1
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Lightle HE, Kafley P, Lewis TR, Wang RE. Site-specific protein conjugates incorporating Para-Azido-L-Phenylalanine for cellular and in vivo imaging. Methods 2023; 219:95-101. [PMID: 37804961 PMCID: PMC10841489 DOI: 10.1016/j.ymeth.2023.10.001] [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: 08/10/2023] [Revised: 10/04/2023] [Accepted: 10/04/2023] [Indexed: 10/09/2023] Open
Abstract
This work features the use of amber suppression-mediated unnatural amino acid (UAA) incorporation into proteins for various imaging purposes. The site-specific incorporation of the UAA, p-azido-L-phenylalanine (pAzF), provides an azide handle that can be used to complete the strain promoted azide-alkyne click cycloaddition (SPAAC) reaction to introduce an imaging modality such as a fluorophore or a positron emission tomography (PET) tracer on the protein of interest (POI). Such methodology can be pursued directly in mammalian cell lines or on proteins expressed in vitro, thereby conferring a homogeneous pool of protein conjugates. A general procedure for UAA incorporation to use with a site-specific protein labeling method is provided allowing for in vitro and in vivo imaging applications based on the representative proteins PTEN and PD-L1. This approach would help elucidate the cellular or in vivo biological activities of the POI.
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Affiliation(s)
- Hailey E Lightle
- Department of Chemistry, Temple University, 1901 N. 13(th) Street, Philadelphia, PA 19122, USA
| | - Parmila Kafley
- Department of Chemistry, Temple University, 1901 N. 13(th) Street, Philadelphia, PA 19122, USA
| | - Todd R Lewis
- Department of Chemistry, Temple University, 1901 N. 13(th) Street, Philadelphia, PA 19122, USA
| | - Rongsheng E Wang
- Department of Chemistry, Temple University, 1901 N. 13(th) Street, Philadelphia, PA 19122, USA.
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2
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Update of the Pyrrolysyl-tRNA Synthetase/tRNA Pyl Pair and Derivatives for Genetic Code Expansion. J Bacteriol 2023; 205:e0038522. [PMID: 36695595 PMCID: PMC9945579 DOI: 10.1128/jb.00385-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The cotranslational incorporation of pyrrolysine (Pyl), the 22nd proteinogenic amino acid, into proteins in response to the UAG stop codon represents an outstanding example of natural genetic code expansion. Genetic encoding of Pyl is conducted by the pyrrolysyl-tRNA synthetase (PylRS) and its cognate tRNA, tRNAPyl. Owing to the high tolerance of PylRS toward diverse amino acid substrates and great orthogonality in various model organisms, the PylRS/tRNAPyl-derived pairs are ideal for genetic code expansion to insert noncanonical amino acids (ncAAs) into proteins of interest. Since the discovery of cellular components involved in the biosynthesis and genetic encoding of Pyl, synthetic biologists have been enthusiastic about engineering PylRS/tRNAPyl-derived pairs to rewrite the genetic code of living cells. Recently, considerable progress has been made in understanding the molecular phylogeny, biochemical properties, and structural features of the PylRS/tRNAPyl pair, guiding its further engineering and optimization. In this review, we cover the basic and updated knowledge of the PylRS/tRNAPyl pair's unique characteristics that make it an outstanding tool for reprogramming the genetic code. In addition, we summarize the recent efforts to create efficient and (mutually) orthogonal PylRS/tRNAPyl-derived pairs for incorporation of diverse ncAAs by genome mining, rational design, and advanced directed evolution methods.
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3
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Jiang HK, Ambrose NL, Chung CZ, Wang YS, Söll D, Tharp JM. Split aminoacyl-tRNA synthetases for proximity-induced stop codon suppression. Proc Natl Acad Sci U S A 2023; 120:e2219758120. [PMID: 36787361 PMCID: PMC9974479 DOI: 10.1073/pnas.2219758120] [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: 11/18/2022] [Accepted: 01/16/2023] [Indexed: 02/15/2023] Open
Abstract
Synthetic biology tools for regulating gene expression have many useful biotechnology and therapeutic applications. Most tools developed for this purpose control gene expression at the level of transcription, and relatively few methods are available for regulating gene expression at the translational level. Here, we design and engineer split orthogonal aminoacyl-tRNA synthetases (o-aaRS) as unique tools to control gene translation in bacteria and mammalian cells. Using chemically induced dimerization domains, we developed split o-aaRSs that mediate gene expression by conditionally suppressing stop codons in the presence of the small molecules rapamycin and abscisic acid. By activating o-aaRSs, these molecular switches induce stop codon suppression, and in their absence stop codon suppression is turned off. We demonstrate, in Escherichia coli and in human cells, that split o-aaRSs function as genetically encoded AND gates where stop codon suppression is controlled by two distinct molecular inputs. In addition, we show that split o-aaRSs can be used as versatile biosensors to detect therapeutically relevant protein-protein interactions, including those involved in cancer, and those that mediate severe acute respiratory syndrome-coronavirus-2 infection.
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Affiliation(s)
- Han-Kai Jiang
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT06511
- Institute of Biological Chemistry, Academia Sinica, Taipei11529, Taiwan
- Chemical Biology and Molecular Biophysics Program, Taiwan International Graduate Program, Academia Sinica, Taipei11529, Taiwan
- Department of Chemistry, National Tsing Hua University, Hsinchu100044, Taiwan
| | - Nicole L. Ambrose
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT06511
| | - Christina Z. Chung
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT06511
| | - Yane-Shih Wang
- Institute of Biological Chemistry, Academia Sinica, Taipei11529, Taiwan
- Chemical Biology and Molecular Biophysics Program, Taiwan International Graduate Program, Academia Sinica, Taipei11529, Taiwan
- Institute of Biochemical Sciences, National Taiwan University, Taipei10617, Taiwan
| | - Dieter Söll
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT06511
- Department of Chemistry, Yale University, New Haven, CT06511
| | - Jeffery M. Tharp
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN46202
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4
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Guo C, Xu K, Chen C, Wang J, Li H. Site-Specific Synthesis of Protein-Oligo Conjugates through Histidine-Maleimide-Mediated Imidazolidinone Formation. Bioconjug Chem 2022; 33:1885-1891. [DOI: 10.1021/acs.bioconjchem.2c00350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Chun Guo
- R&D Department, Genscript Biotech, 28 Yongxi Street, Nanjing, Jiangsu 211100, China
| | - Kang Xu
- R&D Department, Genscript Biotech, 28 Yongxi Street, Nanjing, Jiangsu 211100, China
| | - Chen Chen
- R&D Department, Genscript Biotech, 28 Yongxi Street, Nanjing, Jiangsu 211100, China
| | - Jianpeng Wang
- R&D Department, Genscript Biotech, 28 Yongxi Street, Nanjing, Jiangsu 211100, China
| | - Hong Li
- R&D Department, Genscript Biotech, 28 Yongxi Street, Nanjing, Jiangsu 211100, China
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5
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Stieglitz JT, Van Deventer JA. High-Throughput Aminoacyl-tRNA Synthetase Engineering for Genetic Code Expansion in Yeast. ACS Synth Biol 2022; 11:2284-2299. [PMID: 35793554 PMCID: PMC10065163 DOI: 10.1021/acssynbio.1c00626] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Protein expression with genetically encoded noncanonical amino acids (ncAAs) benefits a broad range of applications, from the discovery of biological therapeutics to fundamental biological studies. A major factor limiting the use of ncAAs is the lack of orthogonal translation systems (OTSs) that support efficient genetic code expansion at repurposed stop codons. Aminoacyl-tRNA synthetases (aaRSs) have been extensively evolved in Escherichia coli but are not always orthogonal in eukaryotes. In this work, we use a yeast display-based ncAA incorporation reporter platform with fluorescence-activated cell sorting to screen libraries of aaRSs in high throughput for (1) the incorporation of ncAAs not previously encoded in yeast; (2) the improvement of the performance of an existing aaRS; (3) highly selective OTSs capable of discriminating between closely related ncAA analogues; and (4) OTSs exhibiting enhanced polyspecificity to support translation with structurally diverse sets of ncAAs. The number of previously undiscovered aaRS variants we report in this work more than doubles the total number of translationally active aaRSs available for genetic code manipulation in yeast. The success of myriad screening strategies has important implications related to the fundamental properties and evolvability of aaRSs. Furthermore, access to OTSs with diverse activities and specific or polyspecific properties is invaluable for a range of applications within chemical biology, synthetic biology, and protein engineering.
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Affiliation(s)
- Jessica T Stieglitz
- Chemical and Biological Engineering Department, Tufts University, Medford, Massachusetts 02155, United States
| | - James A Van Deventer
- Chemical and Biological Engineering Department, Tufts University, Medford, Massachusetts 02155, United States
- Biomedical Engineering Department, Tufts University, Medford, Massachusetts 02155, United States
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6
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Hans S, Kumar N, Gohil N, Khambhati K, Bhattacharjee G, Deb SS, Maurya R, Kumar V, Reshamwala SMS, Singh V. Rebooting life: engineering non-natural nucleic acids, proteins and metabolites in microorganisms. Microb Cell Fact 2022; 21:100. [PMID: 35643549 PMCID: PMC9148472 DOI: 10.1186/s12934-022-01828-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 05/15/2022] [Indexed: 12/01/2022] Open
Abstract
The surging demand of value-added products has steered the transition of laboratory microbes to microbial cell factories (MCFs) for facilitating production of large quantities of important native and non-native biomolecules. This shift has been possible through rewiring and optimizing different biosynthetic pathways in microbes by exercising frameworks of metabolic engineering and synthetic biology principles. Advances in genome and metabolic engineering have provided a fillip to create novel biomolecules and produce non-natural molecules with multitude of applications. To this end, numerous MCFs have been developed and employed for production of non-natural nucleic acids, proteins and different metabolites to meet various therapeutic, biotechnological and industrial applications. The present review describes recent advances in production of non-natural amino acids, nucleic acids, biofuel candidates and platform chemicals.
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7
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Vanella R, Kovacevic G, Doffini V, Fernández de Santaella J, Nash MA. High-throughput screening, next generation sequencing and machine learning: advanced methods in enzyme engineering. Chem Commun (Camb) 2022; 58:2455-2467. [PMID: 35107442 PMCID: PMC8851469 DOI: 10.1039/d1cc04635g] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Enzyme engineering is an important biotechnological process capable of generating tailored biocatalysts for applications in industrial chemical conversion and biopharma. Typical enhancements sought in enzyme engineering and in vitro evolution campaigns include improved folding stability, catalytic activity, and/or substrate specificity. Despite significant progress in recent years in the areas of high-throughput screening and DNA sequencing, our ability to explore the vast space of functional enzyme sequences remains severely limited. Here, we review the currently available suite of modern methods for enzyme engineering, with a focus on novel readout systems based on enzyme cascades, and new approaches to reaction compartmentalization including single-cell hydrogel encapsulation techniques to achieve a genotype–phenotype link. We further summarize systematic scanning mutagenesis approaches and their merger with deep mutational scanning and massively parallel next-generation DNA sequencing technologies to generate mutability landscapes. Finally, we discuss the implementation of machine learning models for computational prediction of enzyme phenotypic fitness from sequence. This broad overview of current state-of-the-art approaches for enzyme engineering and evolution will aid newcomers and experienced researchers alike in identifying the important challenges that should be addressed to move the field forward. Enzyme engineering is an important biotechnological process capable of generating tailored biocatalysts for applications in industrial chemical conversion and biopharma.![]()
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Affiliation(s)
- Rosario Vanella
- Department of Chemistry, University of Basel, 4058 Basel, Switzerland.,Department of Biosystems Science and Engineering, ETH Zurich, 4058 Basel, Switzerland.
| | - Gordana Kovacevic
- Department of Chemistry, University of Basel, 4058 Basel, Switzerland.,Department of Biosystems Science and Engineering, ETH Zurich, 4058 Basel, Switzerland.
| | - Vanni Doffini
- Department of Chemistry, University of Basel, 4058 Basel, Switzerland.,Department of Biosystems Science and Engineering, ETH Zurich, 4058 Basel, Switzerland.
| | - Jaime Fernández de Santaella
- Department of Chemistry, University of Basel, 4058 Basel, Switzerland.,Department of Biosystems Science and Engineering, ETH Zurich, 4058 Basel, Switzerland.
| | - Michael A Nash
- Department of Chemistry, University of Basel, 4058 Basel, Switzerland.,Department of Biosystems Science and Engineering, ETH Zurich, 4058 Basel, Switzerland.
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8
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González S, Ad O, Shah B, Zhang Z, Zhang X, Chatterjee A, Schepartz A. Genetic Code Expansion in the Engineered Organism Vmax X2: High Yield and Exceptional Fidelity. ACS CENTRAL SCIENCE 2021; 7:1500-1507. [PMID: 34584951 PMCID: PMC8461772 DOI: 10.1021/acscentsci.1c00499] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2021] [Indexed: 05/05/2023]
Abstract
We report that the recently introduced commercial strain of Vibrio natriegens (Vmax X2) supports robust unnatural amino acid mutagenesis, generating exceptional yields of soluble protein containing up to 5 noncanonical α-amino acids (ncAA). The isolated yields of ncAA-containing superfolder green fluorescent protein (sfGFP) expressed in Vmax X2 are up to 25-fold higher than those achieved using commercial expression strains (Top10 and BL21) and more than 10-fold higher than those achieved using two different genomically recodedEscherichia colistrains that lack endogenous UAG stop codons and release factor 1 and have been optimized for improved fitness and preferred growth temperature (C321.ΔA.opt and C321.ΔA.exp). In addition to higher yields of soluble protein, Vmax X2 cells also generate proteins with significantly lower levels of misincorporated natural α-amino acids at the UAG-programmed position, especially in cases where the ncAA is a moderate substrate for the chosen orthogonal aminoacyl tRNA synthetase (aaRS). This increase in fidelity implies that the use of Vmax X2 cells as the expression host can obviate the need for time-consuming directed evolution experiments to improve the selectivity of an aaRS toward highly desired but suboptimal ncAA substrates.
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Affiliation(s)
| | - Omer Ad
- Department
of Chemistry, Yale University, New Haven, Connecticut 06511, United States
| | - Bhavana Shah
- Process
Development, Attribute Sciences, Amgen Inc., Thousand Oaks, California 91320, United States
| | - Zhongqi Zhang
- Process
Development, Attribute Sciences, Amgen Inc., Thousand Oaks, California 91320, United States
| | - Xizi Zhang
- Department
of Chemistry, University of California, Berkeley, California 94720, United States
| | - Abhishek Chatterjee
- Department
of Chemistry, Boston College, Chestnut Hill, Massachusetts 02467, United States
| | - Alanna Schepartz
- Department
of Chemistry, University of California, Berkeley, California 94720, United States
- Department
of Molecular and Cellular Biology, University
of California, Berkeley, California 94720, United States
- California
Institute for Quantitative Biosciences (QB3), University of California, Berkeley, California 94720, United States
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9
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Chung CZ, Krahn N, Crnković A, Söll D. Intein-based Design Expands Diversity of Selenocysteine Reporters. J Mol Biol 2021; 434:167199. [PMID: 34411545 PMCID: PMC8847544 DOI: 10.1016/j.jmb.2021.167199] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 07/28/2021] [Accepted: 08/04/2021] [Indexed: 12/27/2022]
Abstract
The presence of selenocysteine in a protein confers many unique properties that make the production of recombinant selenoproteins desirable. Targeted incorporation of Sec into a protein of choice is possible by exploiting elongation factor Tu-dependent reassignment of UAG codons, a strategy that has been continuously improved by a variety of means. Improving selenoprotein yield by directed evolution requires selection and screening markers that are titratable, have a high dynamic range, enable high-throughput screening, and can discriminate against nonspecific UAG decoding. Current screening techniques are limited to a handful of reporters where a cysteine (Cys) or Sec residue normally affords activity. Unfortunately, these existing Cys/Sec-dependent reporters lack the dynamic range of more ubiquitous reporters or suffer from other limitations. Here we present a versatile strategy to adapt established reporters for specific Sec incorporation. Inteins are intervening polypeptides that splice themselves from the precursor protein in an autocatalytic splicing reaction. Using an intein that relies exclusively on Sec for splicing, we show that this intein cassette can be placed in-frame within selection and screening markers, affording reporter activity only upon successful intein splicing. Furthermore, because functional splicing can only occur when a catalytic Sec is present, the amount of synthesized reporter directly measures UAG-directed Sec incorporation. Importantly, we show that results obtained with intein-containing reporters are comparable to the Sec incorporation levels determined by mass spectrometry of isolated recombinant selenoproteins. This result validates the use of these intein-containing reporters to screen for evolved components of a translation system yielding increased selenoprotein amounts.
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Affiliation(s)
- Christina Z Chung
- Department of Molecular Biophysics and Biochemistry, Yale University, 266 Whitney Avenue, New Haven, CT 06511, USA.
| | - Natalie Krahn
- Department of Molecular Biophysics and Biochemistry, Yale University, 266 Whitney Avenue, New Haven, CT 06511, USA.
| | - Ana Crnković
- Department of Molecular Biophysics and Biochemistry, Yale University, 266 Whitney Avenue, New Haven, CT 06511, USA.
| | - Dieter Söll
- Department of Molecular Biophysics and Biochemistry, Yale University, 266 Whitney Avenue, New Haven, CT 06511, USA; Department of Chemistry, Yale University, 225 Prospect Street, New Haven, CT 06511, USA.
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10
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Schwark DG, Schmitt MA, Fisk JD. Directed Evolution of the Methanosarcina barkeri Pyrrolysyl tRNA/aminoacyl tRNA Synthetase Pair for Rapid Evaluation of Sense Codon Reassignment Potential. Int J Mol Sci 2021; 22:E895. [PMID: 33477414 PMCID: PMC7830368 DOI: 10.3390/ijms22020895] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 01/10/2021] [Accepted: 01/12/2021] [Indexed: 12/20/2022] Open
Abstract
Genetic code expansion has largely focused on the reassignment of amber stop codons to insert single copies of non-canonical amino acids (ncAAs) into proteins. Increasing effort has been directed at employing the set of aminoacyl tRNA synthetase (aaRS) variants previously evolved for amber suppression to incorporate multiple copies of ncAAs in response to sense codons in Escherichia coli. Predicting which sense codons are most amenable to reassignment and which orthogonal translation machinery is best suited to each codon is challenging. This manuscript describes the directed evolution of a new, highly efficient variant of the Methanosarcina barkeri pyrrolysyl orthogonal tRNA/aaRS pair that activates and incorporates tyrosine. The evolved M. barkeri tRNA/aaRS pair reprograms the amber stop codon with 98.1 ± 3.6% efficiency in E. coli DH10B, rivaling the efficiency of the wild-type tyrosine-incorporating Methanocaldococcus jannaschii orthogonal pair. The new orthogonal pair is deployed for the rapid evaluation of sense codon reassignment potential using our previously developed fluorescence-based screen. Measurements of sense codon reassignment efficiencies with the evolved M. barkeri machinery are compared with related measurements employing the M. jannaschii orthogonal pair system. Importantly, we observe different patterns of sense codon reassignment efficiency for the M. jannaschii tyrosyl and M. barkeri pyrrolysyl systems, suggesting that particular codons will be better suited to reassignment by different orthogonal pairs. A broad evaluation of sense codon reassignment efficiencies to tyrosine with the M. barkeri system will highlight the most promising positions at which the M. barkeri orthogonal pair may infiltrate the E. coli genetic code.
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Affiliation(s)
| | | | - John D. Fisk
- Department of Chemistry, University of Colorado Denver, Campus Box 194, P.O. Box 173364, Denver, CO 80217-3364, USA; (D.G.S.); (M.A.S.)
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11
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Galindo Casas M, Stargardt P, Mairhofer J, Wiltschi B. Decoupling Protein Production from Cell Growth Enhances the Site-Specific Incorporation of Noncanonical Amino Acids in E. coli. ACS Synth Biol 2020; 9:3052-3066. [PMID: 33150786 DOI: 10.1021/acssynbio.0c00298] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The site-specific incorporation of noncanonical amino acids (ncAAs) into proteins by amber stop codon suppression has become a routine method in academic laboratories. This approach requires an amber suppressor tRNACUA to read the amber codon and an aminoacyl-tRNA synthetase to charge the tRNACUA with the ncAA. However, a major drawback is the low yield of the mutant protein in comparison to the wild type. This effect primarily results from the competition of release factor 1 with the charged suppressor tRNACUA for the amber codon at the A-site of the ribosome. A number of laboratories have attempted to improve the incorporation efficiency of ncAAs with moderate results. We aimed at increasing the efficiency to produce high yields of ncAA-functionalized proteins in a scalable setting for industrial application. To do this, we inserted an ncAA into the enhanced green fluorescent protein and an antibody mimetic molecule using an industrial E. coli strain, which produces recombinant proteins independent of cell growth. The controlled decoupling of recombinant protein production from cell growth considerably increased the incorporation of the ncAA, producing substantially higher protein yields versus the reference E. coli strain BL21(DE3). The target proteins were expressed at high levels, and the ncAA was efficiently incorporated with excellent fidelity while the protein function was preserved.
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Affiliation(s)
- Meritxell Galindo Casas
- acib − Austrian Center of Industrial Biotechnology, 8010 Graz, Austria
- Institute of Molecular Biotechnology, Graz University of Technology, 8010 Graz, Austria
| | | | | | - Birgit Wiltschi
- acib − Austrian Center of Industrial Biotechnology, 8010 Graz, Austria
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12
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Cui Z, Johnston WA, Alexandrov K. Cell-Free Approach for Non-canonical Amino Acids Incorporation Into Polypeptides. Front Bioeng Biotechnol 2020; 8:1031. [PMID: 33117774 PMCID: PMC7550873 DOI: 10.3389/fbioe.2020.01031] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Accepted: 08/07/2020] [Indexed: 12/12/2022] Open
Abstract
Synthetic biology holds promise to revolutionize the life sciences and biomedicine via expansion of macromolecular diversity outside the natural chemical space. Use of non-canonical amino acids (ncAAs) via codon reassignment has found diverse applications in protein structure and interaction analysis, introduction of post-translational modifications, production of constrained peptides, antibody-drug conjugates, and novel enzymes. However, simultaneously encoding multiple ncAAs in vivo requires complex engineering and is sometimes restricted by the cell's poor uptake of ncAAs. In contrast the open nature of cell-free protein synthesis systems offers much greater freedom for manipulation and repurposing of the biosynthetic machinery by controlling the level and identity of translational components and reagents, and allows simultaneous incorporation of multiple ncAAs with non-canonical side chains and even backbones (N-methyl, D-, β-amino acids, α-hydroxy acids etc.). This review focuses on the two most used Escherichia coli-based cell-free protein synthesis systems; cell extract- and PURE-based systems. The former is a biological mixture with >500 proteins, while the latter consists of 38 individually purified biomolecules. We delineate compositions of these two systems and discuss their respective advantages and applications. Also, we dissect the translational components required for ncAA incorporation and compile lists of ncAAs that can be incorporated into polypeptides via different acylation approaches. We highlight the recent progress in using unnatural nucleobase pairs to increase the repertoire of orthogonal codons, as well as using tRNA-specific ribozymes for in situ acylation. We summarize advances in engineering of translational machinery such as tRNAs, aminoacyl-tRNA synthetases, elongation factors, and ribosomes to achieve efficient incorporation of structurally challenging ncAAs. We note that, many engineered components of biosynthetic machinery are developed for the use in vivo but are equally applicable to the in vitro systems. These are included in the review to provide a comprehensive overview for ncAA incorporation and offer new insights for the future development in cell-free systems. Finally, we highlight the exciting progress in the genomic engineering, resulting in E. coli strains free of amber and some redundant sense codons. These strains can be used for preparation of cell extracts offering multiple reassignment options.
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Affiliation(s)
- Zhenling Cui
- Synthetic Biology Laboratory, School of Biology and Environmental Science, Queensland University of Technology, Brisbane, QLD, Australia
| | - Wayne A Johnston
- Synthetic Biology Laboratory, School of Biology and Environmental Science, Queensland University of Technology, Brisbane, QLD, Australia
| | - Kirill Alexandrov
- Synthetic Biology Laboratory, School of Biology and Environmental Science, Queensland University of Technology, Brisbane, QLD, Australia
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13
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Abstract
Within the broad field of synthetic biology, genetic code expansion (GCE) techniques enable creation of proteins with an expanded set of amino acids. This may be invaluable for applications in therapeutics, bioremediation, and biocatalysis. Central to GCE are aminoacyl-tRNA synthetases (aaRSs) as they link a non-canonical amino acid (ncAA) to their cognate tRNA, allowing ncAA incorporation into proteins on the ribosome. The ncAA-acylating aaRSs and their tRNAs should not cross-react with 20 natural aaRSs and tRNAs in the host, i.e., they need to function as an orthogonal translating system. All current orthogonal aaRS•tRNA pairs have been engineered from naturally occurring molecules to change the aaRS's amino acid specificity or assign the tRNA to a liberated codon of choice. Here we discuss the importance of orthogonality in GCE, laboratory techniques employed to create designer aaRSs and tRNAs, and provide an overview of orthogonal aaRS•tRNA pairs for GCE purposes.
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Affiliation(s)
- Natalie Krahn
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, United States
| | - Jeffery M Tharp
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, United States
| | - Ana Crnković
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, United States
| | - Dieter Söll
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, United States.
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14
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Pérez-Mejías G, Velázquez-Cruz A, Guerra-Castellano A, Baños-Jaime B, Díaz-Quintana A, González-Arzola K, Ángel De la Rosa M, Díaz-Moreno I. Exploring protein phosphorylation by combining computational approaches and biochemical methods. Comput Struct Biotechnol J 2020; 18:1852-1863. [PMID: 32728408 PMCID: PMC7369424 DOI: 10.1016/j.csbj.2020.06.043] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 06/29/2020] [Accepted: 06/30/2020] [Indexed: 12/14/2022] Open
Abstract
Post-translational modifications of proteins expand their functional diversity, regulating the response of cells to a variety of stimuli. Among these modifications, phosphorylation is the most ubiquitous and plays a prominent role in cell signaling. The addition of a phosphate often affects the function of a protein by altering its structure and dynamics. However, these alterations are often difficult to study and the functional and structural implications remain unresolved. New approaches are emerging to overcome common obstacles related to the production and manipulation of these samples. Here, we summarize the available methods for phosphoprotein purification and phosphomimetic engineering, highlighting the advantages and disadvantages of each. We propose a general workflow for protein phosphorylation analysis combining computational and biochemical approaches, building on recent advances that enable user-friendly and easy-to-access Molecular Dynamics simulations. We hope this innovative workflow will inform the best experimental approach to explore such post-translational modifications. We have applied this workflow to two different human protein models: the hemeprotein cytochrome c and the RNA binding protein HuR. Our results illustrate the usefulness of Molecular Dynamics as a decision-making tool to design the most appropriate phosphomimetic variant.
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Affiliation(s)
- Gonzalo Pérez-Mejías
- Instituto de Investigaciones Químicas (IIQ), Centro de Investigaciones Científicas Isla de la Cartuja (cicCartuja), Universidad de Sevilla, Consejo Superior de Investigaciones Científicas (CSIC), Avda., Américo Vespucio 49, Sevilla 41092, Spain
| | - Alejandro Velázquez-Cruz
- Instituto de Investigaciones Químicas (IIQ), Centro de Investigaciones Científicas Isla de la Cartuja (cicCartuja), Universidad de Sevilla, Consejo Superior de Investigaciones Científicas (CSIC), Avda., Américo Vespucio 49, Sevilla 41092, Spain
| | - Alejandra Guerra-Castellano
- Instituto de Investigaciones Químicas (IIQ), Centro de Investigaciones Científicas Isla de la Cartuja (cicCartuja), Universidad de Sevilla, Consejo Superior de Investigaciones Científicas (CSIC), Avda., Américo Vespucio 49, Sevilla 41092, Spain
| | - Blanca Baños-Jaime
- Instituto de Investigaciones Químicas (IIQ), Centro de Investigaciones Científicas Isla de la Cartuja (cicCartuja), Universidad de Sevilla, Consejo Superior de Investigaciones Científicas (CSIC), Avda., Américo Vespucio 49, Sevilla 41092, Spain
| | - Antonio Díaz-Quintana
- Instituto de Investigaciones Químicas (IIQ), Centro de Investigaciones Científicas Isla de la Cartuja (cicCartuja), Universidad de Sevilla, Consejo Superior de Investigaciones Científicas (CSIC), Avda., Américo Vespucio 49, Sevilla 41092, Spain
| | - Katiuska González-Arzola
- Instituto de Investigaciones Químicas (IIQ), Centro de Investigaciones Científicas Isla de la Cartuja (cicCartuja), Universidad de Sevilla, Consejo Superior de Investigaciones Científicas (CSIC), Avda., Américo Vespucio 49, Sevilla 41092, Spain
| | - Miguel Ángel De la Rosa
- Instituto de Investigaciones Químicas (IIQ), Centro de Investigaciones Científicas Isla de la Cartuja (cicCartuja), Universidad de Sevilla, Consejo Superior de Investigaciones Científicas (CSIC), Avda., Américo Vespucio 49, Sevilla 41092, Spain
| | - Irene Díaz-Moreno
- Instituto de Investigaciones Químicas (IIQ), Centro de Investigaciones Científicas Isla de la Cartuja (cicCartuja), Universidad de Sevilla, Consejo Superior de Investigaciones Científicas (CSIC), Avda., Américo Vespucio 49, Sevilla 41092, Spain
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15
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Potts KA, Stieglitz JT, Lei M, Van Deventer JA. Reporter system architecture affects measurements of noncanonical amino acid incorporation efficiency and fidelity. MOLECULAR SYSTEMS DESIGN & ENGINEERING 2020; 5:573-588. [PMID: 33791108 PMCID: PMC8009230 DOI: 10.1039/c9me00107g] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The ability to genetically encode noncanonical amino acids (ncAAs) within proteins supports a growing number of applications ranging from fundamental biological studies to enhancing the properties of biological therapeutics. Currently, our quantitative understanding of ncAA incorporation systems is confounded by the diverse set of characterization and analysis approaches used to quantify ncAA incorporation events. While several effective reporter systems support such measurements, it is not clear how quantitative results from different reporters relate to one another, or which details influence measurements most strongly. Here, we evaluate the quantitative performance of single-fluorescent protein reporters, dual-fluorescent protein reporters, and cell surface-displayed protein reporters of ncAA insertion in response to the TAG (amber) codon in yeast. While different reporters support varying levels of apparent readthrough efficiencies, flow cytometry-based evaluations with dual reporters yielded measurements exhibiting consistent quantitative trends and precision across all evaluated conditions. Further investigations of dual-fluorescent protein reporter architecture revealed that quantitative outputs are influenced by stop codon location and N- and C-terminal fluorescent protein identity. Both dual-fluorescent protein reporters and a "drop-in" version of yeast display support quantification of ncAA incorporation in several single-gene knockout strains, revealing strains that enhance ncAA incorporation efficiency without compromising fidelity. Our studies reveal critical details regarding reporter system performance in yeast and how to effectively deploy such reporters. These findings have substantial implications for how to engineer ncAA incorporation systems-and protein translation apparatuses-to better accommodate alternative genetic codes for expanding the chemical diversity of biosynthesized proteins.
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Affiliation(s)
- K A Potts
- Chemical and Biological Engineering Department, Tufts University, Medford, Massachusetts 02155, United States
| | - J T Stieglitz
- Chemical and Biological Engineering Department, Tufts University, Medford, Massachusetts 02155, United States
| | - M Lei
- Chemical and Biological Engineering Department, Tufts University, Medford, Massachusetts 02155, United States
| | - J A Van Deventer
- Chemical and Biological Engineering Department, Tufts University, Medford, Massachusetts 02155, United States
- Biomedical Engineering Department, Tufts University, Medford, Massachusetts 02155, United States
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16
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Markel U, Essani KD, Besirlioglu V, Schiffels J, Streit WR, Schwaneberg U. Advances in ultrahigh-throughput screening for directed enzyme evolution. Chem Soc Rev 2020; 49:233-262. [PMID: 31815263 DOI: 10.1039/c8cs00981c] [Citation(s) in RCA: 142] [Impact Index Per Article: 35.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Enzymes are versatile catalysts and their synthetic potential has been recognized for a long time. In order to exploit their full potential, enzymes often need to be re-engineered or optimized for a given application. (Semi-) rational design has emerged as a powerful means to engineer proteins, but requires detailed knowledge about structure function relationships. In turn, directed evolution methodologies, which consist of iterative rounds of diversity generation and screening, can improve an enzyme's properties with virtually no structural knowledge. Current diversity generation methods grant us access to a vast sequence space (libraries of >1012 enzyme variants) that may hide yet unexplored catalytic activities and selectivity. However, the time investment for conventional agar plate or microtiter plate-based screening assays represents a major bottleneck in directed evolution and limits the improvements that are obtainable in reasonable time. Ultrahigh-throughput screening (uHTS) methods dramatically increase the number of screening events per time, which is crucial to speed up biocatalyst design, and to widen our knowledge about sequence function relationships. In this review, we summarize recent advances in uHTS for directed enzyme evolution. We shed light on the importance of compartmentalization to preserve the essential link between genotype and phenotype and discuss how cells and biomimetic compartments can be applied to serve this function. Finally, we discuss how uHTS can inspire novel functional metagenomics approaches to identify natural biocatalysts for novel chemical transformations.
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Affiliation(s)
- Ulrich Markel
- Institute of Biotechnology, RWTH Aachen University, Worringer Weg 3, 52074 Aachen, Germany.
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17
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Crnković A, Vargas-Rodriguez O, Söll D. Plasticity and Constraints of tRNA Aminoacylation Define Directed Evolution of Aminoacyl-tRNA Synthetases. Int J Mol Sci 2019; 20:ijms20092294. [PMID: 31075874 PMCID: PMC6540133 DOI: 10.3390/ijms20092294] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 04/29/2019] [Accepted: 05/07/2019] [Indexed: 02/07/2023] Open
Abstract
Genetic incorporation of noncanonical amino acids (ncAAs) has become a powerful tool to enhance existing functions or introduce new ones into proteins through expanded chemistry. This technology relies on the process of nonsense suppression, which is made possible by directing aminoacyl-tRNA synthetases (aaRSs) to attach an ncAA onto a cognate suppressor tRNA. However, different mechanisms govern aaRS specificity toward its natural amino acid (AA) substrate and hinder the engineering of aaRSs for applications beyond the incorporation of a single l-α-AA. Directed evolution of aaRSs therefore faces two interlinked challenges: the removal of the affinity for cognate AA and improvement of ncAA acylation. Here we review aspects of AA recognition that directly influence the feasibility and success of aaRS engineering toward d- and β-AAs incorporation into proteins in vivo. Emerging directed evolution methods are described and evaluated on the basis of aaRS active site plasticity and its inherent constraints.
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Affiliation(s)
- Ana Crnković
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA.
| | - Oscar Vargas-Rodriguez
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA.
| | - Dieter Söll
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA.
- Department of Chemistry, Yale University, New Haven, CT 06520, USA.
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