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Kulhankova K, Traore S, Cheng X, Benk-Fortin H, Hallée S, Harvey M, Roberge J, Couture F, Kohli S, Gross TJ, Meyerholz DK, Rettig GR, Thommandru B, Kurgan G, Wohlford-Lenane C, Hartigan-O'Connor DJ, Yates BP, Newby GA, Liu DR, Tarantal AF, Guay D, McCray PB. Shuttle peptide delivers base editor RNPs to rhesus monkey airway epithelial cells in vivo. Nat Commun 2023; 14:8051. [PMID: 38052872 PMCID: PMC10698009 DOI: 10.1038/s41467-023-43904-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 11/23/2023] [Indexed: 12/07/2023] Open
Abstract
Gene editing strategies for cystic fibrosis are challenged by the complex barrier properties of airway epithelia. We previously reported that the amphiphilic S10 shuttle peptide non-covalently combined with CRISPR-associated (Cas) ribonucleoprotein (RNP) enabled editing of human and mouse airway epithelial cells. Here, we derive the S315 peptide as an improvement over S10 in delivering base editor RNP. Following intratracheal aerosol delivery of Cy5-labeled peptide in rhesus macaques, we confirm delivery throughout the respiratory tract. Subsequently, we target CCR5 with co-administration of ABE8e-Cas9 RNP and S315. We achieve editing efficiencies of up-to 5.3% in rhesus airway epithelia. Moreover, we document persistence of edited epithelia for up to 12 months in mice. Finally, delivery of ABE8e-Cas9 targeting the CFTR R553X mutation restores anion channel function in cultured human airway epithelia. These results demonstrate the therapeutic potential of base editor delivery with S315 to functionally correct the CFTR R553X mutation in respiratory epithelia.
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Affiliation(s)
| | - Soumba Traore
- Department of Pediatrics, University of Iowa, Iowa City, IA, USA
| | | | | | | | | | | | | | - Sajeev Kohli
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA, USA
| | - Thomas J Gross
- Department of Internal Medicine, University of Iowa, Iowa City, IA, USA
| | | | | | | | - Gavin Kurgan
- Integrated DNA Technologies, Coralville, IA, USA
| | | | - Dennis J Hartigan-O'Connor
- Department of Medical Microbiology and Immunology, School of Medicine, UC Davis, Davis, CA, USA
- California National Primate Research Center, UC Davis, Davis, CA, USA
| | - Bradley P Yates
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Gregory A Newby
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA, USA
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - David R Liu
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA, USA
| | - Alice F Tarantal
- California National Primate Research Center, UC Davis, Davis, CA, USA
- Department of Pediatrics, School of Medicine, UC Davis, Davis, CA, USA
- Department of Cell Biology and Human Anatomy, School of Medicine, UC Davis, Davis, CA, USA
| | | | - Paul B McCray
- Department of Pediatrics, University of Iowa, Iowa City, IA, USA.
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2
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Martyn GD, Veggiani G, Kusebauch U, Morrone SR, Yates BP, Singer AU, Tong J, Manczyk N, Gish G, Sun Z, Kurinov I, Sicheri F, Moran MF, Moritz RL, Sidhu SS. Engineered SH2 Domains for Targeted Phosphoproteomics. ACS Chem Biol 2022; 17:1472-1484. [PMID: 35613471 DOI: 10.1021/acschembio.2c00051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A comprehensive analysis of the phosphoproteome is essential for understanding molecular mechanisms of human diseases. However, current tools used to enrich phosphotyrosine (pTyr) are limited in their applicability and scope. Here, we engineered new superbinder Src-Homology 2 (SH2) domains that enrich diverse sets of pTyr-peptides. We used phage display to select a Fes-SH2 domain variant (superFes; sFes1) with high affinity for pTyr and solved its structure bound to a pTyr-peptide. We performed systematic structure-function analyses of the superbinding mechanisms of sFes1 and superSrc-SH2 (sSrc1), another SH2 superbinder. We grafted the superbinder motifs from sFes1 and sSrc1 into 17 additional SH2 domains and confirmed increased binding affinity for specific pTyr-peptides. Using mass spectrometry (MS), we demonstrated that SH2 superbinders have distinct specificity profiles and superior capabilities to enrich pTyr-peptides. Finally, using combinations of SH2 superbinders as affinity purification (AP) tools we showed that unique subsets of pTyr-peptides can be enriched with unparalleled depth and coverage.
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Affiliation(s)
- Gregory D. Martyn
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, Ontario M5S3E1, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Gianluca Veggiani
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, Ontario M5S3E1, Canada
| | - Ulrike Kusebauch
- Institute for Systems Biology, Seattle, Washington 98109, United States
| | - Seamus R. Morrone
- Institute for Systems Biology, Seattle, Washington 98109, United States
| | - Bradley P. Yates
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, Ontario M5S3E1, Canada
| | - Alex U. Singer
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, Ontario M5S3E1, Canada
| | - Jiefei Tong
- Program in Cell biology, Hospital for Sick Children, Toronto M5G 0A4, Canada
| | - Noah Manczyk
- Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada
| | - Gerald Gish
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada
| | - Zhi Sun
- Institute for Systems Biology, Seattle, Washington 98109, United States
| | - Igor Kurinov
- Department of Chemistry and Chemical Biology, Cornell University, NE-CAT, Argonne, Illinois 60439, United States
| | - Frank Sicheri
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada
| | - Michael F. Moran
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada
- Program in Cell biology, Hospital for Sick Children, Toronto M5G 0A4, Canada
- The Hospital for Sick Children, SPARC Biocentre, Toronto, Ontario M5G 0A4, Canada
| | - Robert L. Moritz
- Institute for Systems Biology, Seattle, Washington 98109, United States
| | - Sachdev S. Sidhu
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, Ontario M5S3E1, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada
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3
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Veggiani G, Yates BP, Martyn GD, Manczyk N, Singer AU, Kurinov I, Sicheri F, Sidhu SS. Panel of Engineered Ubiquitin Variants Targeting the Family of Human Ubiquitin Interacting Motifs. ACS Chem Biol 2022; 17:941-956. [PMID: 35385646 PMCID: PMC9305627 DOI: 10.1021/acschembio.2c00089] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ubiquitin (Ub)-binding domains embedded in intracellular proteins act as readers of the complex Ub code and contribute to regulation of numerous eukaryotic processes. Ub-interacting motifs (UIMs) are short α-helical modular recognition elements whose role in controlling proteostasis and signal transduction has been poorly investigated. Moreover, impaired or aberrant activity of UIM-containing proteins has been implicated in numerous diseases, but targeting modular recognition elements in proteins remains a major challenge. To overcome this limitation, we developed Ub variants (UbVs) that bind to 42 UIMs in the human proteome with high affinity and specificity. Structural analysis of a UbV:UIM complex revealed the molecular determinants of enhanced affinity and specificity. Furthermore, we showed that a UbV targeting a UIM in the cancer-associated Ub-specific protease 28 potently inhibited catalytic activity. Our work demonstrates the versatility of UbVs to target short α-helical Ub receptors with high affinity and specificity. Moreover, the UbVs provide a toolkit to investigate the role of UIMs in regulating and transducing Ub signals and establish a general strategy for the systematic development of probes for Ub-binding domains.
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Affiliation(s)
- Gianluca Veggiani
- Donnelly Centre for Cellular and Biomolecular Research, Banting and Best Department of Medical Research, University of Toronto, 160 College Street, Toronto, Ontario M5S3E1, Canada
| | - Bradley P. Yates
- Donnelly Centre for Cellular and Biomolecular Research, Banting and Best Department of Medical Research, University of Toronto, 160 College Street, Toronto, Ontario M5S3E1, Canada
| | - Gregory D. Martyn
- Donnelly Centre for Cellular and Biomolecular Research, Banting and Best Department of Medical Research, University of Toronto, 160 College Street, Toronto, Ontario M5S3E1, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Noah Manczyk
- Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, Ontario M5G 1X5, Canada
| | - Alex U. Singer
- Donnelly Centre for Cellular and Biomolecular Research, Banting and Best Department of Medical Research, University of Toronto, 160 College Street, Toronto, Ontario M5S3E1, Canada
| | - Igor Kurinov
- Department of Chemistry and Chemical Biology, NE-CAT, Cornell University, Argonne, Illinois 60439, United States
| | - Frank Sicheri
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, Ontario M5G 1X5, Canada
| | - Sachdev S. Sidhu
- Donnelly Centre for Cellular and Biomolecular Research, Banting and Best Department of Medical Research, University of Toronto, 160 College Street, Toronto, Ontario M5S3E1, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada
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4
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Manczyk N, Veggiani G, Gish GD, Yates BP, Ernst A, Sidhu SS, Sicheri F. Dimerization of a ubiquitin variant leads to high affinity interactions with a ubiquitin interacting motif. Protein Sci 2019; 28:848-856. [PMID: 30793400 DOI: 10.1002/pro.3593] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [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: 01/03/2019] [Revised: 02/13/2019] [Accepted: 02/19/2019] [Indexed: 11/06/2022]
Abstract
We previously described structural and functional characterization of the first ubiquitin variant (UbV), UbV.v27.1, engineered by phage display to bind with high affinity to a specific ubiquitin interacting motif (UIM). We identified two substitutions relative to ubiquitin (Gly10Val/His68Tyr) that were critical for enhancing binding affinity but could only rationalize the mechanism of action of the Tyr68 substitution. Here, we extend our characterization and uncover the mechanism by which the Val10 substitution enhances binding affinity. We show that Val10 in UbV.v27.1 drives UbV dimerization through an intermolecular β-strand exchange. Dimerization serves to increase the contact surface between the UIM and UbV and also affords direct contacts between two UIMs through an overall 2:2 binding stoichiometry. Our identification of the role of Val10 in UbV dimerization suggests a general means for the development of dimeric UbVs with improved affinity and specificity relative to their monomeric UbV counterparts. Statement: Previously, we used phage display to engineer a UbV that bound tightly and specifically to a UIM. Here, we discovered that tight binding is partly due to the dimerization of the UbV, which increases the contact surface between the UbV and UIM. We show that UbV dimerization is dependent on the Gly10Val substitution, and posit that dimerization may provide a general means for engineering UbVs with improved binding properties.
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Affiliation(s)
- Noah Manczyk
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada.,Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Gianluca Veggiani
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada.,Donnelly Centre for Cellular and Biomolecular Research, Banting and Best Department of Medical Research, University of Toronto, M5S 3E1 Toronto, Ontario, Canada
| | - Gerald D Gish
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada
| | - Bradley P Yates
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada.,Donnelly Centre for Cellular and Biomolecular Research, Banting and Best Department of Medical Research, University of Toronto, M5S 3E1 Toronto, Ontario, Canada
| | - Andreas Ernst
- Institute of Biochemistry II, Goethe University, Frankfurt am Main 60590, Germany
| | - Sachdev S Sidhu
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada.,Donnelly Centre for Cellular and Biomolecular Research, Banting and Best Department of Medical Research, University of Toronto, M5S 3E1 Toronto, Ontario, Canada
| | - Frank Sicheri
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada.,Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada
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5
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Veggiani G, Huang H, Yates BP, Tong J, Kaneko T, Joshi R, Li SSC, Moran MF, Gish G, Sidhu SS. Engineered SH2 domains with tailored specificities and enhanced affinities for phosphoproteome analysis. Protein Sci 2018; 28:403-413. [PMID: 30431205 DOI: 10.1002/pro.3551] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [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: 10/07/2018] [Revised: 11/09/2018] [Accepted: 11/12/2018] [Indexed: 02/05/2023]
Abstract
Protein phosphorylation is the most abundant post-translational modification in cells. Src homology 2 (SH2) domains specifically recognize phosphorylated tyrosine (pTyr) residues to mediate signaling cascades. A conserved pocket in the SH2 domain binds the pTyr side chain and the EF and BG loops determine binding specificity. By using large phage-displayed libraries, we engineered the EF and BG loops of the Fyn SH2 domain to alter specificity. Engineered SH2 variants exhibited distinct specificity profiles and were able to bind pTyr sites on the epidermal growth factor receptor, which were not recognized by the wild-type Fyn SH2 domain. Furthermore, mass spectrometry showed that SH2 variants with additional mutations in the pTyr-binding pocket that enhanced affinity were highly effective for enrichment of diverse pTyr peptides within the human proteome. These results showed that engineering of the EF and BG loops could be used to tailor SH2 domain specificity, and SH2 variants with diverse specificities and high affinities for pTyr residues enabled more comprehensive analysis of the human phosphoproteome. STATEMENT: Src Homology 2 (SH2) domains are modular domains that recognize phosphorylated tyrosine embedded in proteins, transducing these post-translational modifications into cellular responses. Here we used phage display to engineer hundreds of SH2 domain variants with altered binding specificities and enhanced affinities, which enabled efficient and differential enrichment of the human phosphoproteome for analysis by mass spectrometry. These engineered SH2 domain variants will be useful tools for elucidating the molecular determinants governing SH2 domains binding specificity and for enhancing analysis and understanding of the human phosphoproteome.
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Affiliation(s)
- Gianluca Veggiani
- Department of Biochemistry, University of Toronto, Toronto, Ontario, M5S 1A8, Canada.,Donnelly Centre for Cellular and Biomolecular Research, Banting and Best Department of Medical Research, University of Toronto, Toronto, Ontario, M5S3E1, Canada
| | - Haiming Huang
- Department of Biochemistry, University of Toronto, Toronto, Ontario, M5S 1A8, Canada.,Donnelly Centre for Cellular and Biomolecular Research, Banting and Best Department of Medical Research, University of Toronto, Toronto, Ontario, M5S3E1, Canada
| | - Bradley P Yates
- Department of Biochemistry, University of Toronto, Toronto, Ontario, M5S 1A8, Canada.,Donnelly Centre for Cellular and Biomolecular Research, Banting and Best Department of Medical Research, University of Toronto, Toronto, Ontario, M5S3E1, Canada
| | - Jiefei Tong
- Program in Molecular Structure and Function, The Hospital for Sick Children, Department of Molecular Genetics, University of Toronto, Toronto, Ontario, M5G 0A4, Canada
| | - Tomonori Kaneko
- Department of Biochemistry, Siebens-Drake Medical Research Institute, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, N6A 5C1, Canada
| | - Rakesh Joshi
- Department of Biochemistry, Siebens-Drake Medical Research Institute, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, N6A 5C1, Canada
| | - Shawn S C Li
- Department of Biochemistry, Siebens-Drake Medical Research Institute, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, N6A 5C1, Canada
| | - Michael F Moran
- Program in Molecular Structure and Function, The Hospital for Sick Children, Department of Molecular Genetics, University of Toronto, Toronto, Ontario, M5G 0A4, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Ontario, M5S 3E1, Canada.,The Hospital for Sick Children, SPARC Biocentre, Toronto, Ontario, M5G 0A4, Canada
| | - Gerald Gish
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, M5G 1X5, Canada
| | - Sachdev S Sidhu
- Department of Biochemistry, University of Toronto, Toronto, Ontario, M5S 1A8, Canada.,Donnelly Centre for Cellular and Biomolecular Research, Banting and Best Department of Medical Research, University of Toronto, Toronto, Ontario, M5S3E1, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Ontario, M5S 3E1, Canada
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6
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Manczyk N, Yates BP, Veggiani G, Ernst A, Sicheri F, Sidhu SS. Structural and functional characterization of a ubiquitin variant engineered for tight and specific binding to an alpha-helical ubiquitin interacting motif. Protein Sci 2017; 26:1060-1069. [PMID: 28276594 DOI: 10.1002/pro.3155] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [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: 01/04/2017] [Accepted: 03/06/2017] [Indexed: 12/20/2022]
Abstract
Ubiquitin interacting motifs (UIMs) are short α-helices found in a number of eukaryotic proteins. UIMs interact weakly but specifically with ubiquitin conjugated to other proteins, and in so doing, mediate specific cellular signals. Here we used phage display to generate ubiquitin variants (UbVs) targeting the N-terminal UIM of the yeast Vps27 protein. Selections yielded UbV.v27.1, which recognized the cognate UIM with high specificity relative to other yeast UIMs and bound with an affinity more than two orders of magnitude higher than that of ubiquitin. Structural and mutational studies of the UbV.v27.1-UIM complex revealed the molecular details for the enhanced affinity and specificity of UbV.v27.1, and underscored the importance of changes at the binding interface as well as at positions that do not contact the UIM. Our study highlights the power of the phage display approach for selecting UbVs with unprecedented affinity and high selectivity for particular α-helical UIM domains within proteomes, and it establishes a general approach for the development of inhibitors targeting interactions of this type.
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Affiliation(s)
- Noah Manczyk
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, M5G 1X5, Canada.,Department of Biochemistry, University of Toronto, Toronto, Ontario, M5S 1A8, Canada
| | - Bradley P Yates
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, M5S 1A8, Canada.,Donnelly Centre for Cellular and Biomolecular Research, Banting and Best Department of Medical Research, University of Toronto, Toronto, Ontario, M5S 3E1, Canada
| | - Gianluca Veggiani
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, M5S 1A8, Canada.,Donnelly Centre for Cellular and Biomolecular Research, Banting and Best Department of Medical Research, University of Toronto, Toronto, Ontario, M5S 3E1, Canada
| | - Andreas Ernst
- Institute of Biochemistry II, Faculty of Medicine, Goethe University, Frankfurt am Main, 60590, Germany
| | - Frank Sicheri
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, M5G 1X5, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Ontario, M5S 1A8, Canada.,Department of Biochemistry, University of Toronto, Toronto, Ontario, M5S 1A8, Canada
| | - Sachdev S Sidhu
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, M5S 1A8, Canada.,Donnelly Centre for Cellular and Biomolecular Research, Banting and Best Department of Medical Research, University of Toronto, Toronto, Ontario, M5S 3E1, Canada
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7
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Yates BP, Peck MA, Berget PB. Directed evolution of a fluorogen-activating single chain antibody for function and enhanced brightness in the cytoplasm. Mol Biotechnol 2013; 54:829-41. [PMID: 23242633 DOI: 10.1007/s12033-012-9631-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [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: 02/06/2023]
Abstract
Directed evolution is an exceptionally powerful tool that uses random mutant library generation and screening techniques to engineer or optimize functions of proteins. One class of proteins for which this process is particularly effective is antibodies, where properties such as antigen specificity and affinity can be selected to yield molecules with improved efficacy as molecular labels or in potential therapeutics. Typical antibody structure includes disulfide bonds that are required for stability and proper folding of the domains. However, these bonds are unable to form in the reducing environment of the cytoplasm, stymieing the effectiveness of optimized antibodies in many research applications. We have removed disulfide-forming cysteine residues in a single chain antibody fluorogen-activating protein (FAP), HL4, and employed directed evolution to select a derivative that is capable of activity in the cytoplasm. A subsequent round of directed evolution was targeted at increasing the overall brightness of the fluoromodule (FAP-fluorogen complex). Ultimately, this approach produced a novel FAP that exhibits strong activation of its cognate fluorogen in the reducing environment of the cytoplasm, significantly expanding the range of applications for which fluoromodule technology can be utilized.
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Affiliation(s)
- Bradley P Yates
- Department of Biological Sciences & Molecular Biosensor and Imaging Center, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213, USA
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8
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Falco CN, Dykstra KM, Yates BP, Berget PB. scFv-based fluorogen activating proteins and variable domain inhibitors as fluorescent biosensor platforms. Biotechnol J 2009; 4:1328-36. [PMID: 19606431 DOI: 10.1002/biot.200900075] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Single chain antibodies (scFvs) are engineered proteins composed of IgG variable heavy (V(H)) and variable light (V(L)) domains tethered together by a flexible peptide linker. We have characterized the individual V(H) or V(L) domain activities of several scFvs isolated from a yeast surface-display library for their ability to bind environmentally sensitive fluorogenic dyes causing them to fluoresce. For many of the scFvs, both V(H) and V(L) domains are required for dye binding and fluorescence. The analysis of other scFvs, however, revealed that either the V(H) or the V(L) domain alone is sufficient to cause the fluorogenic dye activation. Furthermore, the inactive complementary domains in the original scFvs either contribute nothing to, or actually inhibit the activity of these active single domains. We have explored the interactions between active variable domains and inactive complementary domains by extensive variable domain swapping through in vitro gene manipulations to create hybrid scFvs. In this study, we demonstrate that significant alteration of the fluorogenic dye activation by the active V(H) or V(L) domains can occur by partnering with different V(H) or V(L) complementary domains in the scFv format. Hybrid scFvs can be generated that have fluorogen-activating domains that are completely inhibited by interactions with other domains. Such hybrid scFvs are excellent platforms for the development of several types of genetically encoded, fluorescence-generating biosensors.
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Affiliation(s)
- Crystal N Falco
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, USA
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