1
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Vulpetti A, Rondeau JM, Bellance MH, Blank J, Boesch R, Boettcher A, Bornancin F, Buhr S, Connor LE, Dumelin CE, Esser O, Hediger M, Hintermann S, Hommel U, Koch E, Lapointe G, Leder L, Lehmann S, Lehr P, Meier P, Muller L, Ostermeier D, Ramage P, Schiebel-Haddad S, Smith AB, Stojanovic A, Velcicky J, Yamamoto R, Hurth K. Ligandability Assessment of IL-1β by Integrated Hit Identification Approaches. J Med Chem 2024; 67:8141-8160. [PMID: 38728572 DOI: 10.1021/acs.jmedchem.4c00240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2024]
Abstract
Human interleukin-1β (IL-1β) is a pro-inflammatory cytokine that plays a critical role in the regulation of the immune response and the development of various inflammatory diseases. In this publication, we disclose our efforts toward the discovery of IL-1β binders that interfere with IL-1β signaling. To this end, several technologies were used in parallel, including fragment-based screening (FBS), DNA-encoded library (DEL) technology, peptide discovery platform (PDP), and virtual screening. The utilization of distinct technologies resulted in the identification of new chemical entities exploiting three different sites on IL-1β, all of them also inhibiting the interaction with the IL-1R1 receptor. Moreover, we identified lysine 103 of IL-1β as a target residue suitable for the development of covalent, low-molecular-weight IL-1β antagonists.
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Affiliation(s)
- Anna Vulpetti
- Biomedical Research, Novartis, CH-4002 Basel, Switzerland
| | | | | | - Jutta Blank
- Biomedical Research, Novartis, CH-4002 Basel, Switzerland
| | - Ralf Boesch
- Biomedical Research, Novartis, CH-4002 Basel, Switzerland
| | | | | | - Sylvia Buhr
- Biomedical Research, Novartis, CH-4002 Basel, Switzerland
| | | | | | - Oliver Esser
- Biomedical Research, Novartis, CH-4002 Basel, Switzerland
| | | | | | - Ulrich Hommel
- Biomedical Research, Novartis, CH-4002 Basel, Switzerland
| | - Elke Koch
- Biomedical Research, Novartis, CH-4002 Basel, Switzerland
| | | | - Lukas Leder
- Biomedical Research, Novartis, CH-4002 Basel, Switzerland
| | - Sylvie Lehmann
- Biomedical Research, Novartis, CH-4002 Basel, Switzerland
| | - Philipp Lehr
- Biomedical Research, Novartis, CH-4002 Basel, Switzerland
| | - Peter Meier
- Biomedical Research, Novartis, CH-4002 Basel, Switzerland
| | - Lionel Muller
- Biomedical Research, Novartis, CH-4002 Basel, Switzerland
| | | | - Paul Ramage
- Biomedical Research, Novartis, CH-4002 Basel, Switzerland
| | | | | | | | - Juraj Velcicky
- Biomedical Research, Novartis, CH-4002 Basel, Switzerland
| | - Rina Yamamoto
- Biomedical Research, Novartis, CH-4002 Basel, Switzerland
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2
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Cremosnik G, Mesrouze Y, Zueger P, Furkert D, Grandjean F, Argoti D, Mermet-Meillon F, Bauer MR, Brittain S, Rogemoser P, Yang W, Giovannoni J, McGregor L, Tang J, Knapp M, Holzinger S, Buhr S, Muller L, Leder L, Xie L, Fernandez C, Nieto-Oberhuber C, Chène P, Galli GG, Sesterhenn F. mRNA Display Identifies Potent, Paralog-Selective Peptidic Ligands for ARID1B. ACS Chem Biol 2024; 19:1142-1150. [PMID: 38655884 PMCID: PMC11106749 DOI: 10.1021/acschembio.4c00083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Revised: 04/15/2024] [Accepted: 04/15/2024] [Indexed: 04/26/2024]
Abstract
The ARID1A and ARID1B subunits are mutually exclusive components of the BAF variant of SWI/SNF chromatin remodeling complexes. Loss of function mutations in ARID1A are frequently observed in various cancers, resulting in a dependency on the paralog ARID1B for cancer cell proliferation. However, ARID1B has never been targeted directly, and the high degree of sequence similarity to ARID1A poses a challenge for the development of selective binders. In this study, we used mRNA display to identify peptidic ligands that bind with nanomolar affinities to ARID1B and showed high selectivity over ARID1A. Using orthogonal biochemical, biophysical, and chemical biology tools, we demonstrate that the peptides engage two different binding pockets, one of which directly involves an ARID1B-exclusive cysteine that could allow covalent targeting by small molecules. Our findings impart the first evidence of the ligandability of ARID1B, provide valuable tools for drug discovery, and suggest opportunities for the development of selective molecules to exploit the synthetic lethal relationship between ARID1A and ARID1B in cancer.
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Affiliation(s)
- Gregor
S. Cremosnik
- Global
Discovery Chemistry, Novartis Biomedical
Research, CH-4056 Basel, Switzerland
| | - Yannick Mesrouze
- Disease
area Oncology, Novartis Biomedical Research, CH-4056 Basel, Switzerland
| | - Patrik Zueger
- Global
Discovery Chemistry, Novartis Biomedical
Research, CH-4056 Basel, Switzerland
| | - David Furkert
- Discovery
Sciences, Novartis Biomedical Research, CH-4056 Basel, Switzerland
| | - Frédéric Grandjean
- Discovery
Sciences, Novartis Biomedical Research, CH-4056 Basel, Switzerland
| | - Dayana Argoti
- Global
Discovery Chemistry, Novartis Biomedical
Research, Emeryville, California 94608, United States
| | | | - Matthias R. Bauer
- Global
Discovery Chemistry, Novartis Biomedical
Research, CH-4056 Basel, Switzerland
| | - Scott Brittain
- Discovery
Sciences, Novartis Biomedical Research, Cambridge, Massachusetts 02139, United States
| | - Phuong Rogemoser
- Discovery
Sciences, Novartis Biomedical Research, Cambridge, Massachusetts 02139, United States
| | - Winnie Yang
- Discovery
Sciences, Novartis Biomedical Research, Cambridge, Massachusetts 02139, United States
| | - Jerome Giovannoni
- Discovery
Sciences, Novartis Biomedical Research, CH-4056 Basel, Switzerland
| | - Lynn McGregor
- Discovery
Sciences, Novartis Biomedical Research, Cambridge, Massachusetts 02139, United States
| | - Jenny Tang
- Global
Discovery Chemistry, Novartis Biomedical
Research, Emeryville, California 94608, United States
| | - Mark Knapp
- Global
Discovery Chemistry, Novartis Biomedical
Research, Emeryville, California 94608, United States
| | - Sandra Holzinger
- Discovery
Sciences, Novartis Biomedical Research, CH-4056 Basel, Switzerland
| | - Sylvia Buhr
- Discovery
Sciences, Novartis Biomedical Research, CH-4056 Basel, Switzerland
| | - Lionel Muller
- Discovery
Sciences, Novartis Biomedical Research, CH-4056 Basel, Switzerland
| | - Lukas Leder
- Discovery
Sciences, Novartis Biomedical Research, CH-4056 Basel, Switzerland
| | - Lili Xie
- Discovery
Sciences, Novartis Biomedical Research, Emeryville, California 94608, United States
| | - Cesar Fernandez
- Discovery
Sciences, Novartis Biomedical Research, CH-4056 Basel, Switzerland
| | | | - Patrick Chène
- Disease
area Oncology, Novartis Biomedical Research, CH-4056 Basel, Switzerland
| | - Giorgio G. Galli
- Disease
area Oncology, Novartis Biomedical Research, CH-4056 Basel, Switzerland
| | - Fabian Sesterhenn
- Discovery
Sciences, Novartis Biomedical Research, CH-4056 Basel, Switzerland
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3
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Ottl J, Leder L, Schaefer JV, Dumelin CE. Encoded Library Technologies as Integrated Lead Finding Platforms for Drug Discovery. Molecules 2019; 24:E1629. [PMID: 31027189 PMCID: PMC6514559 DOI: 10.3390/molecules24081629] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 04/17/2019] [Accepted: 04/21/2019] [Indexed: 01/22/2023] Open
Abstract
The scope of targets investigated in pharmaceutical research is continuously moving into uncharted territory. Consequently, finding suitable chemical matter with current compound collections is proving increasingly difficult. Encoded library technologies enable the rapid exploration of large chemical space for the identification of ligands for such targets. These binders facilitate drug discovery projects both as tools for target validation, structural elucidation and assay development as well as starting points for medicinal chemistry. Novartis internalized two complementing encoded library platforms to accelerate the initiation of its drug discovery programs. For the identification of low-molecular weight ligands, we apply DNA-encoded libraries. In addition, encoded peptide libraries are employed to identify cyclic peptides. This review discusses how we apply these two platforms in our research and why we consider it beneficial to run both pipelines in-house.
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Affiliation(s)
- Johannes Ottl
- Novartis Institutes for Biomedical Research, 4056 Basel, Switzerland.
| | - Lukas Leder
- Novartis Institutes for Biomedical Research, 4056 Basel, Switzerland.
| | - Jonas V Schaefer
- Novartis Institutes for Biomedical Research, 4056 Basel, Switzerland.
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4
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Kallen J, Bergsdorf C, Arnaud B, Bernhard M, Brichet M, Cobos-Correa A, Elhajouji A, Freuler F, Galimberti I, Guibourdenche C, Haenni S, Holzinger S, Hunziker J, Izaac A, Kaufmann M, Leder L, Martus HJ, von Matt P, Polyakov V, Roethlisberger P, Roma G, Stiefl N, Uteng M, Lerchner A. X-ray Structures and Feasibility Assessment of CLK2 Inhibitors for Phelan-McDermid Syndrome. ChemMedChem 2018; 13:1997-2007. [PMID: 29985556 DOI: 10.1002/cmdc.201800344] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Indexed: 01/15/2023]
Abstract
CLK2 inhibition has been proposed as a potential mechanism to improve autism and neuronal functions in Phelan-McDermid syndrome (PMDS). Herein, the discovery of a very potent indazole CLK inhibitor series and the CLK2 X-ray structure of the most potent analogue are reported. This new indazole series was identified through a biochemical CLK2 Caliper assay screen with 30k compounds selected by an in silico approach. Novel high-resolution X-ray structures of all CLKs, including the first CLK4 X-ray structure, bound to known CLK2 inhibitor tool compounds (e.g., TG003, CX-4945), are also shown and yield insight into inhibitor selectivity in the CLK family. The efficacy of the new CLK2 inhibitors from the indazole series was demonstrated in the mouse brain slice assay, and potential safety concerns were investigated. Genotoxicity findings in the human lymphocyte micronucleus test (MNT) assay are shown by using two structurally different CLK inhibitors to reveal a major concern for pan-CLK inhibition in PMDS.
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Affiliation(s)
- Joerg Kallen
- Novartis Institutes for BioMedical Research, Novartis Campus, 4002, Basel, Switzerland
| | - Christian Bergsdorf
- Novartis Institutes for BioMedical Research, Novartis Campus, 4002, Basel, Switzerland
| | - Bertrand Arnaud
- Global Discovery Chemistry, Novartis Institutes for BioMedical Research, Novartis Campus, 4002, Basel, Switzerland
| | - Mario Bernhard
- Novartis Institutes for BioMedical Research, Novartis Campus, 4002, Basel, Switzerland
| | - Murielle Brichet
- Novartis Institutes for BioMedical Research, Novartis Campus, 4002, Basel, Switzerland
| | - Amanda Cobos-Correa
- Novartis Institutes for BioMedical Research, Novartis Campus, 4002, Basel, Switzerland
| | - Azeddine Elhajouji
- Novartis Institutes for BioMedical Research, Novartis Campus, 4002, Basel, Switzerland
| | - Felix Freuler
- Novartis Institutes for BioMedical Research, Novartis Campus, 4002, Basel, Switzerland
| | - Ivan Galimberti
- Novartis Institutes for BioMedical Research, Novartis Campus, 4002, Basel, Switzerland
| | - Christel Guibourdenche
- Global Discovery Chemistry, Novartis Institutes for BioMedical Research, Novartis Campus, 4002, Basel, Switzerland
| | - Simon Haenni
- Novartis Institutes for BioMedical Research, Novartis Campus, 4002, Basel, Switzerland
| | - Sandra Holzinger
- Novartis Institutes for BioMedical Research, Novartis Campus, 4002, Basel, Switzerland
| | - Juerg Hunziker
- Novartis Institutes for BioMedical Research, Novartis Campus, 4002, Basel, Switzerland
| | - Aude Izaac
- Novartis Institutes for BioMedical Research, Novartis Campus, 4002, Basel, Switzerland
| | - Markus Kaufmann
- Novartis Institutes for BioMedical Research, Novartis Campus, 4002, Basel, Switzerland
| | - Lukas Leder
- Novartis Institutes for BioMedical Research, Novartis Campus, 4002, Basel, Switzerland
| | - Hans-Joerg Martus
- Novartis Institutes for BioMedical Research, Novartis Campus, 4002, Basel, Switzerland
| | - Peter von Matt
- Global Discovery Chemistry, Novartis Institutes for BioMedical Research, Novartis Campus, 4002, Basel, Switzerland
| | - Valery Polyakov
- Global Discovery Chemistry, Novartis Institutes for BioMedical Research, Novartis Campus, 4002, Basel, Switzerland
| | - Patrik Roethlisberger
- Novartis Institutes for BioMedical Research, Novartis Campus, 4002, Basel, Switzerland
| | - Guglielmo Roma
- Novartis Institutes for BioMedical Research, Novartis Campus, 4002, Basel, Switzerland
| | - Nikolaus Stiefl
- Global Discovery Chemistry, Novartis Institutes for BioMedical Research, Novartis Campus, 4002, Basel, Switzerland
| | - Marianne Uteng
- Novartis Institutes for BioMedical Research, Novartis Campus, 4002, Basel, Switzerland
| | - Andreas Lerchner
- Global Discovery Chemistry, Novartis Institutes for BioMedical Research, Novartis Campus, 4002, Basel, Switzerland
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5
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Øyri L, Narverud I, Bogsrud M, Hansson P, Leder L, Byfuglien M, Veierød M, Ulven S, Holven K. Intake of sfa compared to pufa induce lower postprandial ldl receptor gene expression in pbmc in subjects with and without FH. Atherosclerosis 2018. [DOI: 10.1016/j.atherosclerosis.2018.06.498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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6
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Abstract
Chemically modified proteins play an important role in several fields of pharmaceutical R&D, starting from various activities in drug discovery all the way down to biopharmaceuticals with improved properties such as antibody-drug conjugates. In the first part of the present chapter the significance and use of labeled proteins in biophysical methods, biochemical and cellular assays, in vivo imaging, and biopharmaceuticals is reviewed in general. In this context, the most relevant methods for site-specific modification of proteins and their application are also described. In the second part of the chapter, in-house (Novartis) results and experience with different techniques for selective protein labeling are discussed, with a focus on chemical or enzymatic (Avi-tag) biotinylation of proteins and their application in biophysical and biochemical assays. It can be concluded that while modern methods of site-specific protein labeling offer new possibilities for pharmaceutical R&D, classical methods are still the mainstay mainly due to being well established. However, site-specific protein labeling is expected to increase in importance, in particular for antibody-drug conjugates and other chemically modified biopharmaceuticals.
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Affiliation(s)
- Lukas Leder
- Center for Proteomic Chemistry, Novartis Institutes for Biomedical Research, Novartis Campus, 4056, Basel, Switzerland,
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7
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Siehler S, Yamamoto R, Bergsdorf C, Leder L, Reinhardt J, Freuler F, Scheel G. Novel pharmacological insights for adenylyl cyclase 5, a gatekeeper of GPCR signaling. FASEB J 2010. [DOI: 10.1096/fasebj.24.1_supplement.lb477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Sandra Siehler
- Center for Proteomic ChemistryNovartis Institutes for BioMedical Research (NIBR)BaselSwitzerland
| | - Rina Yamamoto
- Center for Proteomic ChemistryNovartis Institutes for BioMedical Research (NIBR)BaselSwitzerland
| | - Christian Bergsdorf
- Center for Proteomic ChemistryNovartis Institutes for BioMedical Research (NIBR)BaselSwitzerland
| | - Lukas Leder
- Center for Proteomic ChemistryNovartis Institutes for BioMedical Research (NIBR)BaselSwitzerland
| | - Juergen Reinhardt
- Center for Proteomic ChemistryNovartis Institutes for BioMedical Research (NIBR)BaselSwitzerland
| | - Felix Freuler
- Center for Proteomic ChemistryNovartis Institutes for BioMedical Research (NIBR)BaselSwitzerland
| | - Guenther Scheel
- Center for Proteomic ChemistryNovartis Institutes for BioMedical Research (NIBR)BaselSwitzerland
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8
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Wanders A, Leder L, Banga J, Katan M, Brouwer I. A high intake of conjugated linoleic acid does not affect liver and kidney function tests in healthy human subjects. Food Chem Toxicol 2010; 48:587-90. [DOI: 10.1016/j.fct.2009.11.036] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2009] [Revised: 10/25/2009] [Accepted: 11/16/2009] [Indexed: 10/20/2022]
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9
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Freuler F, Stettler T, Meyerhofer M, Leder L, Mayr LM. Development of a novel Gateway-based vector system for efficient, multiparallel protein expression in Escherichia coli. Protein Expr Purif 2008; 59:232-41. [DOI: 10.1016/j.pep.2008.02.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2007] [Revised: 02/04/2008] [Accepted: 02/13/2008] [Indexed: 11/30/2022]
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10
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Abstract
The expression of high levels of stable and functional proteins remains a bottleneck in many scientific endeavors, including the determination of structures in a high-throughput fashion or the screening for novel active compounds in modern drug discovery. Recently, numerous developments have been made to improve the production of soluble and active proteins in heterologous expression systems. These include modifications to the expression constructs, the introduction of new and/or improved pro- and eukaryotic expression systems, and the development of improved cell-free protein synthesis systems. The introduction of robotics has enabled a massive parallelization of expression experiments, thereby vastly increasing the throughput and, hopefully, the output of such experiments. In addition, the big challenges of recombinant overexpression of membrane and secreted proteins are tackled, and some new methods are reviewed.
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Affiliation(s)
- Michael Forstner
- Protein Expression & Purification Novartis Institutes of BioMedical Research, Discovery Technologies/Lead Discovery Center CH-4002 Basel, Switzerland.
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11
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Leder L, Freuler F, Forstner M, Mayr LM. New methods for efficient protein production in drug discovery. Curr Opin Drug Discov Devel 2007; 10:193-202. [PMID: 17436555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
The requirement for high levels of stable and functional proteins remains a bottleneck in many processes of modern drug discovery, including the high-throughput screening for novel active compounds or the determination of protein structures. Recently, numerous developments have been made to improve the production of soluble and active proteins in heterologous expression systems. These include versatile expression vectors, new methods for quick cloning, the introduction of novel and/or improved prokaryotic and eukaryotic expression systems, and more efficient and faster chromatographic procedures that result in highly pure proteins. In addition, several techniques allow the attachment of small molecular labels to proteins in a site-specific manner, which can be highly useful for various important experimental techniques in current drug discovery.
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Affiliation(s)
- Lukas Leder
- Novartis Institutes for BioMedical Research, Center for Proteomic Chemistry, WSJ-88.6.02A, Lichtstrasse 35, CH-4056 Basel, Switzerland.
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12
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Klumpp M, Boettcher A, Becker D, Meder G, Blank J, Leder L, Forstner M, Ottl J, Mayr LM. Readout Technologies for Highly Miniaturized Kinase Assays Applicable to High-Throughput Screening in a 1536-Well Format. ACTA ACUST UNITED AC 2006; 11:617-33. [PMID: 16760365 DOI: 10.1177/1087057106288444] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
This article discusses the development of homogeneous, miniaturized assays for the identification of novel kinase inhibitors from very large compound collections. In particular, the suitability of time-resolved fluorescence resonance energy transfer (TR-RET) based on phospho-specific antibodies, an antibody-independent fluorescence polarization (FP) approach using metal-coated beads (IMAP™ technology), and the determination of adenosine triphosphate consumption through chemiluminescence is evaluated. These readouts are compared with regard to assay sensitivity, compound interference, reagent consumption, and performance in a 1536-well format, and practical considerations for their application in primary screening or in the identification of kinase substrates are discussed. All of the tested technologies were found to be suitable for miniaturized high-throughput screening (HTS) in principle, but each of them has distinct limitations and advantages. Therefore, the target-specific selection of the most appropriate readout technology is recommended to ensure maximal relevance of HTS campaigns.
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Affiliation(s)
- Martin Klumpp
- Novartis Institute for Biomedical Research, Basel, Switzerland.
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13
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Tirat A, Freuler F, Stettler T, Mayr LM, Leder L. Evaluation of two novel tag-based labelling technologies for site-specific modification of proteins. Int J Biol Macromol 2006; 39:66-76. [PMID: 16503347 DOI: 10.1016/j.ijbiomac.2006.01.012] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2005] [Revised: 01/23/2006] [Accepted: 01/23/2006] [Indexed: 11/21/2022]
Abstract
Modern drug discovery strongly depends on the availability of target proteins in sufficient amounts and with desired properties. For some applications, proteins have to be produced with specific modifications such as tags for protein purification, fluorescent or radiometric labels for detection, glycosylation and phosphorylation for biological activity, and many more. It is well known that covalent modifications can have adverse effects on the biological activity of some target proteins. It is therefore one of the major challenges in protein chemistry to generate covalent modifications without affecting the biological activity of the target protein. Current procedures for modification mostly rely on non-specific labelling of lysine or cysteine residues on the protein of interest, but alternative approaches dedicated to site-specific protein modification are being developed and might replace most of the commonly used methodologies. In this study, we investigated two novel methods where target proteins can be expressed in E. coli with a fusion partner that allows protein modification in a covalent and highly selective manner. Firstly, we explored a method based on the human DNA repair protein O6-alkylguanine-DNA alkyltransferase (hAGT) as a fusion tag for site-directed attachment of small molecules. The AGT-tag (SNAP-tag) can accept almost any chemical moiety when it is attached to the guanine base through a benzyl group. In our experiments we were able to label a target protein fused to the AGT-tag with various fluorophores coupled to O6-benzylguanine. Secondly, we tested in vivo and in vitro site-directed biotinylation with two different tags, consisting of either 15 (AviTag) or 72 amino acids (BioEase tag), which serve as a substrate for bacterial biotin ligase birA. When birA protein was co-expressed in E. coli biotin was incorporated almost completely into a model protein which carried these recognition tags at its C-terminus. The same findings were also obtained with in vitro biotinylation assays using pure birA independently over-expressed in E. coli and added to the biotinylation reaction in the test tube. For both biotinylation methods, peptide mapping and LC-MS proved the highly site-specific modification of the corresponding tags. Our results indicate that these novel site-specific labelling reactions work in a highly efficient manner, allow almost quantitative labelling of the target proteins, have no deleterious effect on the biological activity and are easy to perform in standard laboratories.
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Affiliation(s)
- Aline Tirat
- Novartis Institutes for Biomedical Research, Discovery Technologies, CH-4056 Basel, Switzerland
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14
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Tirat A, Schilb A, Riou V, Leder L, Gerhartz B, Zimmermann J, Worpenberg S, Eidhoff U, Freuler F, Stettler T, Mayr L, Ottl J, Leuenberger B, Filipuzzi I. Synthesis and characterization of fluorescent ubiquitin derivatives as highly sensitive substrates for the deubiquitinating enzymes UCH-L3 and USP-2. Anal Biochem 2005; 343:244-55. [PMID: 15963938 DOI: 10.1016/j.ab.2005.04.023] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2005] [Revised: 04/07/2005] [Accepted: 04/13/2005] [Indexed: 10/25/2022]
Abstract
Deubiquitinating enzymes (DUBs) catalyze the removal of attached ubiquitin molecules from amino groups of target proteins. The large family of DUBs plays an important role in the regulation of the intracellular homeostasis of different proteins and influences therefore key events such as cell division, apoptosis, etc. The DUB family members UCH-L3 and USP2 are believed to inhibit the degradation of various tumor-growth-promoting proteins by removing the trigger for degradation. Inhibitors of these enzymes should therefore lead to enhanced degradation of oncoproteins and may thus stop tumor growth. To develop an enzymatic assay for the search of UCH-L3 and USP2 inhibitors, C-terminally labeled ubiquitin substrates were enzymatically synthesized. We have used the ubiquitin-activating enzyme E1 and one of the ubiquitin-conjugating enzymes E2 to attach a fluorescent lysine derivative to the C terminus of ubiquitin. Since only the epsilon-NH(2) group of the lysine derivatives was free and reactive, the conjugates closely mimic the isopeptide bond between the ubiquitin and the lysine side chains of the targeted proteins. Various substrates were synthesized by this approach and characterized enzymatically with the two DUBs. The variant consisting of the fusion protein between the large N-terminal NusA tag and the ubiquitin which was modified with alpha-NH(2)-tetramethylrhodamin-lysine, was found to give the highest dynamic range in a fluorescence polarization readout. Therefore we have chosen this substrate for the development of a miniaturized, fluorescence-polarization-based high-throughput screening assay.
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Affiliation(s)
- Aline Tirat
- Discovery Technologies, Novartis Institutes for Biomedical Research, CH-4058 Basel, Switzerland
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15
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Abstract
The neural cell adhesion molecules axonin-1 and NgCAM have been genetically engineered and covalently immobilized on glass and silicon oxide surfaces in their correct orientation. Surfaces treated with these adhesion molecules were used as substrates for culturing dorsal root ganglion neurons. The cleft between the neuron cell membrane and the surface was determined using fluorescence interference contrast (FLIC) microscopy. For comparison, cell--material distances on laminin, RGDC, polylysine and amino-terminated surfaces were measured. When the neurons grow on axonin-1 the cell--surface distance is at a minimum (37 nm) probably because the glycocalyx hinders a closer contact. A selective treatment of extracellular electrodes with axonin-1 could be used to improve the cell-material contact and thus increase extracellularly recorded signals.
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Affiliation(s)
- H Sorribas
- Laboratory for Micro- and Nanotechnology, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
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16
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Freigang J, Proba K, Leder L, Diederichs K, Sonderegger P, Welte W. The crystal structure of the ligand binding module of axonin-1/TAG-1 suggests a zipper mechanism for neural cell adhesion. Cell 2000; 101:425-33. [PMID: 10830169 DOI: 10.1016/s0092-8674(00)80852-1] [Citation(s) in RCA: 132] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
We have determined the crystal structure of the ligand binding fragment of the neural cell adhesion molecule axonin-1/TAG-1 comprising the first four immunoglobulin (Ig) domains. The overall structure of axonin-1(Ig1-4) is U-shaped due to contacts between domains 1 and 4 and domains 2 and 3. In the crystals, these molecules are aligned in a string with adjacent molecules oriented in an anti-parallel fashion and their C termini perpendicular to the string. This arrangement suggests that cell adhesion by homophilic axonin-1 interaction occurs by the formation of a linear zipper-like array in which the axonin-1 molecules are alternately provided by the two apposed membranes. In accordance with this model, mutations in a loop critical for the formation of the zipper resulted in the loss of the homophilic binding capacity of axonin-1.
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Affiliation(s)
- J Freigang
- Faculty of Biology, University of Konstanz, Germany
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17
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Sorribas H, Padeste C, Mezzacasa T, Tiefenauer L, Leder L, Fitzli D, Sonderegger P. Neurite outgrowth on microstructured surfaces functionalized by a neural adhesion protein. J Mater Sci Mater Med 1999; 10:787-791. [PMID: 15347952 DOI: 10.1023/a:1008955101492] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Designed networks of neurons are potentially very useful to investigate neural activities. Using photolithography microgrooves suited in size for single neurons have been produced on glass chips. Two conducting gold lanes ending in each microgroove allow extracelluar stimulation of the neurons and recording of their activity. A cell adhesive surface was created by functionalization of glass with the adhesion peptide RGDC. In addition, in order to optimize the contact of the neuronal cell membrane to the electrode surface axonin-1, a specific neural adhesion protein was used. A recombinant form of axonin-1 was produced and immobilized in a correct orientation on protected gold surfaces through a C-terminal cysteine residue. Neurite outgrowth of neurons cultured on chips derivatized with RGDC or axonin-1 were compared. The developed materials and methods represent a first step towards establishing designed functionalized glass surfaces for neurophysiological investigations.
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Affiliation(s)
- H Sorribas
- Micro- and Nanotechnology, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
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18
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Li H, Llera A, Tsuchiya D, Leder L, Ysern X, Schlievert PM, Karjalainen K, Mariuzza RA. Three-dimensional structure of the complex between a T cell receptor beta chain and the superantigen staphylococcal enterotoxin B. Immunity 1998; 9:807-16. [PMID: 9881971 DOI: 10.1016/s1074-7613(00)80646-9] [Citation(s) in RCA: 144] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Superantigens (SAGs) are a class of immunostimulatory proteins of bacterial or viral origin that activate T cells by binding to the V beta domain of the T cell antigen receptor (TCR). The three-dimensional structure of the complex between a TCR beta chain (mouse V beta8.2) and the SAG staphylococcal enterotoxin B (SEB) at 2.4 A resolution reveals why SEB recognizes only certain V beta families, as well as why only certain SAGs bind mouse V beta8.2. Models of the TCR-SEB-peptide/MHC class II complex indicate that V alpha interacts with the MHC beta chain in the TCR-SAG-MHC complex. The extent of the interaction is variable and is largely determined by the geometry of V alpha/V beta domain association. This variability can account for the preferential expression of certain V alpha regions among T cells reactive with SEB.
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MESH Headings
- Animals
- Crystallography, X-Ray
- Enterotoxins/chemistry
- Enterotoxins/immunology
- Histocompatibility Antigens Class II/chemistry
- Histocompatibility Antigens Class II/immunology
- Mice
- Models, Molecular
- Peptide Fragments/chemistry
- Peptide Fragments/immunology
- Peptides/chemistry
- Peptides/immunology
- Protein Conformation
- Receptors, Antigen, T-Cell, alpha-beta/chemistry
- Receptors, Antigen, T-Cell, alpha-beta/immunology
- Receptors, Antigen, T-Cell, alpha-beta/physiology
- Staphylococcus aureus/immunology
- Superantigens/chemistry
- Superantigens/immunology
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Affiliation(s)
- H Li
- Center for Advanced Research in Biotechnology, University of Maryland Biotechnology Institute, Rockville 20850, USA
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19
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Leder L, Llera A, Lavoie PM, Lebedeva MI, Li H, Sékaly RP, Bohach GA, Gahr PJ, Schlievert PM, Karjalainen K, Mariuzza RA. A mutational analysis of the binding of staphylococcal enterotoxins B and C3 to the T cell receptor beta chain and major histocompatibility complex class II. J Exp Med 1998; 187:823-33. [PMID: 9500785 PMCID: PMC2212189 DOI: 10.1084/jem.187.6.823] [Citation(s) in RCA: 110] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/1997] [Revised: 12/22/1997] [Indexed: 11/23/2022] Open
Abstract
The three-dimensional structure of the complex between a T cell receptor (TCR) beta chain (mouse Vbeta8.2Jbeta2.1Cbeta1) and the superantigen (SAG) staphylococcal enterotoxin C3 (SEC3) has been recently determined to 3.5 resolution. To evaluate the actual contribution of individual SAG residues to stabilizing the beta-SEC3 complex, as well as to investigate the relationship between the affinity of SAGs for TCR and MHC and their ability to activate T cells, we measured the binding of a set of SEC3 and staphylococcal enterotoxin B (SEB) mutants to soluble recombinant TCR beta chain and to the human MHC class II molecule HLA-DR1. Affinities were determined by sedimentation equilibrium and/or surface plasmon detection, while mitogenic potency was assessed using T cells from rearrangement-deficient TCR transgenic mice. We show that there is a clear and simple relationship between the affinity of SAGs for the TCR and their biological activity: the tighter the binding of a particular mutant of SEC3 or SEB to the TCR beta chain, the greater its ability to stimulate T cells. We also find that there is an interplay between TCR-SAG and SAG-MHC interactions in determining mitogenic potency, such that a small increase in the affinity of a SAG for MHC can overcome a large decrease in the SAG's affinity for the TCR. Finally, we observe that those SEC3 residues that make the greatest energetic contribution to stabilizing the beta-SEC3 complex ("hot spot" residues) are strictly conserved among enterotoxins reactive with mouse Vbeta8.2, thereby providing a basis for understanding why SAGs having other residues at these positions show different Vbeta-binding specificities.
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Affiliation(s)
- L Leder
- Center for Advanced Research in Biotechnology, University of Maryland Biotechnology Institute, Rockville, Maryland 20850, USA
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20
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Wendt H, Leder L, Härmä H, Jelesarov I, Baici A, Bosshard HR. Very rapid, ionic strength-dependent association and folding of a heterodimeric leucine zipper. Biochemistry 1997; 36:204-13. [PMID: 8993335 DOI: 10.1021/bi961672y] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Leucine zippers (coiled coils) are dimerization motifs found in several DNA-binding transcription factors. A parallel leucine zipper composed of the acidic chain X1-EYQALEKEVAQLEAENX2-ALEKEVAQLEHEG-amide and the basic chain X1-EYQALKKKVAQLKAKNX2ALKKKVAQLKHKG-amide was designed to study the kinetics of folding of a heterodimeric leucine zipper and to investigate the role of electrostatic attraction between oppositely charged peptide chains to the folding reaction. Each peptide alone did not form a leucine zipper at ionic strength (mu) < 1 M because of electrostatic repulsion between like charges in a homodimer. Therefore, the formation of the heterodimeric leucine zipper could be investigated by simple mixing of acidic and basic chains. To monitor folding, a fluorescent label was located either at the N-terminus (X1 = fluorescein-GGG, X2 = Q) or in the center of the coiled coil (X1 = acetyl, X2 = W). Folding could be described by a simple two-state reaction involving the disordered monomers and the folded heterodimer. The same bimolecular rate constant (k(on)) was observed independent of the location of the fluorescent label, indicating that both fluorescence probes monitored the same reaction. Lowering of the ionic strength increased k(on) from 4 x 10(6) M-1 s-1 (mu = 525 mM) to about 5 x 10(7) M-1 s-1 (mu = 74 mM). When extrapolated to mu = O, k(on) was approximately 10(9) M-1 s-1, which is near the diffusion limit. In contrast, the rate of dissociation depended very weakly on ionic strength; k(off) decreased only by about 2-fold when mu was lowered from 525 to 74 mM. Equilibrium association constants (Ka) of the heterodimeric zippers measured directly and calculated from kinetic constants (Ka = k(on)/k(off) were in good agreement. The observed two-state mechanism, the strong dependence on ionic strength of k(on) but not of k(off), and the nearly diffusion-limited association rate at very low ionic strength point to a folding pathway in which the formation of an electrostatically stabilized dimeric intermediate may be rate-limiting and the subsequent folding to the final dimer is very rapid and follows a "down-hill" free energy landscape. The small increase of k(off) at increasing ionic strength indicates a minor contribution of electrostatics to the stability of the folded leucine zipper.
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Affiliation(s)
- H Wendt
- Biochemisches Institut der Universität Zürich, Switzerland
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21
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Abstract
Our understanding of the energetics that govern antigen-antibody recognition lags behind the increasingly rapid accumulation of structural information on antigen-antibody complexes. Thanks to the development of highly sensitive microcalorimeters, the thermodynamic parameters of antigen-antibody interactions can now be measured with precision and using only nanomole quantities of protein. The method of choice is isothermal titration calorimetry, in which a solution of the antibody (or antigen) is titrated with small aliquots of the antigen (or antibody) and the heat change accompanying the formation of the antigen-antibody complex is measured with a sensitivity as high as 0.1 μcal s-1. The free energy of binding (DeltaG), the binding enthalpy (DeltaH), and the binding entropy (DeltaS) are usually obtained from a single experiment, and no spectroscopic or radioactive label must be introduced into the antigen or antibody. The often large and negative change in heat capacity (DeltaCp) accompanying the formation of an antigen-antibody complex is obtained from DeltaH measured at different temperatures. The basic theory and the principle of the measurements are reviewed and illustrated by examples. The thermodynamic parameters relate to the dynamic physical forces that govern the association of the freely moving antigen and antibody into a well-structured and unique complex. This information complements the static picture of the antigen-antibody complex that results from X-ray diffraction analysis. Attempts to correlate dynamic and static aspects are discussed briefly.
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Affiliation(s)
- I Jelesarov
- Department of Biochemistry, University of Zurich, Zurich, CH-8057, Switzerland
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22
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Leder L, Berger C, Bornhauser S, Wendt H, Ackermann F, Jelesarov I, Bosshard HR. Spectroscopic, calorimetric, and kinetic demonstration of conformational adaptation in peptide-antibody recognition. Biochemistry 1995; 34:16509-18. [PMID: 8845380 DOI: 10.1021/bi00050a035] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Little is known about the extent to which protein flexibility contributes to antigen-antibody recognition and cross-reactivity. Using short coil peptides (leucine zippers) as model antigens, we demonstrate that a monoclonal antibody can force a noncognate peptide into a conformation that is similar to the conformation of the cognate peptide against which the monoclonal antibody is directed. Monoclonal antibodies 29AB and 13AD were raised against the 29-residue peptide LZ (Ac-EYEALEKKLAALEAKLQALEKKLEALEHG-amide) that forms a very stable coiled coil. The two antibodies cross-reacted strongly with the random coil analogue LZ(7P14P) that contains Lys-->Pro and Ala-->Pro substitutions in positions 7 and 14, respectively. The antibody-bound peptide LZ(7P14P) adopted an altered conformation that possibly was coiled coil-like, as shown by CD difference spectroscopy and fluorescence quenching experiments on coumarin-labeled peptides. Isothermal titration calorimetry revealed that the cross-reaction of antibodies 13AD and 29AB with the random coil peptide LZ(7P14P) exhibited a large unfavorable entropy. This, however, was strongly compensated by a more favorable enthalpy, resulting in only a small difference between the association constants for peptide LZ and LZ(7P14P), respectively. To investigate the opposite type of cross-reaction, monoclonal antibody 42PF was raised against the random coil peptide LZ(7P14P). 42PF cross-reacted with coiled coil peptide LZ by forcing it to dissociate into single chains. Enthalpy/entropy compensation again enabled the cross-reaction, which now was entropically favored and enthalpically disfavored. The rate of reaction of antibody 42PF with peptide LZ was controlled by the rate of dissociation of LZ into single chains. This observation, as well as the generally much slower reaction rate with the noncognate peptides, indicated that the cross-reactivity occurred because the antibody selected the conformer of the antigen that binds the strongest, a mechanism we call "induced fit by conformational selection."
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Affiliation(s)
- L Leder
- Biochemisches Institut der Universität Zürich, Switzerland
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23
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Leder L, Wendt H, Schwab C, Jelesarov I, Bornhauser S, Ackermann F, Bosshard HR. Genuine and apparent cross-reaction of polyclonal antibodies to proteins and peptides. Eur J Biochem 1994; 219:73-81. [PMID: 8307037 DOI: 10.1111/j.1432-1033.1994.tb19916.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Antiserum to a native protein may cross-react with the corresponding denatured protein or with peptides. The cross-reaction is either a genuine property of the antibodies or caused by antibodies produced against some unfolded protein contaminating the native protein used for immunization. Appropriate conformation-sensitive immunoassays must be employed to distinguish a genuine from an apparent cross-reaction. In the present study, we have analyzed critically the cross-reaction of rabbit antisera against proteins and peptides. We have distinguished between genuine and apparent cross-reaction with the help of the protein A antibody-capture ELISA, a new conformation-sensitive ELISA format. Three systems were analyzed: cross-reaction of antisera to native yeast and horse cytochrome c with unfolded apo-cytochrome c; cross-reaction of antisera to a coiled-coil leucine-zipper peptide with a homologous random-coil peptide obtained by introducing two proline residues into the leucine-zipper sequence; cross-reaction of antisera to two peptides that correspond to the N-terminal and an internal sequence of ferredoxin: NADP+ reductase (FNR), with the native enzyme. The reaction of the anti-(cytochrome c) sera was clearly due to antibodies produced against unfolded protein, it was an apparent and not a genuine cross-reaction. Furthermore, the apparently cross-reactive antibodies to horse cytochrome c did not discriminate against sequence-related proteins from dog, beef, rabbit and pigeon. In contrast, antibodies to the leucine-zipper peptide did cross-react in a genuine way with the homologous random-coil peptide, that is, the cross-reactive antibodies do not seem to have been produced against the unfolded form of the leucine-zipper peptide. Of the two anti-peptide sera the one against the unstructured and highly accessible N-terminal segment reacted strongly with the native protein. The second serum against a solvent-accessible turn-like sequence of FNR showed apparent cross-reactivity: antibodies recognizing the native protein were directed against a minor conformational isoform of the free peptide and did not react with the principal form(s) of the free peptide. The generation of cross-reactive antibodies depends on the conformational stability and integrity of the immunogen and on the molecular form of its application, i.e., free, polymerized or carrier-bound. The results clarify the different nature of cross-reactivity of antisera to proteins and peptides. This knowledge is crucial if antisera are to be used as conformation-specific probes.
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Affiliation(s)
- L Leder
- Biochemisches Institut, Universität, Zürich, Switzerland
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24
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Leder L, Bosshard HR. Immunoreactivity of cytochrome c: antibodies to horse cytochrome c distinguish between sequence-related cytochromes only at the level of the 3-D-structure. Biochimie 1994; 76:465-70. [PMID: 7880885 DOI: 10.1016/0300-9084(94)90170-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
It has long been known that antibodies to cytochrome c can distinguish between closely sequence-related cytochromes c. Because the 3-D-structure of the polypeptide chain is virtually identical among eukaryotic cytochromes c, antibody specificity is directed against amino acid substitutions within a common polypeptide folding pattern. The question arises if the specificity is observed at the level of the 3-D-structure (conformational epitopes) and/or at the level of the primary structure (sequential epitopes). Using rabbit sera to horse cytochrome c, we show that discrimination against the host's own cytochrome c (six amino acid changes) occurs exclusively at the 3-D-level and not between peptides with sequences typical for horse and rabbit cytochrome c. Furthermore, deliberate immunization with horse apo-cytochrome c produces antibodies that cannot discriminate efficiently between sequence-related apo-cytochromes c. B-cell tolerance to the host's own protein seems to be restricted to the intact, native cytochrome. These findings bear on the application of antisera to distinguish between closely related proteins.
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Affiliation(s)
- L Leder
- Biochemisches Institut der Universität Zürich, Switzerland
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Moennig V, Leder L, Greiser-Wilke I, Frey HR, Liess B. [A new enzyme immunoassay for the detection of antibodies against the bovine viral diarrhea virus]. Tierarztl Prax 1991; 19:35-8. [PMID: 1646493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
An enzyme-linked immunosorbent assay (ELISA), using the nonstructural protein p125/80 of the bovine viral diarrhoea (BVD) virus as antigen, was used for screening BVD-specific antibodies in 468 bovine sera. The results were compared with those obtained in a standard neutralization test (NT). Both tests reacted positive with 457 sera. The ELISA gave positive results with eight sera which were negative in the NT whereas one serum was positive in the NT and negative in the ELISA. Two sera could not be tested in the NT because they were toxic for the cultured cells. In addition the sera were screened in an ELISA using the equivalent heterologous nonstructural protein of hog cholera virus as antigen. The results obtained in both ELISAs showed a correlation of 94%.
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Affiliation(s)
- V Moennig
- Institut für Virologie, Tierärztlichen Hochschule, Hannover
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Abstract
Eight monoclonal antibodies directed against the hog cholera virus (HCV) strain Alfort/187 and displaying broad cross-reactivity with other HCV strains were characterized. An enzyme immunoassay on fixed monolayers of porcine or bovine cells infected with 14 different strains and isolates of HCV and 12 bovine viral diarrhea viruses (BVDV), respectively, showed that all antibodies reacted with HCV only. Seven antibodies recognized all HCV tested, thus indicating that they were directed against conserved epitopes. All antibodies neutralized the homologous strain and different patterns of the other HCV tested. Radioimmunoprecipitation analysis showed that the monoclonal antibodies were directed against a doublet of 56-60 kDa, presumably representing the major envelope glycoprotein of HCV. The results of reciprocal antibody blocking assays allowed the mapping of two distinct conserved antigenic domains on this protein.
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Affiliation(s)
- I Greiser-Wilke
- Institute for Virology, Hannover Veterinary School, Federal Republic of Germany
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Moennig V, Schagemann G, Dahle J, Greiser-Wilke I, Leder L. A new approach for the diagnosis of hog cholera. Dtsch Tierarztl Wochenschr 1990; 97:91-3. [PMID: 2178908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Pestiviruses were isolated from seven cases of suspect hog cholera. Using peroxidase conjugates of monoclonal antibodies (Mabs) six isolates were identified as hog cholera viruses (HCV), while one isolate was of ruminant origin, possibly bovine viral diarrhea virus. In parallel attempts were made to develop an ELISA for the detection of HCV-specific antibodies in pig sera. The Mab HCTC26 coated to polystyrol plates efficiently captured the major viral glycoprotein gp53 from crude antigen suspensions prepared from infected cells. The immobilized gp53 served as diagnostic antigen. Five pigs experimentally infected with the HCV strain Glentorf were sequentially bled and the development of antibodies was monitored by neutralization tests and the ELISA. Results showed that both tests detected antibodies simultaneously after infection. Titres measured by ELISA were slightly higher than those registered by neutralization.
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Affiliation(s)
- V Moennig
- Institute for Virology, Veterinary School Hannover
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