1
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Daffern N, Francino-Urdaniz IM, Baumer ZT, Whitehead TA. Standardizing cassette-based deep mutagenesis by Golden Gate assembly. Biotechnol Bioeng 2024; 121:281-290. [PMID: 37750676 PMCID: PMC10841073 DOI: 10.1002/bit.28564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 08/31/2023] [Accepted: 09/10/2023] [Indexed: 09/27/2023]
Abstract
Protocols for the construction of large, deeply mutagenized protein encoding libraries via Golden Gate assembly of synthetic DNA cassettes employ disparate, system-specific methodology. Here we present a standardized Golden Gate method for building user-defined libraries. We demonstrate that a 25 μL reaction, using 40 fmol of input DNA, can generate a library on the order of 1 × 106 members and that reaction volume or input DNA concentration can be scaled up with no losses in transformation efficiency. Such libraries can be constructed from dsDNA cassettes generated either by degenerate oligonucleotides or oligo pools. We demonstrate its real-world effectiveness by building custom, user-defined libraries on the order of 104 -107 unique protein encoding variants for two orthogonal protein engineering systems. We include a detailed protocol and provide several general-use destination vectors.
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Affiliation(s)
- Nicolas Daffern
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, CO 80305, USA
| | | | - Zachary T. Baumer
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, CO 80305, USA
| | - Timothy A. Whitehead
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, CO 80305, USA
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2
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Attenuated Salmonella Typhimurium with truncated LPS and outer membrane-displayed RGD peptide for cancer therapy. Biomed Pharmacother 2022; 155:113682. [PMID: 36095964 DOI: 10.1016/j.biopha.2022.113682] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 09/01/2022] [Accepted: 09/07/2022] [Indexed: 11/21/2022] Open
Abstract
Gram-negative, facultatively anaerobic bacteria Salmonella Typhimurium is a candidate agent or delivery vector for cancer therapy. Effective targeted therapies in addition to radiotherapy, chemotherapy and surgery have been urgently needed as an alternative or supplement. This study expected to further improve the tumor-targeting ability of Salmonella bacteria through genetic modifications. Based on an auxotrophic Salmonella bacterial strain (D2), we constructed Salmonella mutants with altered LPS length to facilitate displaying the RGD4C targeting peptide on the outer membrane surface of Salmonella. The expression of RGD4C peptide in fusion with OmpA was identified by outer membrane protein extraction and WB detection in different mutant strains. However, flow cytometry analysis following immunofluorescence staining demonstrated that the extracellular length of Salmonella LPS did affect the surface display of RGD4C peptide. The strain D2-RGD4C that synthesized intact LPS including lipid A, core oligosaccharides and O antigen polysaccharides could hardly display RGD4C peptide, showing the same fluorescence signal intensity as the strains not expressing RGD4C peptide. Among different strains, D2 ∆rfaJ-RGD4C that synthesized truncated LPS including lipid A and partial core oligosaccharides was capable of displaying RGD4C peptide most efficiently and showed the highest ability to target HUVECs expressing αV integrin and tumor tissue with abundant neovascularization. Animal experiments also demonstrated that this tumor-targeting attenuated Salmonella strain to simultaneously deliver endostatin and TRAIL, two agents with different anti-tumor activities, could significantly inhibit tumor growth and prolong mouse survival. Thus, our studies revealed that Salmonella could be genetically engineered to improve its tumor targeting via the truncation of LPS and surface display of targeting peptides, thereby eliciting superior anti-tumor effects through targeted delivery of drug molecules.
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3
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Vasina M, Velecký J, Planas-Iglesias J, Marques SM, Skarupova J, Damborsky J, Bednar D, Mazurenko S, Prokop Z. Tools for computational design and high-throughput screening of therapeutic enzymes. Adv Drug Deliv Rev 2022; 183:114143. [PMID: 35167900 DOI: 10.1016/j.addr.2022.114143] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2021] [Revised: 02/04/2022] [Accepted: 02/09/2022] [Indexed: 12/16/2022]
Abstract
Therapeutic enzymes are valuable biopharmaceuticals in various biomedical applications. They have been successfully applied for fibrinolysis, cancer treatment, enzyme replacement therapies, and the treatment of rare diseases. Still, there is a permanent demand to find new or better therapeutic enzymes, which would be sufficiently soluble, stable, and active to meet specific medical needs. Here, we highlight the benefits of coupling computational approaches with high-throughput experimental technologies, which significantly accelerate the identification and engineering of catalytic therapeutic agents. New enzymes can be identified in genomic and metagenomic databases, which grow thanks to next-generation sequencing technologies exponentially. Computational design and machine learning methods are being developed to improve catalytically potent enzymes and predict their properties to guide the selection of target enzymes. High-throughput experimental pipelines, increasingly relying on microfluidics, ensure functional screening and biochemical characterization of target enzymes to reach efficient therapeutic enzymes.
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Affiliation(s)
- Michal Vasina
- Loschmidt Laboratories, Department of Experimental Biology, Faculty of Science, Masaryk University, Kotlarska 2, Brno, Czech Republic; Loschmidt Laboratories, RECETOX, Faculty of Science, Masaryk University, Kotlarska 2, Brno, Czech Republic; International Clinical Research Centre, St. Anne's University Hospital, Pekarska 53, Brno, Czech Republic
| | - Jan Velecký
- Loschmidt Laboratories, Department of Experimental Biology, Faculty of Science, Masaryk University, Kotlarska 2, Brno, Czech Republic; Loschmidt Laboratories, RECETOX, Faculty of Science, Masaryk University, Kotlarska 2, Brno, Czech Republic
| | - Joan Planas-Iglesias
- Loschmidt Laboratories, Department of Experimental Biology, Faculty of Science, Masaryk University, Kotlarska 2, Brno, Czech Republic; Loschmidt Laboratories, RECETOX, Faculty of Science, Masaryk University, Kotlarska 2, Brno, Czech Republic; International Clinical Research Centre, St. Anne's University Hospital, Pekarska 53, Brno, Czech Republic
| | - Sergio M Marques
- Loschmidt Laboratories, Department of Experimental Biology, Faculty of Science, Masaryk University, Kotlarska 2, Brno, Czech Republic; Loschmidt Laboratories, RECETOX, Faculty of Science, Masaryk University, Kotlarska 2, Brno, Czech Republic; International Clinical Research Centre, St. Anne's University Hospital, Pekarska 53, Brno, Czech Republic
| | - Jana Skarupova
- Loschmidt Laboratories, Department of Experimental Biology, Faculty of Science, Masaryk University, Kotlarska 2, Brno, Czech Republic; Loschmidt Laboratories, RECETOX, Faculty of Science, Masaryk University, Kotlarska 2, Brno, Czech Republic
| | - Jiri Damborsky
- Loschmidt Laboratories, Department of Experimental Biology, Faculty of Science, Masaryk University, Kotlarska 2, Brno, Czech Republic; Loschmidt Laboratories, RECETOX, Faculty of Science, Masaryk University, Kotlarska 2, Brno, Czech Republic; International Clinical Research Centre, St. Anne's University Hospital, Pekarska 53, Brno, Czech Republic; Enantis, INBIT, Kamenice 34, Brno, Czech Republic
| | - David Bednar
- Loschmidt Laboratories, Department of Experimental Biology, Faculty of Science, Masaryk University, Kotlarska 2, Brno, Czech Republic; Loschmidt Laboratories, RECETOX, Faculty of Science, Masaryk University, Kotlarska 2, Brno, Czech Republic; International Clinical Research Centre, St. Anne's University Hospital, Pekarska 53, Brno, Czech Republic.
| | - Stanislav Mazurenko
- Loschmidt Laboratories, Department of Experimental Biology, Faculty of Science, Masaryk University, Kotlarska 2, Brno, Czech Republic; Loschmidt Laboratories, RECETOX, Faculty of Science, Masaryk University, Kotlarska 2, Brno, Czech Republic; International Clinical Research Centre, St. Anne's University Hospital, Pekarska 53, Brno, Czech Republic.
| | - Zbynek Prokop
- Loschmidt Laboratories, Department of Experimental Biology, Faculty of Science, Masaryk University, Kotlarska 2, Brno, Czech Republic; Loschmidt Laboratories, RECETOX, Faculty of Science, Masaryk University, Kotlarska 2, Brno, Czech Republic; International Clinical Research Centre, St. Anne's University Hospital, Pekarska 53, Brno, Czech Republic.
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4
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Dyer RP, Weiss GA. Making the cut with protease engineering. Cell Chem Biol 2022; 29:177-190. [PMID: 34921772 PMCID: PMC9127713 DOI: 10.1016/j.chembiol.2021.12.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 07/30/2021] [Accepted: 11/29/2021] [Indexed: 12/30/2022]
Abstract
Proteases cut with enviable precision and regulate diverse molecular events in biology. Such qualities drive a seemingly inexhaustible appetite for proteases with new activities and capabilities. Comprising 25% of the total industrial enzyme market, proteases appear in consumer goods, such as detergents, textile processing, and numerous foods; additionally, proteases include 25 US Food and Drug Administration-approved medicines and various research tools. Recent advances in protease engineering strategies address target specificity, catalytic efficiency, and stability. This guide to protease engineering surveys best practices and emerging strategies. We further highlight gaps and flexibilities inherent to each system that suggest opportunities for new technology development along with engineered proteases to solve challenges in proteomics, protein sequencing, and synthetic gene circuits.
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Affiliation(s)
- Rebekah P Dyer
- Department of Molecular Biology and Biochemistry, University of California, Irvine, 1102 NS-2, Irvine, CA 92697-2025, USA
| | - Gregory A Weiss
- Department of Chemistry, University of California, Irvine, 1102 NS-2, Irvine, CA 92697-2025, USA; Department of Molecular Biology and Biochemistry, University of California, Irvine, 1102 NS-2, Irvine, CA 92697-2025, USA; Department of Pharmaceutical Sciences, University of California, Irvine, 1102 NS-2, Irvine, CA 92697-2025, USA.
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5
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El Harrar T, Davari MD, Jaeger KE, Schwaneberg U, Gohlke H. Critical assessment of structure-based approaches to improve protein resistance in aqueous ionic liquids by enzyme-wide saturation mutagenesis. Comput Struct Biotechnol J 2022; 20:399-409. [PMID: 35070165 PMCID: PMC8752993 DOI: 10.1016/j.csbj.2021.12.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Revised: 12/10/2021] [Accepted: 12/11/2021] [Indexed: 12/12/2022] Open
Abstract
Ionic liquids (IL) and aqueous ionic liquids (aIL) are attractive (co-)solvents for green industrial processes involving biocatalysts, but often reduce enzyme activity. Experimental and computational methods are applied to predict favorable substitution sites and, most often, subsequent site-directed surface charge modifications are introduced to enhance enzyme resistance towards aIL. However, almost no studies evaluate the prediction precision with random mutagenesis or the application of simple data-driven filtering processes. Here, we systematically and rigorously evaluated the performance of 22 previously described structure-based approaches to increase enzyme resistance to aIL based on an experimental complete site-saturation mutagenesis library of Bacillus subtilis Lipase A (BsLipA) screened against four aIL. We show that, surprisingly, most of the approaches yield low gain-in-precision (GiP) values, particularly for predicting relevant positions: 14 approaches perform worse than random mutagenesis. Encouragingly, exploiting experimental information on the thermostability of BsLipA or structural weak spots of BsLipA predicted by rigidity theory yields GiP = 3.03 and 2.39 for relevant variants and GiP = 1.61 and 1.41 for relevant positions. Combining five simple-to-compute physicochemical and evolutionary properties substantially increases the precision of predicting relevant variants and positions, yielding GiP = 3.35 and 1.29. Finally, combining these properties with predictions of structural weak spots identified by rigidity theory additionally improves GiP for relevant variants up to 4-fold to ∼10 and sustains or increases GiP for relevant positions, resulting in a prediction precision of ∼90% compared to ∼9% in random mutagenesis. This combination should be applicable to other enzyme systems for guiding protein engineering approaches towards improved aIL resistance.
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Affiliation(s)
- Till El Harrar
- Institute of Biotechnology, RWTH Aachen University, 52074 Aachen, Germany
- John-von-Neumann-Institute for Computing (NIC), Jülich Supercomputing Centre (JSC), Institute of Biological Information Processing (IBI-7: Structural Biochemistry), and Institute of Bio- and Geosciences (IBG-4: Bioinformatics), Forschungszentrum Jülich GmbH, 52428 Jülich, Germany
| | - Mehdi D. Davari
- Department of Bioorganic Chemistry, Leibniz Institute of Plant Biochemistry, 06120 Halle, Germany
| | - Karl-Erich Jaeger
- Institute of Molecular Enzyme Technology, Heinrich Heine University Düsseldorf, 52428 Jülich, Germany
- Institute of Bio- and Geosciences IBG-1: Biotechnology, Forschungszentrum Jülich GmbH, 52428 Jülich, Germany
| | - Ulrich Schwaneberg
- Institute of Biotechnology, RWTH Aachen University, 52074 Aachen, Germany
- DWI – Leibniz Institute for Interactive Materials e.V., 52074 Aachen, Germany
| | - Holger Gohlke
- John-von-Neumann-Institute for Computing (NIC), Jülich Supercomputing Centre (JSC), Institute of Biological Information Processing (IBI-7: Structural Biochemistry), and Institute of Bio- and Geosciences (IBG-4: Bioinformatics), Forschungszentrum Jülich GmbH, 52428 Jülich, Germany
- Institute for Pharmaceutical and Medicinal Chemistry, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany
- Corresponding author at: John-von-Neumann-Institute for Computing (NIC), Jülich Supercomputing Centre (JSC), Institute of Biological Information Processing (IBI-7: Structural Biochemistry), and Institute of Bio- and Geosciences (IBG-4: Bioinformatics), Forschungszentrum Jülich GmbH, Wilhelm-Johnen-Str., 52428 Jülich, Germany.
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6
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Ali M, Ishqi HM, Husain Q. Enzyme engineering: Reshaping the biocatalytic functions. Biotechnol Bioeng 2020; 117:1877-1894. [DOI: 10.1002/bit.27329] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 01/13/2020] [Accepted: 03/09/2020] [Indexed: 12/19/2022]
Affiliation(s)
- Misha Ali
- Department of Biochemistry, Faculty of Life SciencesAligarh Muslim University Aligarh Uttar Pradesh India
| | | | - Qayyum Husain
- Department of Biochemistry, Faculty of Life SciencesAligarh Muslim University Aligarh Uttar Pradesh India
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7
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Newton MS, Cabezas-Perusse Y, Tong CL, Seelig B. In Vitro Selection of Peptides and Proteins-Advantages of mRNA Display. ACS Synth Biol 2020; 9:181-190. [PMID: 31891492 DOI: 10.1021/acssynbio.9b00419] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
mRNA display is a robust in vitro selection technique that allows the selection of peptides and proteins with desired functions from libraries of trillions of variants. mRNA display relies upon a covalent linkage between a protein and its encoding mRNA molecule; the power of the technique stems from the stability of this link, and the large degree of control over experimental conditions afforded to the researcher. This article describes the major advantages that make mRNA display the method of choice among comparable in vivo and in vitro methods, including cell-surface display, phage display, and ribosomal display. We also describe innovative techniques that harness mRNA display for directed evolution, protein engineering, and drug discovery.
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Affiliation(s)
- Matilda S. Newton
- Department of Biochemistry, Molecular Biology and Biophysics & BioTechnology Institute, University of Minnesota, 1479 Gortner Avenue, St. Paul, Minnesota 55108, United States
- Department of Molecular, Cellular, and Developmental Biology & Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Yari Cabezas-Perusse
- Department of Biochemistry, Molecular Biology and Biophysics & BioTechnology Institute, University of Minnesota, 1479 Gortner Avenue, St. Paul, Minnesota 55108, United States
| | - Cher Ling Tong
- Department of Biochemistry, Molecular Biology and Biophysics & BioTechnology Institute, University of Minnesota, 1479 Gortner Avenue, St. Paul, Minnesota 55108, United States
| | - Burckhard Seelig
- Department of Biochemistry, Molecular Biology and Biophysics & BioTechnology Institute, University of Minnesota, 1479 Gortner Avenue, St. Paul, Minnesota 55108, United States
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8
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Adrian-Segarra JM, Sreenivasan K, Gajawada P, Lörchner H, Braun T, Pöling J. The AB loop of oncostatin M (OSM) determines species-specific signaling in humans and mice. J Biol Chem 2018; 293:20181-20199. [PMID: 30373773 DOI: 10.1074/jbc.ra118.004375] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 10/12/2018] [Indexed: 11/06/2022] Open
Abstract
The pleiotropic interleukin-6 (IL-6)-type cytokine oncostatin M (OSM) signals in multiple cell types, affecting processes such as cell differentiation, hematopoiesis, and inflammation. In humans, OSM exerts its effects through activation of either of two different heterodimeric receptor complexes, formed by glycoprotein 130 (gp130) and either OSM receptor (OSMR) or leukemia inhibitory factor receptor (LIFR). In contrast, the mouse OSM orthologue acts mainly through dimers containing OSMR and gp130 and shows limited activity through mouse LIFR. Despite their structural similarity, neither human nor mouse OSM signal through the other species' OSMR. The molecular basis for such species-specific signaling, however, remains poorly understood. To identify key molecular features of OSM that determine receptor activation in humans and mice, we generated chimeric mouse-human cytokines. Replacing regions within binding site III of murine OSM with the human equivalents showed that the cytokine's AB loop was critical for receptor selection. Substitutions of individual amino acids within this region demonstrated that residues Asn-37, Thr-40, and Asp-42 of the murine cytokine were responsible for limited LIFR activation and absence of human OSMR/LIFR signaling. In human OSM, Lys-44 appeared to be the main residue preventing mouse OSMR activation. Our data reveal that individual amino acids within the AB loop of OSM determine species-specific activities. These mutations might reflect a key step in the evolutionary process of this cytokine, in which receptor promiscuity gives way to ligand-receptor specialization.
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Affiliation(s)
- Juan M Adrian-Segarra
- From the Department of Cardiac Development and Remodeling, Max Planck Institute for Heart and Lung Research, Ludwigstrasse 43, D-61231 Bad Nauheim, Germany and
| | - Krishnamoorthy Sreenivasan
- From the Department of Cardiac Development and Remodeling, Max Planck Institute for Heart and Lung Research, Ludwigstrasse 43, D-61231 Bad Nauheim, Germany and
| | - Praveen Gajawada
- From the Department of Cardiac Development and Remodeling, Max Planck Institute for Heart and Lung Research, Ludwigstrasse 43, D-61231 Bad Nauheim, Germany and
| | - Holger Lörchner
- From the Department of Cardiac Development and Remodeling, Max Planck Institute for Heart and Lung Research, Ludwigstrasse 43, D-61231 Bad Nauheim, Germany and; the German Centre for Cardiovascular Research (DZHK), Partner site Rhein-Main, Frankfurt am Main, Germany
| | - Thomas Braun
- From the Department of Cardiac Development and Remodeling, Max Planck Institute for Heart and Lung Research, Ludwigstrasse 43, D-61231 Bad Nauheim, Germany and; the German Centre for Cardiovascular Research (DZHK), Partner site Rhein-Main, Frankfurt am Main, Germany.
| | - Jochen Pöling
- From the Department of Cardiac Development and Remodeling, Max Planck Institute for Heart and Lung Research, Ludwigstrasse 43, D-61231 Bad Nauheim, Germany and; the German Centre for Cardiovascular Research (DZHK), Partner site Rhein-Main, Frankfurt am Main, Germany.
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9
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Abstract
Directed evolution is a powerful technique for generating tailor-made enzymes for a wide range of biocatalytic applications. Following the principles of natural evolution, iterative cycles of mutagenesis and screening or selection are applied to modify protein properties, enhance catalytic activities, or develop completely new protein catalysts for non-natural chemical transformations. This review briefly surveys the experimental methods used to generate genetic diversity and screen or select for improved enzyme variants. Emphasis is placed on a key challenge, namely how to generate novel catalytic activities that expand the scope of natural reactions. Two particularly effective strategies, exploiting catalytic promiscuity and rational design, are illustrated by representative examples of successfully evolved enzymes. Opportunities for extending these approaches to more complex biocatalytic systems are also considered.
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Affiliation(s)
- Cathleen Zeymer
- Laboratory of Organic Chemistry, ETH Zürich, CH-8093 Zürich, Switzerland;,
| | - Donald Hilvert
- Laboratory of Organic Chemistry, ETH Zürich, CH-8093 Zürich, Switzerland;,
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10
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Bunzel HA, Garrabou X, Pott M, Hilvert D. Speeding up enzyme discovery and engineering with ultrahigh-throughput methods. Curr Opin Struct Biol 2018; 48:149-156. [PMID: 29413955 DOI: 10.1016/j.sbi.2017.12.010] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Accepted: 12/26/2017] [Indexed: 01/24/2023]
Abstract
Exploring the sequence space of enzyme catalysts is ultimately a numbers game. Ultrahigh-throughput screening methods for rapid analysis of millions of variants are therefore increasingly important for investigating sequence-function relationships, searching large metagenomic libraries for interesting activities, and accelerating enzyme evolution in the laboratory. Recent applications of such technologies are reviewed here, with a particular focus on the practical benefits of droplet-based microfluidics for the directed evolution of natural and artificial enzymes. Broader implementation of such rapid, cost-effective screening technologies is likely to redefine the way enzymes are studied and engineered for academic and industrial purposes.
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Affiliation(s)
- Hans Adrian Bunzel
- Laboratory of Organic Chemistry, ETH Zurich, Zurich CH-8093, Switzerland
| | - Xavier Garrabou
- Laboratory of Organic Chemistry, ETH Zurich, Zurich CH-8093, Switzerland
| | - Moritz Pott
- Laboratory of Organic Chemistry, ETH Zurich, Zurich CH-8093, Switzerland
| | - Donald Hilvert
- Laboratory of Organic Chemistry, ETH Zurich, Zurich CH-8093, Switzerland.
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11
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Frei CS, Wang Z, Qian S, Deutsch S, Sutter M, Cirino PC. Analysis of amino acid substitutions in AraC variants that respond to triacetic acid lactone. Protein Sci 2016; 25:804-14. [PMID: 26749125 DOI: 10.1002/pro.2873] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Accepted: 01/04/2016] [Indexed: 12/21/2022]
Abstract
The Escherichia coli regulatory protein AraC regulates expression of ara genes in response to l-arabinose. In efforts to develop genetically encoded molecular reporters, we previously engineered an AraC variant that responds to the compound triacetic acid lactone (TAL). This variant (named "AraC-TAL1") was isolated by screening a library of AraC variants, in which five amino acid positions in the ligand-binding pocket were simultaneously randomized. Screening was carried out through multiple rounds of alternating positive and negative fluorescence-activated cell sorting. Here we show that changing the screening protocol results in the identification of different TAL-responsive variants (nine new variants). Individual substituted residues within these variants were found to primarily act cooperatively toward the gene expression response. Finally, X-ray diffraction was used to solve the crystal structure of the apo AraC-TAL1 ligand-binding domain. The resolved crystal structure confirms that this variant takes on a structure nearly identical to the apo wild-type AraC ligand-binding domain (root-mean-square deviation 0.93 Å), suggesting that AraC-TAL1 behaves similar to wild-type with regard to ligand recognition and gene regulation. Our results provide amino acid sequence-function data sets for training and validating AraC modeling studies, and contribute to our understanding of how to design new biosensors based on AraC.
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Affiliation(s)
- Christopher S Frei
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas, 77204
| | - Zhiqing Wang
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas, 77204
| | - Shuai Qian
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas, 77204
| | - Samuel Deutsch
- Joint Genome Institute, 2800 Mitchell Drive Walnut Creek, California, 94598
| | - Markus Sutter
- Joint Genome Institute, 2800 Mitchell Drive Walnut Creek, California, 94598
| | - Patrick C Cirino
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas, 77204
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12
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Ramesh B, Frei CS, Cirino PC, Varadarajan N. Functional enrichment by direct plasmid recovery after fluorescence activated cell sorting. Biotechniques 2015; 59:157-61. [PMID: 26345509 DOI: 10.2144/000114329] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Accepted: 07/02/2015] [Indexed: 11/23/2022] Open
Abstract
Iterative screening of expressed protein libraries using fluorescence-activated cell sorting (FACS) typically involves culturing the pooled clones after each sort. In these experiments, if cell viability is compromised by the sort conditions and/or expression of the target protein(s), rescue PCR provides an alternative to culturing but requires re-cloning and can introduce amplification bias. We have optimized a simple protocol using commercially available reagents to directly recover plasmid DNA from sorted cells for subsequent transformation. We tested our protocol with 2 different screening systems in which <10% of sorted cells survive culturing and demonstrate that >60% of the sorted cell population was recovered.
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Affiliation(s)
- Balakrishnan Ramesh
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, TX
| | - Christopher S Frei
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, TX
| | - Patrick C Cirino
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, TX
| | - Navin Varadarajan
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, TX
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13
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Yi L, Taft JM, Li Q, Gebhard MC, Georgiou G, Iverson BL. Yeast Endoplasmic Reticulum Sequestration Screening for the Engineering of Proteases from Libraries Expressed in Yeast. Methods Mol Biol 2015; 1319:81-93. [PMID: 26060071 DOI: 10.1007/978-1-4939-2748-7_5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
There is significant interest in engineering proteases with desired proteolytic properties. We describe a high-throughput fluorescence-activated cell sorting (FACS) assay for detecting altered proteolytic activity of protease in yeast, at the single cell level. This assay relies on coupling yeast endoplasmic reticulum (ER) retention, yeast surface display, and FACS analysis. The method described here allows facile screening of large libraries, and of either protease or substrate variants, including the screening of protease libraries against substrate libraries. We demonstrate the application of this technique in the screening of libraries of Tobacco Etch Virus protease (TEV-P) for altered proteolytic activities. In addition, the generality of this method is also validated by other proteases such as human granzyme K and the hepatitis C virus protease, and the human Abelson tyrosine kinase.
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Affiliation(s)
- Li Yi
- Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, TX, 78712, USA,
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14
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Jha RK, Kern TL, Fox DT, M Strauss CE. Engineering an Acinetobacter regulon for biosensing and high-throughput enzyme screening in E. coli via flow cytometry. Nucleic Acids Res 2014; 42:8150-60. [PMID: 24861620 PMCID: PMC4081070 DOI: 10.1093/nar/gku444] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
We created a single cell sorting system to screen for enzyme activity in Escherichia coli producing 3,4 dihydroxy benzoate (34DHB). To do so, we engineered a transcription factor regulon controlling the expression of green fluorescent protein (GFP) for induction by 34DHB. An autoregulated transcription factor, pcaU, was borrowed from Acinetobacter sp ADP1 to E. coli and its promoter region adapted for activity in E. Coli. The engineered pcaU regulon was inducible at >5 μM exogenous 34DHB, making it a sensitive biosensor for this industrially significant nylon precursor. Addition of a second plasmid provided IPTG inducible expression of dehydroshikimate dehydratase enzyme (AsbF), which converts endogenous dehydroshikimate to 34DHB. This system produced GFP fluorescence in an IPTG dose-dependent manner, and was easily detected in single cell on flow cytometer despite a moderate catalytic efficiency of AsbF. Using fluorescence-activated cell sorting (FACS), individual cells carrying the active AsbF could be isolated even when diluted into a decoy population of cells carrying a mutant (inactivated) AsbF variant at one part in a million. The same biosensor was also effective for further optimization of itself. FACS on E. coli carrying randomized loci in the promoter showed several variants with enhanced response to 34DHB.
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Affiliation(s)
- Ramesh K Jha
- Bioscience Division, MS M888, Los Alamos National Laboratory, Los Alamos, NM 87545
| | - Theresa L Kern
- Bioscience Division, MS M888, Los Alamos National Laboratory, Los Alamos, NM 87545
| | - David T Fox
- Bioscience Division, MS M888, Los Alamos National Laboratory, Los Alamos, NM 87545
| | - Charlie E M Strauss
- Bioscience Division, MS M888, Los Alamos National Laboratory, Los Alamos, NM 87545
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15
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GFP reporter screens for the engineering of amino acid degrading enzymes from libraries expressed in bacteria. Methods Mol Biol 2013; 978:31-44. [PMID: 23423887 DOI: 10.1007/978-1-62703-293-3_3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Abstract
There is significant interest in engineering human amino acid degrading enzymes as non-immunogenic chemotherapeutic agents. We describe a high-throughput fluorescence activated cell sorting (FACS) assay for detecting the catalytic activity of amino acid degrading enzymes in bacteria, at the single cell level. This assay relies on coupling the synthesis of the GFP reporter to the catalytic activity of the desired amino acid degrading enzyme in an appropriate E. coli genetic background. The method described here allows facile screening of much larger libraries (10(6)-10(7)) than was previously possible. We demonstrate the application of this technique in the screening of libraries of bacterial and human asparaginases and also for the catalytic optimization of an engineered human methionine gamma lyase.
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16
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17
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Ramesh B, Sendra VG, Cirino PC, Varadarajan N. Single-cell characterization of autotransporter-mediated Escherichia coli surface display of disulfide bond-containing proteins. J Biol Chem 2012; 287:38580-9. [PMID: 23019324 DOI: 10.1074/jbc.m112.388199] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Autotransporters (ATs) are a family of bacterial proteins containing a C-terminal β-barrel-forming domain that facilitates the translocation of N-terminal passenger domain whose functions range from adhesion to proteolysis. Genetic replacement of the native passenger domain with heterologous proteins is an attractive strategy not only for applications such as biocatalysis, live-cell vaccines, and protein engineering but also for gaining mechanistic insights toward understanding AT translocation. The ability of ATs to efficiently display functional recombinant proteins containing multiple disulfides has remained largely controversial. By employing high-throughput single-cell flow cytometry, we have systematically investigated the ability of the Escherichia coli AT Antigen 43 (Ag43) to display two different recombinant reporter proteins, a single-chain antibody (M18 scFv) that contains two disulfides and chymotrypsin that contains four disulfides, by varying the signal peptide and deleting the different domains of the native protein. Our results indicate that only the C-terminal β-barrel and the threaded α-helix are essential for efficient surface display of functional recombinant proteins containing multiple disulfides. These results imply that there are no inherent constraints for functional translocation and display of disulfide bond-containing proteins mediated by the AT system and should open new avenues for protein display and engineering.
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Affiliation(s)
- Balakrishnan Ramesh
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas 77204, USA
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18
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Goldsmith M, Tawfik DS. Directed enzyme evolution: beyond the low-hanging fruit. Curr Opin Struct Biol 2012; 22:406-12. [DOI: 10.1016/j.sbi.2012.03.010] [Citation(s) in RCA: 148] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Revised: 03/14/2012] [Accepted: 03/14/2012] [Indexed: 12/26/2022]
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19
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Chen CP, Hsieh YT, Prijovich ZM, Chuang HY, Chen KC, Lu WC, Tseng Q, Leu YL, Cheng TL, Roffler SR. ECSTASY, an adjustable membrane-tethered/soluble protein expression system for the directed evolution of mammalian proteins. Protein Eng Des Sel 2012; 25:367-75. [PMID: 22691701 DOI: 10.1093/protein/gzs033] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
We describe an adjustable membrane-tethered/soluble protein screening methodology termed ECSTASY (enzyme cleavable surface tethered all-purpose screening system) which combines the power of high-throughput fluorescence-activated cell sorting of membrane-tethered proteins with the flexibility of soluble assays for isolation of improved mammalian recombinant proteins. In this approach, retroviral transduction is employed to stably tether a library of protein variants on the surface of mammalian cells via a glycosyl phosphatidylinositol anchor. High-throughput fluorescence-activated cell sorting is used to array cells expressing properly folded and/or active protein variants on their surface into microtiter culture plates. After culture to expand individual clones, treatment of cells with phosphatidylinositol-phospholipase C releases soluble protein variants for multiplex measurement of protein concentration, activity and/or function. We utilized ECSTASY to rapidly generate human β-glucuronidase variants for cancer therapy by antibody-directed enzyme prodrug therapy with up to 30-fold greater potency to catalyze the hydrolysis of the clinically relevant camptothecin anti-cancer prodrug as compared with wild-type human β-glucuronidase. A variety of recombinant proteins could be adjustably displayed on fibroblasts, suggesting that ECSTASY represents a general, simple and versatile methodology for high-throughput screening to accelerate sequence activity-based evolution of mammalian proteins.
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Affiliation(s)
- Cheng-Pao Chen
- Institute of Biomedical Sciences, Academia Sinica, Taipei 11529, Taiwan
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20
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Decorating microbes: surface display of proteins on Escherichia coli. Trends Biotechnol 2011; 29:79-86. [DOI: 10.1016/j.tibtech.2010.11.003] [Citation(s) in RCA: 165] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2010] [Revised: 11/05/2010] [Accepted: 11/12/2010] [Indexed: 11/22/2022]
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21
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Varadarajan N, Pogson M, Georgiou G, Iverson BL. Proteases that can distinguish among different post-translational forms of tyrosine engineered using multicolor flow cytometry. J Am Chem Soc 2010; 131:18186-90. [PMID: 19924991 DOI: 10.1021/ja907803k] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report the isolation of a highly active (k(cat)/K(M) approximately 10(5) M(-1)s(-1)) variant of the E. coli endopeptidase OmpT that selectively hydrolyzes peptides after 3-nitrotyrosine while effectively discriminating against similar peptides containing unmodified tyrosine (160-fold), sulfotyrosine (3600-fold), phosphotyrosine (>8000-fold), and phosphoserine (>8000-fold). The isolation of endopeptidase variants that can discriminate between substrates based on the post-translational modification of Tyr was made possible by implementing a multicolor flow cytometric assay for the screening of large mutant libraries. For the multicolor assay, a desired selection substrate was used simultaneously with multiple counterselection fluorescent substrates to isolate rare enzyme variants that displayed finely tuned substrate specificity. This work demonstrates that enzymes with exquisite selectivity can be isolated from large libraries using appropriate high throughput screening approaches and constitutes a critical step toward the production of a 3-nitrotyrosine-specific protease useful for proteomic applications.
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Affiliation(s)
- Navin Varadarajan
- Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712, USA
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22
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Pogson M, Georgiou G, Iverson BL. Engineering next generation proteases. Curr Opin Biotechnol 2009; 20:390-7. [PMID: 19709875 PMCID: PMC2763932 DOI: 10.1016/j.copbio.2009.07.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2009] [Accepted: 07/14/2009] [Indexed: 11/17/2022]
Abstract
The engineering of novel and precise sequence specificity into proteases will provide an important route to the development of exciting new tools for analytical, biotechnological, and therapeutic applications. Significant progress has been made in reprogramming protease specificity, largely because of the development of high-throughput assay technologies allowing the isolation of protease variants from large libraries. For example, using directed evolution as well as other approaches, proteases have been reprogrammed to cleave substrates containing a variety of amino acids in the P1 and P1' positions including a post-translationally modified tyrosine, a specificity not yet identified in any naturally occurring protease. Together, these recent advances represent substantial progress that could soon enable the widespread application of engineered proteases.
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Affiliation(s)
- Mark Pogson
- Institute for Cellular and Molecular Biology
| | - George Georgiou
- Institute for Cellular and Molecular Biology
- Dept. of Chemical Engineering
- Dept. of Biomedical Engineering
| | - Brent L. Iverson
- Institute for Cellular and Molecular Biology
- Dept. of Chemistry & Biochemistry
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