tumor-specific immune responses during tumor pathogenesis.
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Affiliation(s)
| | | | - Vaishnav Kumar
- Dane County Youth Apprenticeship Program in Biotechnology, Verona Area High School, Verona, WI, USA
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Azerang P, Khalaj V, Kobarfard F, Owlia P, Sardari S, Shahidi S. Molecular Characterization of a Fungus Producing Membrane Active Metabolite and Analysis of the Produced Secondary Metabolite. IRANIAN BIOMEDICAL JOURNAL 2019; 23. [PMID: 30218995 PMCID: PMC6707112 DOI: 10.29252/.23.2.121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
BACKGROUND The majority of studies on soil Aspergillus concern the isolation and characterization of the antimicrobial compounds produced by this organism. Our previous studies indicated an isolated Aspergillus strain soil to be of interest, and this subject is further investigated here. METHODS Soil samples of various locations in Iran were collected. Extract from Aspergillus sp. culture was obtained using ethyl acetate fractionation. Antimicrobial activity testing was performed using broth microdilution assay against Escherichia coli, Candida albicans, and Staphylococcus aureus microorganisms. One metabolite PA3-d10 was isolated from these active extracts and identified using thin layer chromatography, preparative thin-layer chromatography, HPLC, 1HNMR (proton nuclear magnetic resonance), 2D NMR, and LC-MS (liquid chromatography-mass spectrometry). RESULTS According to morphological and biochemical properties as well as ITS rDNA sequencing, we identified an isolate of Aspergillus flavus. The ethyl acetate fraction of the fermentation medium containing membrane active metabolites showed antimicrobial effects against different bacterial and yeast indicator strains. One metabolite from these active extracts was finally identified. CONCLUSION Membrane active fraction produced by Aspergillus strain in this research demonstrated antimicrobial activities against bacteria and yeast strains. Therefore, this metabolite can be considered as a potential antimicrobial membrane active agent.
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Affiliation(s)
- Parisa Azerang
- Drug Design and Bioinformatics Unit, Medical Biotechnology Department, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | - Vahid Khalaj
- Medical Biotechnology Departments, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | - Farzad Kobarfard
- Department of Medicinal Chemistry, School of Pharmacy, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Parviz Owlia
- Molecular Microbiology Research Center, Faculty of Medicine, Shahed University, Tehran, Iran
| | - Soroush Sardari
- Drug Design and Bioinformatics Unit, Medical Biotechnology Department, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran;,Corresponding Author: Soroush Sardari , Drug Design and Bioinformatics Unit, Medical Biotechnology Department, Biotechnology Research Center, Pasteur Institute of Iran, Tehran 13164, Iran; E-mail:
| | - Sahar Shahidi
- Drug Design and Bioinformatics Unit, Medical Biotechnology Department, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
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St-Gallay SA, Bennett N, Critchlow SE, Curtis N, Davies G, Debreczeni J, Evans N, Hardern I, Holdgate G, Jones NP, Leach L, Maman S, McLoughlin S, Preston M, Rigoreau L, Thomas A, Turnbull AP, Walker G, Walsh J, Ward RA, Wheatley E, Winter-Holt J. A High-Throughput Screening Triage Workflow to Authenticate a Novel Series of PFKFB3 Inhibitors. SLAS DISCOVERY 2017; 23:11-22. [DOI: 10.1177/2472555217732289] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
A high-throughput screen (HTS) of human 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKFB3) resulted in several series of compounds with the potential for further optimization. Informatics was used to identify active chemotypes with lead-like profiles and remove compounds that commonly occurred as actives in other HTS screens. The activities were confirmed with IC50 measurements from two orthogonal assay technologies, and further analysis of the Hill slopes and comparison of the ratio of IC50 values at 10 times the enzyme concentration were used to identify artifact compounds. Several series of compounds were rejected as they had both high slopes and poor ratios. A small number of compounds representing the different leading series were assessed using isothermal titration calorimetry, and the X-ray crystal structure of the complex with PFKFB3 was solved. The orthogonal assay technology and isothermal calorimetry were demonstrated to be unreliable in identifying false-positive compounds in this case. Presented here is the discovery of the dihydropyrrolopyrimidinone series of compounds as active and novel inhibitors of PFKFB3, shown by X-ray crystallography to bind to the adenosine triphosphate site. The crystal structures of this series also reveal it is possible to flip the binding mode of the compounds, and the alternative orientation can be driven by a sigma-hole interaction between an aromatic chlorine atom and a backbone carbonyl oxygen. These novel inhibitors will enable studies to explore the role of PFKFB3 in driving the glycolytic phenotype of tumors.
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Affiliation(s)
| | - Neil Bennett
- AstraZeneca, Mereside, Alderley Park, Macclesfield, Cheshire, UK
| | | | - Nicola Curtis
- AstraZeneca, Mereside, Alderley Park, Macclesfield, Cheshire, UK
| | - Gareth Davies
- AstraZeneca, Mereside, Alderley Park, Macclesfield, Cheshire, UK
| | - Judit Debreczeni
- AstraZeneca, Mereside, Alderley Park, Macclesfield, Cheshire, UK
| | - Nicola Evans
- Cancer Research UK Therapeutic Discovery Laboratories, Jonas Webb Building, Babraham Research Campus, Cambridge, UK
| | - Ian Hardern
- AstraZeneca, Mereside, Alderley Park, Macclesfield, Cheshire, UK
| | - Geoff Holdgate
- AstraZeneca, Mereside, Alderley Park, Macclesfield, Cheshire, UK
| | - Neil P. Jones
- Cancer Research UK Therapeutic Discovery Laboratories, Jonas Webb Building, Babraham Research Campus, Cambridge, UK
| | - Lindsey Leach
- AstraZeneca, Mereside, Alderley Park, Macclesfield, Cheshire, UK
| | - Sarita Maman
- Cancer Research UK Therapeutic Discovery Laboratories, Jonas Webb Building, Babraham Research Campus, Cambridge, UK
| | - Sheila McLoughlin
- Cancer Research UK Therapeutic Discovery Laboratories, Jonas Webb Building, Babraham Research Campus, Cambridge, UK
| | - Marian Preston
- AstraZeneca, Mereside, Alderley Park, Macclesfield, Cheshire, UK
| | - Laurent Rigoreau
- Cancer Research UK Therapeutic Discovery Laboratories, Jonas Webb Building, Babraham Research Campus, Cambridge, UK
| | - Andrew Thomas
- AstraZeneca, Mereside, Alderley Park, Macclesfield, Cheshire, UK
| | - Andrew P. Turnbull
- Cancer Research UK Therapeutic Discovery Laboratories, Jonas Webb Building, Babraham Research Campus, Cambridge, UK
| | - Graeme Walker
- AstraZeneca, Mereside, Alderley Park, Macclesfield, Cheshire, UK
| | - Jarrod Walsh
- AstraZeneca, Mereside, Alderley Park, Macclesfield, Cheshire, UK
| | - Richard A. Ward
- AstraZeneca, Mereside, Alderley Park, Macclesfield, Cheshire, UK
| | - Ed Wheatley
- Cancer Research UK Therapeutic Discovery Laboratories, Jonas Webb Building, Babraham Research Campus, Cambridge, UK
| | - Jon Winter-Holt
- AstraZeneca, Mereside, Alderley Park, Macclesfield, Cheshire, UK
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Kim EJ. In Vitro Biochemical Assays for O-GlcNAc-Processing Enzymes. Chembiochem 2017; 18:1462-1472. [PMID: 28474822 DOI: 10.1002/cbic.201700138] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Indexed: 12/27/2022]
Abstract
O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA) are the only enzymes that regulate the dynamics of protein O-GlcNAcylation. Protein O-GlcNAcylation is an important post-translational modification (PTM) of nuclear and cytoplasmic proteins with O-linked β-N-acetyl-glucosamine (O-GlcNAc). O-GlcNAc and its enzymes are involved in a wide variety of cellular processes and are linked to the pathological progression of chronic diseases. Considering their emerging biological significance, systematic and rapid methods to determine the activities of OGT and OGA have become essential, and several chemical/biochemical methods for measuring the activities of these enzymes have been developed. This minireview mainly focuses on the various biochemical assay methods developed to date, while also providing a description of the fundamental principles underlying the monitoring of O-GlcNAc enzyme activities.
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Affiliation(s)
- Eun Ju Kim
- Department of Science Education-Chemistry Major, Daegu University, 15, Jilyang, Gyeongsan-si, GyeongBuk, 712-714, Republic of Korea
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Kumar M, Lowery RG. A High-Throughput Method for Measuring Drug Residence Time Using the Transcreener ADP Assay. SLAS DISCOVERY 2017; 22:915-922. [PMID: 28346107 DOI: 10.1177/2472555217695080] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Analysis of drug-target residence times during drug development can result in improved efficacy, increased therapeutic window, and reduced side effects. Residence time can be estimated as the reciprocal of the dissociation rate ( koff) of an inhibitor from its target. The traditional methods for measuring koff require synthesis of labeled ligands or low-throughput label-free methods. To provide an alternative that is better suited to an automated high-throughput screening (HTS) environment, we adapted a classic "jump dilution" catalytic assay method for determination of koff values for kinase inhibitor drugs. We used the Transcreener ADP2 Kinase assay as a universal, homogenous method to monitor the recovery of kinase activity as the drugs dissociated from preformed inhibitor-kinase complexes. We measured residence times for several drugs that bind the epidermal growth factor receptor (EGFR), ABL1, and Aurora kinases and found that the rank ordering of inhibitor koff values correlated with literature values determined using ligand binding assays. Moreover, very similar results were obtained using the Transcreener assay with fluorescence polarization (FP), fluorescence intensity (FI), and time-resolved Förster resonance energy transfer (TR-FRET) detection modes. This HTS-compatible, generic assay method should facilitate the use of residence time as a parameter for compound prioritization and optimization early in kinase drug discovery programs.
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Davis MI, Auld DS, Inglese J. Bioluminescence Methods for Assaying Kinases in Quantitative High-Throughput Screening (qHTS) Format Applied to Yes1 Tyrosine Kinase, Glucokinase, and PI5P4Kα Lipid Kinase. Methods Mol Biol 2016; 1360:47-58. [PMID: 26501901 DOI: 10.1007/978-1-4939-3073-9_4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Assays in which the detection of a biological phenomenon is coupled to the production of bioluminescence by luciferase have gained widespread use. As firefly luciferases (FLuc) and kinases share a common substrate (ATP), coupling of a kinase to FLuc allows for the amount of ATP remaining following a kinase reaction to be assessed by quantitating the amount of luminescence produced. Alternatively, the amount of ADP produced by the kinase reaction can be coupled to FLuc through a two-step process. This chapter describes the bioluminescent assays that were developed for three classes of kinases (lipid, protein, and metabolic kinases) and miniaturized to 1536-well format, enabling their use for quantitative high-throughput (qHTS) of small-molecule libraries.
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Affiliation(s)
- Mindy I Davis
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD, USA
| | - Douglas S Auld
- Center for Proteomic Chemistry, Novartis Institutes for Biomedical Research, Cambridge, MA, USA
| | - James Inglese
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD, USA.
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Zielinski T, Reichman M, Donover PS, Lowery RG. Development and Validation of a Universal High-Throughput UDP-Glycosyltransferase Assay with a Time-Resolved FRET Signal. Assay Drug Dev Technol 2016; 14:240-51. [PMID: 27136323 DOI: 10.1089/adt.2016.711] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Glycosyltransferase enzymes play diverse metabolic and regulatory roles by catalyzing the transfer of sugar molecules to protein, lipid, and carbohydrate acceptors, and they are increasingly of interest as therapeutic targets in a number of diseases, including metabolic disorders, cancer, and infectious diseases. The glycosyltransferases are a challenging target class from an assay development perspective because of the diversity of both donor and acceptor substrates and the lack of suitable glycan detection methods. However, many glycosyltransferases use uridine 5'-diphosphate (UDP) sugars as donor substrates, and detection of the free UDP reaction product provides a generic approach for measuring the activity of those enzymes. To exploit this approach for a broadly applicable high-throughput screening (HTS) assay for discovery of glycosyltransferase inhibitors, we developed a Transcreener(®) assay for immunodetection of UDP with a time-resolved Förster resonance energy transfer (TR-FRET) signal. We optimized the assay for detection of glycosyltransferase activity with nucleotide diphosphate (NDP) sugars at concentrations from 10 μM to 1 mM, achieving Z' values of 0.6 or higher. The assay was validated by orthogonal pooled screening with 8,000 compounds using polypeptide N-acetylgalactosaminyltransferase T3 as the target, and the hits were confirmed using an orthogonal readout. The reagents and signal were both stable for more than 8 h at room temperature, insuring robust performance in automated HTS environments. The TR-FRET-based UDP detection assay provides a broadly applicable approach for screening glycosyltransferases that use a UDP-sugar donor.
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Affiliation(s)
| | - Melvin Reichman
- 2 Lankenau Institute for Medical Research , Wynnewood, Pennsylvania
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Davis MI, Sasaki AT, Simeonov A. Method for Assaying the Lipid Kinase Phosphatidylinositol-5-phosphate 4-kinase α in Quantitative High-Throughput Screening (qHTS) Bioluminescent Format. Methods Mol Biol 2016; 1376:1-9. [PMID: 26552670 PMCID: PMC4696767 DOI: 10.1007/978-1-4939-3170-5_1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Lipid kinases are important regulators of a variety of cellular processes and their dysregulation causes diseases such as cancer and metabolic diseases. Distinct lipid kinases regulate the seven different phosphorylated forms of phosphatidylinositol (PtdIns). Some lipid kinases utilize long-chain lipid substrates that have limited solubility in aqueous solutions, which can lead to difficulties in developing a robust and miniaturizable biochemical assay. The ability to prepare the lipid substrate and develop assays to identify modulators of lipid kinases is important and is the focus of this methods chapter. Herein, we describe a method to prepare a DMSO-based lipid mixture that enables the 1536-well screening of the lipid kinase phosphatidylinositol-5-phosphate 4-kinase α (PI5P4Kα) utilizing the D-myo-di16-PtIns(5)P substrate in quantitative high-throughput screening (qHTS) format using the ADP-Glo™ technology to couple the production of ADP to a bioluminescent readout.
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Affiliation(s)
- Mindy I Davis
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD, 20850, USA
| | - Atsuo T Sasaki
- Department of Internal Medicine, Division of Hematology Oncology, UC Cancer Institute, College of Medicine, University of Cincinnati, Cincinnati, OH, 45267, USA
- Department of Neurosurgery, Brain Tumor Center, UC Neuroscience Institute, College of Medicine, University of Cincinnati, Cincinnati, OH, 45267, USA
| | - Anton Simeonov
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD, 20850, USA.
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14
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Bubner P, Czabany T, Luley-Goedl C, Nidetzky B. Comparison of broad-scope assays of nucleotide sugar-dependent glycosyltransferases. Anal Biochem 2015; 490:46-51. [PMID: 26297818 DOI: 10.1016/j.ab.2015.08.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2015] [Revised: 07/31/2015] [Accepted: 08/11/2015] [Indexed: 12/23/2022]
Abstract
Glycosyltransferases (GTs) are abundant in nature and diverse in their range of substrates. Application of GTs is, however, often complicated by their narrow substrate specificity. GTs with tailored specificities are highly demanded for targeted glycosylation reactions. Engineering of such GTs is, however, restricted by lack of practical and broad-scope assays currently available. Here we present an improvement of an inexpensive and simple assay that relies on the enzymatic detection of inorganic phosphate cleaved from nucleoside phosphate products released in GT reactions. This phosphatase-coupled assay (PCA) is compared with other GT assays: a pH shift assay and a commercially available immunoassay in Escherichia coli cell-free extract (CE). Furthermore, we probe PCA with three GTs with different specificities. Our results demonstrate that PCA is a versatile and apparently general GT assay with a detection limit as low as 1 mU. The detection limit of the pH shift assay is roughly 4 times higher. The immunoassay, by contrast, detected only nucleoside diphosphates (NDPs) but had the lowest detection limit. Compared with these assays, PCA showed superior robustness and, therefore, appears to be a suitable general screening assay for nucleotide sugar-dependent GTs.
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Affiliation(s)
- Patricia Bubner
- Institute of Biotechnology and Biochemical Engineering, Graz University of Technology, A-8010 Graz, Austria
| | - Tibor Czabany
- Institute of Biotechnology and Biochemical Engineering, Graz University of Technology, A-8010 Graz, Austria
| | - Christiane Luley-Goedl
- Institute of Biotechnology and Biochemical Engineering, Graz University of Technology, A-8010 Graz, Austria; Austrian Centre of Industrial Biotechnology, A-8010 Graz, Austria
| | - Bernd Nidetzky
- Institute of Biotechnology and Biochemical Engineering, Graz University of Technology, A-8010 Graz, Austria; Austrian Centre of Industrial Biotechnology, A-8010 Graz, Austria.
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15
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Fiene A, Baqi Y, Lecka J, Sévigny J, Müller CE. Fluorescence polarization immunoassays for monitoring nucleoside triphosphate diphosphohydrolase (NTPDase) activity. Analyst 2015; 140:140-8. [DOI: 10.1039/c4an01694g] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Novel and very sensitive fluorescence polarization immunoassays (FPIA) for the screening of NTPDases have been successfully established and validated.
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Affiliation(s)
- Amelie Fiene
- PharmaCenter Bonn
- Pharmaceutical Institute
- Pharmaceutical Chemistry I
- University of Bonn
- D-53121 Bonn
| | - Younis Baqi
- PharmaCenter Bonn
- Pharmaceutical Institute
- Pharmaceutical Chemistry I
- University of Bonn
- D-53121 Bonn
| | - Joanna Lecka
- Département de microbiologie-infectiologie et d'immunologie
- Faculté de Médecine
- Université Laval
- Québec
- Canada
| | - Jean Sévigny
- Département de microbiologie-infectiologie et d'immunologie
- Faculté de Médecine
- Université Laval
- Québec
- Canada
| | - Christa E. Müller
- PharmaCenter Bonn
- Pharmaceutical Institute
- Pharmaceutical Chemistry I
- University of Bonn
- D-53121 Bonn
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16
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Fluorescence immunoassay of octachlorostyrene based on Fo¨rster resonance energy transfer between CdTe quantum dots and rhodamine B. Biosens Bioelectron 2014; 60:52-6. [DOI: 10.1016/j.bios.2014.03.056] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Revised: 03/07/2014] [Accepted: 03/26/2014] [Indexed: 11/24/2022]
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17
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Shi L, Hu P, Ren Y, Feng G. An unexpected highly selective mononuclear zinc complex for adenosine diphosphate (ADP). Chem Commun (Camb) 2014; 49:11704-6. [PMID: 24192643 DOI: 10.1039/c3cc47437b] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
A simple and readily available mononuclear zinc complex, which appends two anthracene groups, was unexpectedly found to show high selectivity for ADP with a unique increased fluorescence response in neutral aqueous solution.
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Affiliation(s)
- Lei Shi
- Key Laboratory of Pesticide and Chemical Biology of Ministry of Education, College of Chemistry, Central China Normal University, 152 Luoyu Road, Wuhan 430079, P. R. China.
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18
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Considerations for the design and reporting of enzyme assays in high-throughput screening applications. ACTA ACUST UNITED AC 2014. [DOI: 10.1016/j.pisc.2013.12.001] [Citation(s) in RCA: 141] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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19
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Jing M, Verardi R, Veglia G, Bowser MT. Development of a Sensitive Assay for SERCA Activity Using FRET Detection of ADP. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2014; 6:1468-1474. [PMID: 24729794 PMCID: PMC3982649 DOI: 10.1039/c3ay41808a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Various isoforms of sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA) regulate Ca2+ homeostatic balance in both the heart (SERCA2a) and skeletal muscle (SERCA1a). Ca2+ plays a key role in these tissues as an intracellular signal that controls contractility. Due to its key role in the contractility cycle, SERCA is emerging as a promising pharmacological target to modulate heart muscle function. SERCA function is regulated by its endogenous inhibitor phospholamban (PLN). Upon binding, PLN decreases SERCA's apparent affinity for Ca2+. Therefore the interaction between PLN and SERCA has an important role in determining both physiological and pathological conditions. Quantifying the inhibitory potency of PLN is of great importance in understanding the pathophysiology of heart muscle. Traditionally, SERCA activity assays have been performed using a PK/LDH-coupled enzyme reaction, which suffers from limited sensitivity. We have developed a new SERCA activity assay based on the direct detection of the product ADP via time resolved FRET (TR-FRET). Under optimized conditions, our assay reduced the amount of SERCA required to perform the assay 1,000-fold. Inter-day reproducibility was shown to be excellent for SERCA preparations in either detergent (C12E8) or reconstituted lipids. The inhibitory effect of PLN on SERCA measured under the low-concentration conditions of our assay allowed us to more accurately investigate the binding between PLN and SERCA. Significant inhibitory effects of PLN were observed even at mid-nanomolar concentrations significantly lower than previous Kd estimates for the SERCA-PLN complex.
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Affiliation(s)
- Meng Jing
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455
| | - Raffaello Verardi
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455
| | - Gianluigi Veglia
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455 ; Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455
| | - Michael T Bowser
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455
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20
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Grütter C, Sreeramulu S, Sessa G, Rauh D. Structural characterization of the RLCK family member BSK8: a pseudokinase with an unprecedented architecture. J Mol Biol 2013; 425:4455-67. [PMID: 23911552 DOI: 10.1016/j.jmb.2013.07.034] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Revised: 07/21/2013] [Accepted: 07/25/2013] [Indexed: 10/26/2022]
Abstract
Brassinosteroid signaling kinases (BSKs) are plant-specific receptor-like cytoplasmic protein kinases involved in the brassinosteroid signaling pathway. Unlike common protein kinases, they possess a naturally occurring alanine residue at the "gatekeeper" position, as well as other sequence variations. How BSKs activate downstream proteins such as BSU1, as well as the structural consequences of their unusual sequential features, was unclear. We crystallized the catalytic domain of BSK8 and solved its structure by multiple-wavelength anomalous dispersion phasing methods to a resolution of 1.5Å. In addition, a co-crystal structure of BSK8 with 5-adenylyl imidodiphosphate (AMP-PNP) revealed unusual conformational arrangements of the nucleotide phosphate groups and catalytic key motifs, typically not observed for active protein kinases. Sequential analysis and comparisons with known pseudokinase structures suggest that BSKs represent constitutively inactive protein kinases that regulate brassinosteroid signal transfer through an allosteric mechanism.
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Affiliation(s)
- Christian Grütter
- Technische Universität Dortmund Fakultät Chemie und Chemische Biologie, Otto-Hahn-Strasse 6, D-44227 Dortmund, Germany
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21
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Weitz EA, Chang JY, Rosenfield AH, Pierre VC. A selective luminescent probe for the direct time-gated detection of adenosine triphosphate. J Am Chem Soc 2012; 134:16099-102. [PMID: 22994413 DOI: 10.1021/ja304373u] [Citation(s) in RCA: 101] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
A molecular probe for the luminescent detection of adenosine nucleotides is presented. The probe, Tb-DOTAm-Phen, readily distinguishes among the three adenosine nucleotides in buffered aqueous conditions at neutral pH, a requirement for the direct monitoring of enzymatic reactions converting adenosine triphosphate (ATP) to adenosine diphosphate or adenosine monophosphate. The probe is most efficient under millimolar concentrations of ATP which are relevant to intracellular conditions. Moreover, the long luminescence lifetime of the probe readily enables time-gating experiments.
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Affiliation(s)
- Evan A Weitz
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, USA
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22
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Peterson EJR, Janzen WP, Kireev D, Singleton SF. High-throughput screening for RecA inhibitors using a transcreener adenosine 5'-O-diphosphate assay. Assay Drug Dev Technol 2011; 10:260-8. [PMID: 22192312 DOI: 10.1089/adt.2011.0409] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The activities of the bacterial RecA protein are involved in the de novo development and transmission of antibiotic resistance genes, thus allowing bacteria to overcome the metabolic stress induced by antibacterial agents. RecA is ubiquitous and highly conserved among bacteria, but has only distant homologs in human cells. Together, this evidence points to RecA as a novel and attractive antibacterial drug target. All known RecA functions require the formation of a complex formed by multiple adenosine 5'-O-triphosphate (ATP)-bound RecA monomers on single-stranded DNA. In this complex, RecA hydrolyzes ATP. Although several methods for assessing RecA's ATPase activity have been reported, these assay conditions included relatively high concentrations of enzyme and ATP and thereby restricted the RecA conformational state. Herein, we describe the validation of commercial reagents (Transcreener(®) adenosine 5'-O-diphosphate [ADP](2) fluorescence polarization assay) for the high-throughput measurement of RecA's ATPase activity with lower concentrations of ATP and RecA. Under optimized conditions, ADP detection by the Transcreener reagent provided robust and reproducible activity data (Z'=0.92). Using the Transcreener assay, we screened 113,477 small molecules against purified RecA protein. In total, 177 small molecules were identified as confirmed hits, of which 79 were characterized by IC(50) values ≤ 10 μM and 35 were active in bioassays with live bacteria. This set of compounds comprises previously unidentified scaffolds for RecA inhibition and represents tractable hit structures for efforts aimed at tuning RecA inhibitory activity in both biochemical and bacteriological assays.
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Affiliation(s)
- Eliza J R Peterson
- Department of Biochemistry and Biophysics, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7568, USA
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23
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Klink TA, Staeben M, Twesten K, Kopp AL, Kumar M, Dunn RS, Pinchard CA, Kleman-Leyer KM, Klumpp M, Lowery RG. Development and validation of a generic fluorescent methyltransferase activity assay based on the transcreener AMP/GMP assay. ACTA ACUST UNITED AC 2011; 17:59-70. [PMID: 21956169 DOI: 10.1177/1087057111421624] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Methylation is a ubiquitous covalent modification used to control the function of diverse biomolecules including hormones, neurotransmitters, xenobiotics, proteins, nucleic acids, and lipids. Histone methyltransferases (HMTs) are currently of high interest as drug targets because of their role in epigenetic regulation; however, most HMT assay methods are either not amenable to a high-throughput screening (HTS) environment or are applicable to a limited number of enzymes. The authors developed a generic methyltransferase assay method using fluorescent immunodetection of adenosine monophosphate (AMP), which is formed from the MT reaction product S-adenosylhomocysteine in a dual-enzyme coupling step. The detection range of the assay; its suitability for HTS, including stability of reagents following dispensing and after addition to reactions; and the potential for interference from drug-like molecules was investigated. In addition, the use of the assay for measuring inhibitor potencies with peptide or intact protein substrates was examined through pilot screening with selected reference enzymes including HMT G9a. By combining a novel enzymatic coupling step with the well-characterized Transcreener AMP/GMP assay, the authors have developed a robust HTS assay for HMTs that should be broadly applicable to other types of methyltransferases as well.
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24
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Wu ZL. Phosphatase-coupled universal kinase assay and kinetics for first-order-rate coupling reaction. PLoS One 2011; 6:e23172. [PMID: 21853082 PMCID: PMC3154929 DOI: 10.1371/journal.pone.0023172] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2011] [Accepted: 07/11/2011] [Indexed: 11/18/2022] Open
Abstract
Kinases use adenosine-5′-triphosphate (ATP) as the donor substrate and generate adenosine-5′-diphosphate (ADP) as a product. An ADP-based phosphatase-coupled kinase assay is described here. In this assay, CD39L2, a nucleotidase, is added into a kinase reaction to hydrolyze ADP to AMP and phosphate. The phosphate is subsequently detected using malachite green phosphate-detection reagents. As ADP hydrolysis by CD39L2 displays a first-order rate constant, relatively simple equations are derived to calculate the coupling rate and the lagging time of the coupling reaction, allowing one to obtain kinase kinetic parameters without the completion of the coupling reaction. ATP inhibition of CD39L2-catalyzed ADP hydrolysis is also determined for correction of the kinetic data. As examples, human glucokinase, P. chrysogenum APS kinase and human ERK1, kinases specific for sugar, nucleotide and protein respectively, are assayed. To assess the compatibility of the method for high-throughput assays, Z′ factors >0.5 are also obtained for the three kinases.
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Affiliation(s)
- Zhengliang L Wu
- R&D Systems Inc., Minneapolis, Minnesota, United States of America.
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25
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Kimple AJ, Bosch DE, Giguère PM, Siderovski DP. Regulators of G-protein signaling and their Gα substrates: promises and challenges in their use as drug discovery targets. Pharmacol Rev 2011; 63:728-49. [PMID: 21737532 DOI: 10.1124/pr.110.003038] [Citation(s) in RCA: 184] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Because G-protein coupled receptors (GPCRs) continue to represent excellent targets for the discovery and development of small-molecule therapeutics, it is posited that additional protein components of the signal transduction pathways emanating from activated GPCRs themselves are attractive as drug discovery targets. This review considers the drug discovery potential of two such components: members of the "regulators of G-protein signaling" (RGS protein) superfamily, as well as their substrates, the heterotrimeric G-protein α subunits. Highlighted are recent advances, stemming from mouse knockout studies and the use of "RGS-insensitivity" and fast-hydrolysis mutations to Gα, in our understanding of how RGS proteins selectively act in (patho)physiologic conditions controlled by GPCR signaling and how they act on the nucleotide cycling of heterotrimeric G-proteins in shaping the kinetics and sensitivity of GPCR signaling. Progress is documented regarding recent activities along the path to devising screening assays and chemical probes for the RGS protein target, not only in pursuits of inhibitors of RGS domain-mediated acceleration of Gα GTP hydrolysis but also to embrace the potential of finding allosteric activators of this RGS protein action. The review concludes in considering the Gα subunit itself as a drug target, as brought to focus by recent reports of activating mutations to GNAQ and GNA11 in ocular (uveal) melanoma. We consider the likelihood of several strategies for antagonizing the function of these oncogene alleles and their gene products, including the use of RGS proteins with Gα(q) selectivity.
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Affiliation(s)
- Adam J Kimple
- Department of Pharmacology, UNC Neuroscience Center, UNC School of Medicine, University of North Carolina at Chapel Hill, 120 Mason Farm Road, Suite 4010, Chapel Hill, NC 27599-7365, USA
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Shapiro AB, Hajec L, Gao N. High-throughput, homogeneous, fluorescence intensity-based measurement of adenosine diphosphate and other ribonucleoside diphosphates with nanomolar sensitivity. Anal Biochem 2011; 415:190-6. [PMID: 21570943 DOI: 10.1016/j.ab.2011.04.027] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2011] [Revised: 04/15/2011] [Accepted: 04/18/2011] [Indexed: 10/18/2022]
Abstract
A new, homogeneous, high-throughput-compatible assay method is described for the fluorescence-based quantitation of nanomolar concentrations of ribonucleoside diphosphates (rNDPs). The principle of the method is the conversion of the rNDPs to RNA by the enzyme polynucleotide phosphorylase (EC 2.7.7.8) and detection of the RNA by the increased fluorescence of a commercial nucleic acid detection dye. A commercial RNA homopolymer complementary to the RNA product is included to increase the sensitivity for ADP and UDP. Standard curves for nanomolar concentrations of ADP, UDP, GDP, and CDP are shown. The assay detected 75 nM ADP produced by the pyruvate kinase-catalyzed phosphorylation of pyruvate with a signal-to-baseline ratio of 2.8. The assay may be used in either a continuous or a discontinuous mode.
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Affiliation(s)
- Adam B Shapiro
- Bioscience Department, Infection Innovative Medicines, AstraZeneca R&D Boston, Waltham, MA 02451, USA.
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27
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Soikkeli A, Kurkela M, Hirvonen J, Yliperttula M, Finel M. Fluorescence-based high-throughput screening assay for drug interactions with UGT1A6. Assay Drug Dev Technol 2011; 9:496-502. [PMID: 21438674 DOI: 10.1089/adt.2010.0349] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The increasing awareness and the rising importance of UDP-glucuronosyltransferases (UGTs) in the pharmacokinetics of drugs have evoked a need to develop more powerful tools for studying the role of UGTs in the metabolism of drug candidates. To this end, we have developed a fluorescent high-throughput screening assay for screening potential inhibitors and/or substrates for recombinant human UGTs-here, for the UGT1A6. The assay is based on the increase in fluorescence intensity when 1-naphthol is glucuronidated. The formation of the highly fluorescent product, 1-naphthylglucuronide, is followed at excitation wavelengths of 295 and 300 nm with fixed emission (335 nm) in real time directly from the reaction mixture. A probe concentration of 5 μM with 2.5 μg of total protein in phosphate buffer at pH 7.4 with 5% dimethyl sulfoxide resulted in optimal linearity and acceptable signal separation (signal-to-base, 3.0) for the probe reaction. The interactions of test compounds with the enzyme are detected as lower rate of 1-naphthylglucuronide formation and thus lower rate of fluorescence increase. The success of the assay was first demonstrated with the known UGT1A6 substrates 4-hydroxyindole and scopoletin (Z' factor ≥0.5) and later with nonsteroidal anti-inflammatory drugs and salicylate derivatives. Diclofenac, 5-methylsalicylic acid, 5-bromosalicylic acid, 5-chlorosalicylic acid, and 5-fluorosalicylic acid decreased the probe glucuronidation rate at 500 μM by >50%. Further, the results gained with the high-throughput screening assay correlated well with the results obtained, in parallel, with the reference high-performance liquid chromatography method.
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Affiliation(s)
- Anne Soikkeli
- Division of Pharmaceutical Technology, University of Helsinki,Viikinkaari 5E, Helsinki, Finland.
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28
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Ghadiali JE, Lowe SB, Stevens MM. Quantum-Dot-Based FRET Detection of Histone Acetyltransferase Activity. Angew Chem Int Ed Engl 2011. [DOI: 10.1002/ange.201008263] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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29
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Ghadiali JE, Lowe SB, Stevens MM. Quantum-Dot-Based FRET Detection of Histone Acetyltransferase Activity. Angew Chem Int Ed Engl 2011; 50:3417-20. [DOI: 10.1002/anie.201008263] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2010] [Indexed: 12/24/2022]
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Abstract
Quantification of the associations between biomolecules is required both to predict and understand the interactions that underpin all biological activity. Fluorescence polarization (FP) provides a nondisruptive means of measuring the association of a fluorescent ligand with a larger molecule. We describe an FP assay in which binding of fluorescein-labeled inositol 1,4,5-trisphosphate (IP(3)) to N-terminal fragments of IP(3) receptors can be characterized at different temperatures and in competition with other ligands. The assay allows the standard Gibbs free energy (ΔG°), enthalpy (ΔH°) and entropy (ΔS°) changes of ligand binding to be determined. The method is applicable to any purified ligand-binding site for which an appropriate fluorescent ligand is available. FP can be used to measure low-affinity interactions in real time without the use of radioactive materials, it is nondestructive and, with appropriate care, it can resolve ΔH° and ΔS°. The first part of the protocol, protein preparation, may take several weeks, whereas the FP measurements, once they have been optimized, would normally take 1-6 h.
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Affiliation(s)
- Ana M Rossi
- Department of Pharmacology, University of Cambridge, Cambridge, UK
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31
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Abstract
IMPORTANCE OF THE FIELD Fluorescence polarization (FP) is a homogeneous method that allows rapid and quantitative analysis of diverse molecular interactions and enzyme activities. This technique has been widely utilized in clinical and biomedical settings, including the diagnosis of certain diseases and monitoring therapeutic drug levels in body fluids. Recent developments in the field have been symbolized by the facile adoption of FP in high-throughput screening and small molecule drug discovery of an increasing range of target classes. AREAS COVERED IN THIS REVIEW The article provides a brief overview of the theoretical foundation of FP, followed by updates on recent advancements in its application for various drug target classes, including GPCRs, enzymes and protein-protein interactions. The strengths and weaknesses of this method, practical considerations in assay design, novel applications and future directions are also discussed. WHAT THE READER WILL GAIN The reader is informed of the most recent advancements and future directions of FP application to small molecule screening. TAKE HOME MESSAGE In addition to its continued utilization in high-throughput screening, FP has expanded into new disease and target areas and has been marked by increased use of labeled small molecule ligands for receptor-binding studies.
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Affiliation(s)
- Wendy A. Lea
- NIH Chemical Genomics Center, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892-3370, U.S.A
| | - Anton Simeonov
- NIH Chemical Genomics Center, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892-3370, U.S.A
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Staeben M, Kleman-Leyer KM, Kopp AL, Westermeyer TA, Lowery RG. Development and validation of a transcreener assay for detection of AMP- and GMP-producing enzymes. Assay Drug Dev Technol 2010; 8:344-55. [PMID: 20158441 DOI: 10.1089/adt.2009.0254] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Screening of AMP- and GMP-producing enzymes such as phosphodiesterases (PDEs), ligases, and synthetases would be simplified by the ability to directly detect unmodified nucleoside monophosphates. To address this need, we developed polyclonal and monoclonal antibodies that recognize AMP and GMP with nanomolar sensitivity and high selectivity vs. the corresponding triphosphate and 3',5'-cyclic monophosphate nucleotides that serve as substrates for many enzymes in these classes. One of these antibodies was used to develop a Transcreener AMP/GMP assay with a far red fluorescence polarization (FP) readout. This polyclonal antibody exhibited extremely high selectivity, with IC(50) ratios of 6,000 for ATP/AMP, 3,810 for cAMP/AMP, and 6,970 for cGMP/GMP. Standard curves mimicking enzymatic conversion of cAMP, cGMP, and ATP to the corresponding monophosphates yielded Z' values of >0.85 at 10% conversion. The assay reagents were shown to be stable for 24 h at room temperature, both before and after dispensing. The Transcreener AMP/GMP FP assay was used for enzymatic detection of cGMP- and cAMP-dependent PDEs 4A1A, 3A, and 9A2 and ATP-dependent ligases, acetyl CoA synthetase, and ubiquitin- activating enzyme (UBE1). Shifts of >100 mP were observed in the linear part of the progress curves for all enzymes tested, and the PDE isoforms exhibited the expected substrate and inhibitor selectivity. These studies demonstrate that direct immunodetection of AMP and GMP is a flexible, robust enzyme assay method for diverse AMP- and GMP-producing enzymes. Moreover, it eliminates many of the shortcomings of other methods including the need for fluorescently labeled substrates, the low signal:background inherent in substrate depletion assays, and the potential for interference with coupling enzymes.
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Dietrich JA, McKee AE, Keasling JD. High-throughput metabolic engineering: advances in small-molecule screening and selection. Annu Rev Biochem 2010; 79:563-90. [PMID: 20367033 DOI: 10.1146/annurev-biochem-062608-095938] [Citation(s) in RCA: 245] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Metabolic engineering for the overproduction of high-value small molecules is dependent upon techniques in directed evolution to improve production titers. The majority of small molecules targeted for overproduction are inconspicuous and cannot be readily obtained by screening. We provide a review on the development of high-throughput colorimetric, fluorescent, and growth-coupled screening techniques, enabling inconspicuous small-molecule detection. We first outline constraints on throughput imposed during the standard directed evolution workflow (library construction, transformation, and screening) and establish a screening and selection ladder on the basis of small-molecule assay throughput and sensitivity. An in-depth analysis of demonstrated screening and selection approaches for small-molecule detection is provided. Particular focus is placed on in vivo biosensor-based detection methods that reduce or eliminate in vitro assay manipulations and increase throughput. We conclude by providing our prospectus for the future, focusing on transcription factor-based detection systems as a natural microbial mode of small-molecule detection.
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Affiliation(s)
- Jeffrey A Dietrich
- UCSF-UCB Joint Graduate Group in Bioengineering, Berkeley, California 94720, USA.
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Hackney DD. When is weaker better? Design of an ADP sensor with weak ADP affinity, but still selective against ATP. ACS Chem Biol 2010; 5:353-4. [PMID: 20394442 DOI: 10.1021/cb1000839] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
A simple ADP biosensor would be of broad usefulness in monitoring the large number of metabolic processes that produce ADP. Several new systems have been recently described including one in the current issue of ACS Chemical Biology that provides a simple readout of the ADP concentration without significant interference by ATP.
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Affiliation(s)
- David D. Hackney
- Department of Biological Sciences, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213
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Kunzelmann S, Webb MR. A fluorescent, reagentless biosensor for ADP based on tetramethylrhodamine-labeled ParM. ACS Chem Biol 2010; 5:415-25. [PMID: 20158267 PMCID: PMC2855616 DOI: 10.1021/cb9003173] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
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Fluorescence assays for ADP detection are of considerable current interest, both in basic research and in drug discovery, as they provide a generic method for measuring the activity of ATPases and kinases. The development of a novel fluorescent biosensor is described that is based on a tetramethylrhodamine-labeled, bacterial actin homologue, ParM. The design of the biosensor takes advantage of the large conformational change of ParM on ADP binding and the strong quenching of the tetramethylrhodamine fluorescence by stacking of the dye. ParM was labeled with two tetramethylrhodamines in close proximity, whereby the fluorophores are able to interact with each other. ADP binding alters the distance and relative orientation of the tetramethylrhodamines, which leads to a change in this stacking interaction and so in the fluorescence intensity. The final ADP biosensor shows ∼15-fold fluorescence increase in response to ADP binding. It has relatively weak affinity for ADP (Kd = 30 μM), enabling it to be used at substoichiometric concentrations relative to ADP, while reporting ADP concentration changes in a wide range around the Kd value, namely, submicromolar to tens of micromolar. The biosensor strongly discriminates against ATP (>100-fold), allowing ADP detection against a background of millimolar ATP. At 20 °C, the labeled ParM binds ADP with a rate constant of 9.5 × 104 M−1 s−1 and the complex dissociates at 2.9 s−1. Thus, the biosensor is suitable for real-time measurements, and its performance in such assays is demonstrated using a sugar kinase and a mammalian protein kinase.
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Affiliation(s)
- Simone Kunzelmann
- MRC National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, United Kingdom
| | - Martin R. Webb
- MRC National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, United Kingdom
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Tanega C, Shen M, Mott BT, Thomas CJ, MacArthur R, Inglese J, Auld DS. Comparison of bioluminescent kinase assays using substrate depletion and product formation. Assay Drug Dev Technol 2010; 7:606-14. [PMID: 20059377 DOI: 10.1089/adt.2009.0230] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Assays for ATPases have been enabled for high-throughput screening (HTS) by employing firefly luciferase to detect the remaining ATP in the assay. However, for any enzyme assay, measurement of product formation is a more sensitive assay design. Recently, technologies that allow detection of the ADP product from ATPase reactions have been described using fluorescent methods of detection. We describe here the characterization of a bioluminescent assay that employs firefly luciferase in a coupled-enzyme assay format to enable detection of ADP levels from ATPase assays (ADP-Glo, Promega Corp.). We determined the performance of the ADP-Glo assay in 1,536-well microtiter plates using the protein kinase Clk4 and a 1,352 member kinase focused combinatorial library. The ADP-Glo assay was compared to the Clk4 assay performed using a bioluminescence ATP-depletion format (Kinase-Glo, Promega Corp). We performed this analysis using quantitative HTS (qHTS) where we determined potency values for all library members and identified approximately 300 compounds with potencies ranging from as low as 50 nM to >10 microM, yielding a robust dataset for the comparison. Both assay formats showed high performance (Z'-factors approximately 0.9) and showed a similar potency distribution for the actives. We conclude that the bioluminescence ADP detection assay system is a viable generic alternative to the widely used ATP-depletion assay for ATPases and discuss the advantages and disadvantages of both approaches.
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Affiliation(s)
- Cordelle Tanega
- NIH Chemical Genomics Center, National Institutes of Health, Bethesda, Maryland, USA
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Zielinski T, Kimple AJ, Hutsell SQ, Koeff MD, Siderovski DP, Lowery RG. Two Galpha(i1) rate-modifying mutations act in concert to allow receptor-independent, steady-state measurements of RGS protein activity. ACTA ACUST UNITED AC 2010; 14:1195-206. [PMID: 19820068 DOI: 10.1177/1087057109347473] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
RGS proteins are critical modulators of G-protein-coupled receptor (GPCR) signaling given their ability to deactivate Galpha subunits via GTPase-accelerating protein (GAP) activity. Their selectivity for specific GPCRs makes them attractive therapeutic targets. However, measuring GAP activity is complicated by slow guanosine diphosphate (GDP) release from Galpha and lack of solution phase assays for detecting free GDP in the presence of excess guanosine triphosphate (GTP). To overcome these hurdles, the authors developed a Galpha(i1) mutant with increased GDP dissociation and decreased GTP hydrolysis rates, enabling detection of GAP activity using steady-state GTP hydrolysis. Galpha(i1)(R178M/A326S) GTPase activity was stimulated 6- to 12-fold by RGS proteins known to act on Galpha(i) subunits and not affected by those unable to act on Galpha(i), demonstrating that the Galpha/RGS domain interaction selectivity was not altered by mutation. The selectivity and affinity of Galpha( i1)(R178M/A326S) interaction with RGS proteins was confirmed by molecular binding studies. To enable nonradioactive, homogeneous detection of RGS protein effects on Galpha(i1)(R178M/A326S), the authors developed a Transcreener fluorescence polarization immunoassay based on a monoclonal antibody that recognizes GDP with greater than 100-fold selectivity over GTP. Combining Galpha(i1)(R178M/A326S) with a homogeneous, fluorescence-based GDP detection assay provides a facile means to explore the targeting of RGS proteins as a new approach for selective modulation of GPCR signaling.
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Rowlands M, McAndrew C, Prodromou C, Pearl L, Kalusa A, Jones K, Workman P, Aherne W. Detection of the ATPase activity of the molecular chaperones Hsp90 and Hsp72 using the TranscreenerTM ADP assay kit. ACTA ACUST UNITED AC 2010; 15:279-86. [PMID: 20147598 DOI: 10.1177/1087057109360253] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The molecular chaperone heat shock protein 90 (Hsp90) is required for the correct folding and stability of a number of client proteins that are important for the growth and maintenance of cancer cells. Heat shock protein 72 (Hsp72), a co-chaperone of Hsp90, is also emerging as an attractive cancer drug target. Both proteins bind and hydrolyze adenosine triphosphate (ATP), and ATPase activity is essential for their function. Inhibition of Hsp90 ATPase activity leads to the degradation of client proteins, resulting in cell growth inhibition and apoptosis. Several small-molecule inhibitors of the ATPase activity of Hsp90 have been described and are currently being evaluated clinically for the treatment of cancer. A number of methods for the measurement of ATPase activity have been previously used, but not all of these are ideally suited to screening cascades in drug discovery projects. The authors have evaluated the use of commercial reagents (Transcreener ADP) for the measurement of ATPase activity of both yeast and human Hsp90 (ATP K(m) approximately 500 microM) and human Hsp72 (ATP K(m) ~1 microM). The low ATPase activity of human Hsp90 and its stimulation by the co-chaperone Aha1 was measured with ease using reduced incubation times, generating robust data (Z' = 0.75). The potency of several small-molecule inhibitors of both Hsp90 and Hsp72 was determined using the Transcreener reagents and compared well to that determined using other assay formats.
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Affiliation(s)
- Martin Rowlands
- Cancer Research UK Centre for Cancer Therapeutics, The Institute of Cancer Research, Haddow Laboratories, Sutton, Surrey, United Kingdom
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Kunzelmann S, Webb MR. A biosensor for fluorescent determination of ADP with high time resolution. J Biol Chem 2009; 284:33130-8. [PMID: 19801632 PMCID: PMC2785155 DOI: 10.1074/jbc.m109.047118] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Nearly every cellular process requires the presence of ATP. This is reflected in the vast number of enzymes like kinases or ATP hydrolases, both of which cleave the terminal phosphate from ATP, thereby releasing ADP. Despite the fact that ATP hydrolysis is one of the most fundamental reactions in biological systems, there are only a few methods available for direct measurements of enzymatic-driven ATP conversion. Here we describe the development of a reagentless biosensor for ADP, the common product of all ATPases and kinases, which allows the real-time detection of ADP, produced enzymatically. The biosensor is derived from a bacterial actin homologue, ParM, as protein framework. A single fluorophore (a diethylaminocoumarin), attached to ParM at the edge of the nucleotide binding site, couples ADP binding to a >3.5-fold increase in fluorescence intensity. The labeled ParM variant has high affinity for ADP (0.46 μm) and a fast signal response, controlled by the rate of ADP binding to the sensor (0.65 μm−1s−1). Amino acids in the active site were mutated to reduce ATP affinity and achieve a >400-fold discrimination against triphosphate binding. A further mutation ensured that the final sensor did not form filaments and, as a consequence, has extremely low ATPase activity. The broad applicability of N-[2-(1-maleimidyl)ethyl]-7-diethylaminocoumarin-3-carboxamide (MDCC)-ParM as a sensitive probe for ADP is demonstrated in real-time kinetic assays on two different ATPases and a protein kinase.
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Affiliation(s)
- Simone Kunzelmann
- MRC National Institute for Medical Research, Mill Hill, London NW7 1AA, United Kingdom
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