1
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Schmitt MA, Tittle JM, Fisk JD. Codon decoding by orthogonal tRNAs interrogates the in vivo preferences of unmodified adenosine in the wobble position. Front Genet 2024; 15:1386299. [PMID: 38706795 PMCID: PMC11066159 DOI: 10.3389/fgene.2024.1386299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Accepted: 03/30/2024] [Indexed: 05/07/2024] Open
Abstract
The in vivo codon decoding preferences of tRNAs with an authentic adenosine residue at position 34 of the anticodon, the wobble position, are largely unexplored because very few unmodified A34 tRNA genes exist across the three domains of life. The expanded wobble rules suggest that unmodified adenosine pairs most strongly with uracil, modestly with cytosine, and weakly with guanosine and adenosine. Inosine, a modified adenosine, on the other hand, pairs strongly with both uracil and cytosine and to a lesser extent adenosine. Orthogonal pair directed sense codon reassignment experiments offer a tool with which to interrogate the translational activity of A34 tRNAs because the introduced tRNA can be engineered with any anticodon. Our fluorescence-based screen utilizes the absolute requirement of tyrosine at position 66 of superfolder GFP for autocatalytic fluorophore formation. The introduced orthogonal tRNA competes with the endogenous translation machinery to incorporate tyrosine in response to a codon typically assigned another meaning in the genetic code. We evaluated the codon reassignment efficiencies of 15 of the 16 possible orthogonal tRNAs with A34 anticodons. We examined the Sanger sequencing chromatograms for cDNAs from each of the reverse transcribed tRNAs for evidence of inosine modification. Despite several A34 tRNAs decoding closely-related C-ending codons, partial inosine modification was detected for only three species. These experiments employ a single tRNA body with a single attached amino acid to interrogate the behavior of different anticodons in the background of in vivo E. coli translation and greatly expand the set of experimental measurements of the in vivo function of A34 tRNAs in translation. For the most part, unmodified A34 tRNAs largely pair with only U3 codons as the original wobble rules suggest. In instances with GC pairs in the first two codon positions, unmodified A34 tRNAs decode the C- and G-ending codons as well as the expected U-ending codon. These observations support the "two-out-of-three" and "strong and weak" codon hypotheses.
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Affiliation(s)
| | | | - John D. Fisk
- Department of Chemistry, University of Colorado Denver, Denver, CO, United States
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2
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Terasawa K, Seike T, Sakamoto K, Ohtake K, Terada T, Iwata T, Watabe T, Yokoyama S, Hara‐Yokoyama M. Site-specific photo-crosslinking/cleavage for protein-protein interface identification reveals oligomeric assembly of lysosomal-associated membrane protein type 2A in mammalian cells. Protein Sci 2023; 32:e4823. [PMID: 37906694 PMCID: PMC10659947 DOI: 10.1002/pro.4823] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 10/16/2023] [Accepted: 10/21/2023] [Indexed: 11/02/2023]
Abstract
Genetic code expansion enables site-specific photo-crosslinking by introducing photo-reactive non-canonical amino acids into proteins at defined positions during translation. This technology is widely used for analyzing protein-protein interactions and is applicable in mammalian cells. However, the identification of the crosslinked region still remains challenging. Here, we developed a new method to identify the crosslinked region by pre-installing a site-specific cleavage site, an α-hydroxy acid (Nε -allyloxycarbonyl-α-hydroxyl-l-lysine acid, AllocLys-OH), into the target protein. Alkaline treatment cleaves the crosslinked complex at the position of the α-hydroxy acid residue and thus helps to identify which side of the cleavage site, either closer to the N-terminus or C-terminus, the crosslinked site is located within the target protein. A series of AllocLys-OH introductions narrows down the crosslinked region. By applying this method, we identified the crosslinked regions in lysosomal-associated membrane protein type 2A (LAMP2A), a receptor of chaperone-mediated autophagy, in mammalian cells. The results suggested that at least two interfaces are involved in the homophilic interaction, which requires a trimeric or higher oligomeric assembly of adjacent LAMP2A molecules. Thus, the combination of site-specific crosslinking and site-specific cleavage promises to be useful for revealing binding interfaces and protein complex geometries.
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Affiliation(s)
- Kazue Terasawa
- Department of Biochemistry, Graduate School of Medical and Dental SciencesTokyo Medical and Dental University (TMDU)TokyoJapan
- LiberoThera Co., Ltd.Chuo‐kuJapan
| | - Tatsuro Seike
- Department of Periodontology, Graduate School of Medical and Dental SciencesTokyo Medical and Dental University (TMDU)TokyoJapan
| | - Kensaku Sakamoto
- Laboratory for Nonnatural Amino Acid TechnologyRIKEN Center for Biosystems Dynamics ResearchYokohamaJapan
- Department of Drug Target Protein ResearchShinshu University School of MedicineNaganoJapan
| | - Kazumasa Ohtake
- Laboratory for Nonnatural Amino Acid TechnologyRIKEN Center for Biosystems Dynamics ResearchYokohamaJapan
- Department of Electrical Engineering and BioscienceWaseda UniversityTokyoJapan
| | - Tohru Terada
- Department of Biotechnology, Graduate School of Agricultural and Life SciencesThe University of TokyoTokyoJapan
| | - Takanori Iwata
- Department of Periodontology, Graduate School of Medical and Dental SciencesTokyo Medical and Dental University (TMDU)TokyoJapan
| | - Tetsuro Watabe
- Department of Biochemistry, Graduate School of Medical and Dental SciencesTokyo Medical and Dental University (TMDU)TokyoJapan
| | - Shigeyuki Yokoyama
- Department of Drug Target Protein ResearchShinshu University School of MedicineNaganoJapan
- Laboratory for Protein Function and Structural BiologyRIKEN Cluster for Science, Technology and Innovation HubYokohamaJapan
- Department of Structural Biology and Biochemistry, Graduate School of Medical and Dental SciencesTokyo Medical and Dental University (TMDU)TokyoJapan
| | - Miki Hara‐Yokoyama
- Department of Biochemistry, Graduate School of Medical and Dental SciencesTokyo Medical and Dental University (TMDU)TokyoJapan
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3
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Xu C, Zou Q, Tian J, Li M, Xing B, Gong J, Wang J, Huo YX, Guo S. Simplified Construction of Engineered Bacillus subtilis Host for Improved Expression of Proteins Harboring Noncanonical Amino Acids. ACS Synth Biol 2023; 12:583-595. [PMID: 36653175 DOI: 10.1021/acssynbio.2c00604] [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: 01/20/2023]
Abstract
The UAG-based genetic code expansion (GCE) enables site-specific incorporation of noncanonical amino acids (ncAAs) harboring novel chemical functionalities in specific target proteins. However, most GCE studies were done in several whole-genome engineered chassis cells whose hundreds of UAG stop codons were systematically edited to UAA to avoid readthrough in protein synthesis in the presence of GCE. The huge workload of removing all UAG limited the application of GCE in other microbial cell factories (MCF) such as Bacillus subtilis, which has 607 genes ended with UAG among its 4245 coding genes. Although the 257 essential genes count only 6.1% of the genes in B. subtilis, they transcribe 12.2% of the mRNAs and express 52.1% of the proteins under the exponential phase. Here, we engineered a strain named Bs-22 in which all 22 engineerable UAG stop codons in essential genes were edited to UAA via CRISPR/Cas9-mediated multiple-site engineering to minimize the negative effect of GCE on the expression of essential genes. Besides the process of constructing GCE-compatible B. subtilis was systematically optimized. Compared with wild-type B. subtilis (Bs-WT), the fluorescence signal of the eGFP expression could enhance 2.25-fold in Bs-22, and the production of protein tsPurple containing l-(7-hydroxycoumarin-4-yl) ethylglycine (Cou) was increased 2.31-fold in Bs-22. We verified that all purified tsPurple proteins from Bs-22 contained Cou, indicating the excellent fidelity of the strategy. This proof-of-concept study reported efficient overexpression of ncAA-rich proteins in MCF with minimized engineering, shedding new light on solving the trade-off between efficiency and workload.
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Affiliation(s)
- Changgeng Xu
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, 5 South Zhongguancun Street, Haidian District, 100081 Beijing, China
| | - Qin Zou
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, 5 South Zhongguancun Street, Haidian District, 100081 Beijing, China.,Beijing Institute of Technology (Tangshan) Translational Research Center, Tangshan Port Economic Development Zone, 063611 Hebei, China
| | - Jiheng Tian
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, 5 South Zhongguancun Street, Haidian District, 100081 Beijing, China
| | - Mengyuan Li
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, 5 South Zhongguancun Street, Haidian District, 100081 Beijing, China
| | - Baowen Xing
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, 5 South Zhongguancun Street, Haidian District, 100081 Beijing, China
| | - Julia Gong
- Marymount High School, Los Angeles, California 10643, United States
| | - Jiangyun Wang
- Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Chaoyang District, 100101 Beijing, China
| | - Yi-Xin Huo
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, 5 South Zhongguancun Street, Haidian District, 100081 Beijing, China.,Beijing Institute of Technology (Tangshan) Translational Research Center, Tangshan Port Economic Development Zone, 063611 Hebei, China
| | - Shuyuan Guo
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, 5 South Zhongguancun Street, Haidian District, 100081 Beijing, China
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4
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Sisila V, Indhu M, Radhakrishnan J, Ayyadurai N. Building biomaterials through genetic code expansion. Trends Biotechnol 2023; 41:165-183. [PMID: 35908989 DOI: 10.1016/j.tibtech.2022.07.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 06/30/2022] [Accepted: 07/08/2022] [Indexed: 01/24/2023]
Abstract
Genetic code expansion (GCE) enables directed incorporation of noncoded amino acids (NCAAs) and unnatural amino acids (UNAAs) into the active core that confers dedicated structure and function to engineered proteins. Many protein biomaterials are tandem repeats that intrinsically include NCAAs generated through post-translational modifications (PTMs) to execute assigned functions. Conventional genetic engineering approaches using prokaryotic systems have limited ability to biosynthesize functionally active biomaterials with NCAAs/UNAAs. Codon suppression and reassignment introduce NCAAs/UNAAs globally, allowing engineered proteins to be redesigned to mimic natural matrix-cell interactions for tissue engineering. Expanding the genetic code enables the engineering of biomaterials with catechols - growth factor mimetics that modulate cell-matrix interactions - thereby facilitating tissue-specific expression of genes and proteins. This method of protein engineering shows promise in achieving tissue-informed, tissue-compliant tunable biomaterials.
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Affiliation(s)
- Valappil Sisila
- Department of Biochemistry and Biotechnology, Council of Scientific and Industrial Research (CSIR) Central Leather Research Institute (CLRI), Chennai, Tamil Nadu 600020, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201 002, India
| | - Mohan Indhu
- Department of Biochemistry and Biotechnology, Council of Scientific and Industrial Research (CSIR) Central Leather Research Institute (CLRI), Chennai, Tamil Nadu 600020, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201 002, India
| | - Janani Radhakrishnan
- Department of Biochemistry and Biotechnology, Council of Scientific and Industrial Research (CSIR) Central Leather Research Institute (CLRI), Chennai, Tamil Nadu 600020, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201 002, India.
| | - Niraikulam Ayyadurai
- Department of Biochemistry and Biotechnology, Council of Scientific and Industrial Research (CSIR) Central Leather Research Institute (CLRI), Chennai, Tamil Nadu 600020, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201 002, India.
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5
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Kimoto M, Hirao I. Genetic Code Engineering by Natural and Unnatural Base Pair Systems for the Site-Specific Incorporation of Non-Standard Amino Acids Into Proteins. Front Mol Biosci 2022; 9:851646. [PMID: 35685243 PMCID: PMC9171071 DOI: 10.3389/fmolb.2022.851646] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 04/25/2022] [Indexed: 12/21/2022] Open
Abstract
Amino acid sequences of proteins are encoded in nucleic acids composed of four letters, A, G, C, and T(U). However, this four-letter alphabet coding system limits further functionalities of proteins by the twenty letters of amino acids. If we expand the genetic code or develop alternative codes, we could create novel biological systems and biotechnologies by the site-specific incorporation of non-standard amino acids (or unnatural amino acids, unAAs) into proteins. To this end, new codons and their complementary anticodons are required for unAAs. In this review, we introduce the current status of methods to incorporate new amino acids into proteins by in vitro and in vivo translation systems, by focusing on the creation of new codon-anticodon interactions, including unnatural base pair systems for genetic alphabet expansion.
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Affiliation(s)
| | - Ichiro Hirao
- *Correspondence: Michiko Kimoto, ; Ichiro Hirao,
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6
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Biddle W, Schwark DG, Schmitt MA, Fisk JD. Directed Evolution Pipeline for the Improvement of Orthogonal Translation Machinery for Genetic Code Expansion at Sense Codons. Front Chem 2022; 10:815788. [PMID: 35252113 PMCID: PMC8891652 DOI: 10.3389/fchem.2022.815788] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 01/24/2022] [Indexed: 12/30/2022] Open
Abstract
The expansion of the genetic code beyond a single type of noncanonical amino acid (ncAA) is hindered by inefficient machinery for reassigning the meaning of sense codons. A major obstacle to using directed evolution to improve the efficiency of sense codon reassignment is that fractional sense codon reassignments lead to heterogeneous mixtures of full-length proteins with either a ncAA or a natural amino acid incorporated in response to the targeted codon. In stop codon suppression systems, missed incorporations lead to truncated proteins; improvements in activity may be inferred from increased protein yields or the production of downstream reporters. In sense codon reassignment, the heterogeneous proteins produced greatly complicate the development of screens for variants of the orthogonal machinery with improved activity. We describe the use of a previously-reported fluorescence-based screen for sense codon reassignment as the first step in a directed evolution workflow to improve the incorporation of a ncAA in response to the Arg AGG sense codon. We first screened a library with diversity introduced into both the orthogonal Methanocaldococcus jannaschii tyrosyl tRNA anticodon loop and the cognate aminoacyl tRNA synthetase (aaRS) anticodon binding domain for variants that improved incorporation of tyrosine in response to the AGG codon. The most efficient variants produced fluorescent proteins at levels indistinguishable from the E. coli translation machinery decoding tyrosine codons. Mutations to the M. jannaschii aaRS that were found to improve tyrosine incorporation were transplanted onto a M. jannaschii aaRS evolved for the incorporation of para-azidophenylalanine. Improved ncAA incorporation was evident using fluorescence- and mass-based reporters. The described workflow is generalizable and should enable the rapid tailoring of orthogonal machinery capable of activating diverse ncAAs to any sense codon target. We evaluated the selection based improvements of the orthogonal pair in a host genomically engineered for reduced target codon competition. Using this particular system for evaluation of arginine AGG codon reassignment, however, E. coli strains with genomes engineered to remove competing tRNAs did not outperform a standard laboratory E. coli strain in sense codon reassignment.
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7
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Lateef OM, Akintubosun MO, Olaoba OT, Samson SO, Adamczyk M. Making Sense of "Nonsense" and More: Challenges and Opportunities in the Genetic Code Expansion, in the World of tRNA Modifications. Int J Mol Sci 2022; 23:938. [PMID: 35055121 PMCID: PMC8779196 DOI: 10.3390/ijms23020938] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 01/10/2022] [Accepted: 01/12/2022] [Indexed: 01/09/2023] Open
Abstract
The evolutional development of the RNA translation process that leads to protein synthesis based on naturally occurring amino acids has its continuation via synthetic biology, the so-called rational bioengineering. Genetic code expansion (GCE) explores beyond the natural translational processes to further enhance the structural properties and augment the functionality of a wide range of proteins. Prokaryotic and eukaryotic ribosomal machinery have been proven to accept engineered tRNAs from orthogonal organisms to efficiently incorporate noncanonical amino acids (ncAAs) with rationally designed side chains. These side chains can be reactive or functional groups, which can be extensively utilized in biochemical, biophysical, and cellular studies. Genetic code extension offers the contingency of introducing more than one ncAA into protein through frameshift suppression, multi-site-specific incorporation of ncAAs, thereby increasing the vast number of possible applications. However, different mediating factors reduce the yield and efficiency of ncAA incorporation into synthetic proteins. In this review, we comment on the recent advancements in genetic code expansion to signify the relevance of systems biology in improving ncAA incorporation efficiency. We discuss the emerging impact of tRNA modifications and metabolism in protein design. We also provide examples of the latest successful accomplishments in synthetic protein therapeutics and show how codon expansion has been employed in various scientific and biotechnological applications.
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Affiliation(s)
- Olubodun Michael Lateef
- Faculty of Chemistry, Warsaw University of Technology, 00-664 Warsaw, Poland; (O.M.L.); (M.O.A.); (S.O.S.)
| | | | - Olamide Tosin Olaoba
- Laboratory of Functional and Structural Biochemistry, Federal University of Sao Carlos, Sao Carlos 13565-905, SP, Brazil;
| | - Sunday Ocholi Samson
- Faculty of Chemistry, Warsaw University of Technology, 00-664 Warsaw, Poland; (O.M.L.); (M.O.A.); (S.O.S.)
| | - Malgorzata Adamczyk
- Faculty of Chemistry, Warsaw University of Technology, 00-664 Warsaw, Poland; (O.M.L.); (M.O.A.); (S.O.S.)
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8
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Romesberg FE. Creation, Optimization, and Use of Semi-Synthetic Organisms that Store and Retrieve Increased Genetic Information. J Mol Biol 2021; 434:167331. [PMID: 34710400 DOI: 10.1016/j.jmb.2021.167331] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 10/18/2021] [Accepted: 10/20/2021] [Indexed: 12/18/2022]
Abstract
With few exceptions, natural proteins are built from only 20 canonical (proteogenic) amino acids which limits the functionality and accordingly the properties they can possess. Genetic code expansion, i.e. the creation of codons and the machinery needed to assign them to non-canonical amino acids (ncAAs), promises to enable the discovery of proteins with novel properties that are otherwise difficult or impossible to obtain. One approach to expanding the genetic code is to expand the genetic alphabet via the development of unnatural nucleotides that pair to form an unnatural base pair (UBP). Semi-synthetic organisms (SSOs), i.e. organisms that stably maintain the UBP, transcribe its component nucleotides into RNA, and use it to translate proteins, would have available to them new codons and the anticodons needed to assign them to ncAAs. This review summarizes the development of a family of UBPs, their use to create SSOs, and the optimization and application of the SSOs to produce candidate therapeutic proteins with improved properties that are now undergoing evaluation in clinical trials.
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9
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Zhou W, Deiters A. Chemogenetic and optogenetic control of post-translational modifications through genetic code expansion. Curr Opin Chem Biol 2021; 63:123-131. [PMID: 33845403 PMCID: PMC8384655 DOI: 10.1016/j.cbpa.2021.02.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 02/23/2021] [Accepted: 02/25/2021] [Indexed: 02/08/2023]
Abstract
Post-translational modifications (PTMs) of proteins extensively diversify the biological information flow from the genome to the proteome and thus have profound pathophysiological implications. Precise dissection of the regulatory networks of PTMs benefits from the ability to achieve conditional control through external optogenetic or chemogenetic triggers. Genetic code expansion provides a unique solution by allowing for site-specific installation of functionally masked unnatural amino acids (UAAs) into proteins, such as enzymes and enzyme substrates, rendering them inert until rapid activation through exposure to light or small molecules. Here, we summarize the most recent advances harnessing this methodology to study various forms of PTMs, as well as generalizable approaches to externally control nodes-of-interest in PTM networks.
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Affiliation(s)
- Wenyuan Zhou
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, 15260, USA
| | - Alexander Deiters
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, 15260, USA.
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10
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Tharp JM, Vargas-Rodriguez O, Schepartz A, Söll D. Genetic Encoding of Three Distinct Noncanonical Amino Acids Using Reprogrammed Initiator and Nonsense Codons. ACS Chem Biol 2021; 16:766-774. [PMID: 33723984 DOI: 10.1021/acschembio.1c00120] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
We recently described an orthogonal initiator tRNA (itRNATy2) that can initiate protein synthesis with noncanonical amino acids (ncAAs) in response to the UAG nonsense codon. Here, we report that a mutant of itRNATy2 (itRNATy2AUA) can efficiently initiate translation in response to the UAU tyrosine codon, giving rise to proteins with an ncAA at their N-terminus. We show that, in cells expressing itRNATy2AUA, UAU can function as a dual-use codon that selectively encodes ncAAs at the initiating position and predominantly tyrosine at elongating positions. Using itRNATy2AUA, in conjunction with its cognate tyrosyl-tRNA synthetase and two mutually orthogonal pyrrolysyl-tRNA synthetases, we demonstrate that UAU can be reassigned along with UAG or UAA to encode two distinct ncAAs in the same protein. Furthermore, by engineering the substrate specificity of one of the pyrrolysyl-tRNA synthetases, we developed a triply orthogonal system that enables simultaneous reassignment of UAU, UAG, and UAA to produce proteins containing three distinct ncAAs at precisely defined sites. To showcase the utility of this system, we produced proteins containing two or three ncAAs, with unique bioorthogonal functional groups, and demonstrate that these proteins can be separately modified with multiple fluorescent probes.
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11
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Manandhar M, Chun E, Romesberg FE. Genetic Code Expansion: Inception, Development, Commercialization. J Am Chem Soc 2021; 143:4859-4878. [DOI: 10.1021/jacs.0c11938] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Miglena Manandhar
- Synthorx, a Sanofi Company, La Jolla, California 92037, United States
| | - Eugene Chun
- Synthorx, a Sanofi Company, La Jolla, California 92037, United States
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12
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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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13
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Schwark DG, Schmitt MA, Biddle W, Fisk JD. The Influence of Competing tRNA Abundance on Translation: Quantifying the Efficiency of Sense Codon Reassignment at Rarely Used Codons. Chembiochem 2020; 21:2274-2286. [PMID: 32203635 DOI: 10.1002/cbic.202000052] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 03/12/2020] [Indexed: 11/07/2022]
Abstract
A quantitative understanding of how system composition and molecular properties conspire to determine the fidelity of translation is lacking. Our strategy directs an orthogonal tRNA to directly compete against endogenous tRNAs to decode individual targeted codons in a GFP reporter. Sets of directed sense codon reassignment measurements allow the isolation of particular factors contributing to translational fidelity. In this work, we isolated the effect of tRNA concentration on translational fidelity by evaluating reassignment of the 15 least commonly employed E. coli sense codons. Eight of the rarely used codons are reassigned with greater than 20 % efficiency. Both tRNA abundance and codon demand moderately inversely correlate with reassignment efficiency. Furthermore, the reassignment of rarely used codons does not appear to confer a fitness advantage relative to reassignment of other codons. These direct competition experiments also map potential targets for genetic code expansion. The isoleucine AUA codon is particularly attractive for the incorporation of noncanonical amino acids, with a nonoptimized reassignment efficiency of nearly 70 %.
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Affiliation(s)
- David G Schwark
- Department of Chemistry, University of Colorado Denver Campus Box 194, P.O. Box 173364, Denver, CO 80217-3364, USA
| | - Margaret A Schmitt
- Department of Chemistry, University of Colorado Denver Campus Box 194, P.O. Box 173364, Denver, CO 80217-3364, USA
| | - Wil Biddle
- Department of Chemistry, University of Colorado Denver Campus Box 194, P.O. Box 173364, Denver, CO 80217-3364, USA
| | - John D Fisk
- Department of Chemistry, University of Colorado Denver Campus Box 194, P.O. Box 173364, Denver, CO 80217-3364, USA
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14
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Cui Z, Wu Y, Mureev S, Alexandrov K. Oligonucleotide-mediated tRNA sequestration enables one-pot sense codon reassignment in vitro. Nucleic Acids Res 2019; 46:6387-6400. [PMID: 29846683 PMCID: PMC6158751 DOI: 10.1093/nar/gky365] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Accepted: 04/26/2018] [Indexed: 12/17/2022] Open
Abstract
Sense codon reassignment to unnatural amino acids (uAAs) represents a powerful approach for introducing novel properties into polypeptides. The main obstacle to this approach is competition between the native isoacceptor tRNA(s) and orthogonal tRNA(s) for the reassigned codon. While several chromatographic and enzymatic procedures for selective deactivation of tRNA isoacceptors in cell-free translation systems exist, they are complex and not scalable. We designed a set of tRNA antisense oligonucleotides composed of either deoxy-, ribo- or 2′-O-methyl ribonucleotides and tested their ability to efficiently complex tRNAs of choice. Methylated oligonucleotides targeting sequence between the anticodon and variable loop of tRNASerGCU displayed subnanomolar binding affinity with slow dissociation kinetics. Such oligonucleotides efficiently and selectively sequestered native tRNASerGCU directly in translation-competent Escherichia coli S30 lysate, thereby, abrogating its translational activity and liberating the AGU/AGC codons. Expression of eGFP protein from the template harboring a single reassignable AGU codon in tRNASerGCU-depleted E. coli lysate allowed its homogeneous modification with n-propargyl-l-lysine or p-azido-l-phenylalanine. The strategy developed here is generic, as demonstrated by sequestration of tRNAArgCCU isoacceptor in E. coli translation system. Furthermore, this method is likely to be species-independent and was successfully applied to the eukaryotic Leishmania tarentolae in vitro translation system. This approach represents a new direction in genetic code reassignment with numerous practical applications.
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Affiliation(s)
- Zhenling Cui
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Yue Wu
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Sergey Mureev
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Kirill Alexandrov
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD 4072, Australia.,Australian Institute for Bioengeneering and Nanotechnology, The University of Queensland, St Lucia, QLD 4072, Australia
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15
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Gao W, Cho E, Liu Y, Lu Y. Advances and Challenges in Cell-Free Incorporation of Unnatural Amino Acids Into Proteins. Front Pharmacol 2019; 10:611. [PMID: 31191324 PMCID: PMC6549004 DOI: 10.3389/fphar.2019.00611] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Accepted: 05/15/2019] [Indexed: 12/17/2022] Open
Abstract
Incorporation of unnatural amino acids (UNAAs) into proteins currently is an active biological research area for various fundamental and applied science. In this context, cell-free synthetic biology (CFSB) has been developed and recognized as a robust testing and biomanufacturing platform for highly efficient UNAA incorporation. It enables the orchestration of unnatural biological machinery toward an exclusive user-defined objective of unnatural protein synthesis. This review aims to overview the principles of cell-free unnatural protein synthesis (CFUPS) systems, their advantages, different UNAA incorporation approaches, and recent achievements. These have catalyzed cutting-edge research and diverse emerging applications. Especially, present challenges and future trends are focused and discussed. With the development of CFSB and the fusion with other advanced next-generation technologies, CFUPS systems would explicitly deliver their values for biopharmaceutical applications.
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Affiliation(s)
- Wei Gao
- Department of Chemical Engineering, Tsinghua University, Beijing, China
- College of Life Science, Shenyang Normal University, Shenyang, China
| | - Eunhee Cho
- Department of Chemical Engineering, Tsinghua University, Beijing, China
| | - Yingying Liu
- Department of Chemical Engineering, Tsinghua University, Beijing, China
- College of Life Science, Shenyang Normal University, Shenyang, China
| | - Yuan Lu
- Department of Chemical Engineering, Tsinghua University, Beijing, China
- Institute of Biochemical Engineering, Department of Chemical Engineering, Tsinghua University, Beijing, China
- Key Lab of Industrial Biocatalysis, Ministry of Education, Department of Chemical Engineering, Tsinghua University, Beijing, China
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16
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Pyrrolysyl-tRNA Synthetase with a Unique Architecture Enhances the Availability of Lysine Derivatives in Synthetic Genetic Codes. Molecules 2018; 23:molecules23102460. [PMID: 30261594 PMCID: PMC6222415 DOI: 10.3390/molecules23102460] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Revised: 09/25/2018] [Accepted: 09/25/2018] [Indexed: 11/16/2022] Open
Abstract
Genetic code expansion has largely relied on two types of the tRNA—aminoacyl-tRNA synthetase pairs. One involves pyrrolysyl-tRNA synthetase (PylRS), which is used to incorporate various lysine derivatives into proteins. The widely used PylRS from Methanosarcinaceae comprises two distinct domains while the bacterial molecules consist of two separate polypeptides. The recently identified PylRS from Candidatus Methanomethylophilus alvus (CMaPylRS) is a single-domain, one-polypeptide enzyme that belongs to a third category. In the present study, we showed that the PylRS—tRNAPyl pair from C. M. alvus can incorporate lysine derivatives much more efficiently (up to 14-times) than Methanosarcinaceae PylRSs in Escherichia coli cell-based and cell-free systems. Then we investigated the tRNA and amino-acid recognition by CMaPylRS. The cognate tRNAPyl has two structural idiosyncrasies: no connecting nucleotide between the acceptor and D stems and an additional nucleotide in the anticodon stem and it was found that these features are hardly recognized by CMaPylRS. Lastly, the Tyr126Ala and Met129Leu substitutions at the amino-acid binding pocket were shown to allow CMaPylRS to recognize various derivatives of the bulky Nε-benzyloxycarbonyl-l-lysine (ZLys). With the high incorporation efficiency and the amenability to engineering, CMaPylRS would enhance the availability of lysine derivatives in expanded codes.
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17
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Schmitt MA, Biddle W, Fisk JD. Mapping the Plasticity of the Escherichia coli Genetic Code with Orthogonal Pair-Directed Sense Codon Reassignment. Biochemistry 2018; 57:2762-2774. [PMID: 29668270 DOI: 10.1021/acs.biochem.8b00177] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The relative quantitative importance of the factors that determine the fidelity of translation is largely unknown, which makes predicting the extent to which the degeneracy of the genetic code can be broken challenging. Our strategy of using orthogonal tRNA/aminoacyl tRNA synthetase pairs to precisely direct the incorporation of a single amino acid in response to individual sense and nonsense codons provides a suite of related data with which to examine the plasticity of the code. Each directed sense codon reassignment measurement is an in vivo competition experiment between the introduced orthogonal translation machinery and the natural machinery in Escherichia coli. This report discusses 20 new, related genetic codes, in which a targeted E. coli wobble codon is reassigned to tyrosine utilizing the orthogonal tyrosine tRNA/aminoacyl tRNA synthetase pair from Methanocaldococcus jannaschii. One at a time, reassignment of each targeted sense codon to tyrosine is quantified in cells by measuring the fluorescence of GFP variants in which the essential tyrosine residue is encoded by a non-tyrosine codon. Significantly, every wobble codon analyzed may be partially reassigned with efficiencies ranging from 0.8 to 41%. The accumulation of the suite of data enables a qualitative dissection of the relative importance of the factors affecting the fidelity of translation. While some correlation was observed between sense codon reassignment and either competing endogenous tRNA abundance or changes in aminoacylation efficiency of the altered orthogonal system, no single factor appears to predominately drive translational fidelity. Evaluation of relative cellular fitness in each of the 20 quantitatively characterized proteome-wide tyrosine substitution systems suggests that at a systems level, E. coli is robust to missense mutations.
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Affiliation(s)
- Margaret A Schmitt
- Department of Chemical and Biological Engineering , Colorado State University , Fort Collins , Colorado 80523 , United States
| | - Wil Biddle
- Department of Chemistry , Colorado State University , Fort Collins , Colorado 80523 , United States
| | - John D Fisk
- Department of Chemical and Biological Engineering , Colorado State University , Fort Collins , Colorado 80523 , United States.,Department of Chemistry , Colorado State University , Fort Collins , Colorado 80523 , United States.,School of Biomedical Engineering , Colorado State University , Fort Collins , Colorado 80523 , United States
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18
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Abstract
Our understanding of the complex molecular processes of living organisms at the molecular level is growing exponentially. This knowledge, together with a powerful arsenal of tools for manipulating the structures of macromolecules, is allowing chemists to to harness and reprogram the cellular machinery in ways previously unimaged. Here we review one example in which the genetic code itself has been expanded with new building blocks that allow us to probe and manipulate the structures and functions of proteins with unprecedented precision.
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Affiliation(s)
- Douglas D. Young
- Department of Chemistry, College of William & Mary,
P.O. Box 8795, Williamsburg, VA 23187 (USA)
| | - Peter G. Schultz
- Department of Chemistry, The Scripps Research Institute,
La Jolla, CA 92037 (USA),
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19
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Chin JW. Expanding and reprogramming the genetic code. Nature 2017; 550:53-60. [PMID: 28980641 DOI: 10.1038/nature24031] [Citation(s) in RCA: 486] [Impact Index Per Article: 69.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 08/22/2017] [Indexed: 12/13/2022]
Abstract
Nature uses a limited, conservative set of amino acids to synthesize proteins. The ability to genetically encode an expanded set of building blocks with new chemical and physical properties is transforming the study, manipulation and evolution of proteins, and is enabling diverse applications, including approaches to probe, image and control protein function, and to precisely engineer therapeutics. Underpinning this transformation are strategies to engineer and rewire translation. Emerging strategies aim to reprogram the genetic code so that noncanonical biopolymers can be synthesized and evolved, and to test the limits of our ability to engineer the translational machinery and systematically recode genomes.
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Affiliation(s)
- Jason W Chin
- Medical Research Council Laboratory of Molecular Biology, Cambridge CB2 0QH, UK.,Department of Chemistry, Cambridge University, Cambridge CB2 1EW, UK
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20
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Abstract
Pyrrolysine is the 22nd proteinogenic amino acid encoded into proteins in response to amber (TAG) codons in a small number of archaea and bacteria. The incorporation of pyrrolysine is facilitated by a specialized aminoacyl-tRNA synthetase (PylRS) and its cognate tRNA (tRNAPyl). The secondary structure of tRNAPyl contains several unique features not found in canonical tRNAs. Numerous studies have demonstrated that the PylRS/tRNAPyl pair from archaea is orthogonal in E. coli and eukaryotic hosts, which has led to the widespread use of this pair for the genetic incorporation of non-canonical amino acids. In this brief review we examine the work that has been done to elucidate the structure of tRNAPyl, its interaction with PylRS, and survey recent progress on the use of tRNAPyl as a tool for genetic code expansion.
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Affiliation(s)
- Jeffery M Tharp
- a Department of Chemistry , Texas A&M University , College Station , TX , USA
| | - Andreas Ehnbom
- a Department of Chemistry , Texas A&M University , College Station , TX , USA
| | - Wenshe R Liu
- a Department of Chemistry , Texas A&M University , College Station , TX , USA
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21
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Cui Z, Mureev S, Polinkovsky ME, Tnimov Z, Guo Z, Durek T, Jones A, Alexandrov K. Combining Sense and Nonsense Codon Reassignment for Site-Selective Protein Modification with Unnatural Amino Acids. ACS Synth Biol 2017; 6:535-544. [PMID: 27966891 DOI: 10.1021/acssynbio.6b00245] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Incorporation of unnatural amino acids (uAAs) via codon reassignment is a powerful approach for introducing novel chemical and biological properties to synthesized polypeptides. However, the site-selective incorporation of multiple uAAs into polypeptides is hampered by the limited number of reassignable nonsense codons. This challenge is addressed in the current work by developing Escherichia coli in vitro translation system depleted of specific endogenous tRNAs. The translational activity in this system is dependent on the addition of synthetic tRNAs for the chosen sense codon. This allows site-selective uAA incorporation via addition of tRNAs pre- or cotranslationally charged with uAA. We demonstrate the utility of this system by incorporating the BODIPY fluorophore into the unique AGG codon of the calmodulin(CaM) open reading frame using in vitro precharged BODIPY-tRNACysCCU. The deacylated tRNACysCCU is a poor substrate for Cysteinyl-tRNA synthetase, which ensures low background incorporation of Cys into the chosen codon. Simultaneously, p-azidophenylalanine mediated amber-codon suppression and its post-translational conjugation to tetramethylrhodamine dibenzocyclooctyne (TAMRA-DIBO) were performed on the same polypeptide. This simple and robust approach takes advantage of the compatibility of BODIPY fluorophore with the translational machinery and thus requires only one post-translational derivatization step to introduce two fluorescent labels. Using this approach, we obtained CaM nearly homogeneously labeled with two FRET-forming fluorophores. Single molecule FRET analysis revealed dramatic changes in the conformation of the CaM probe upon its exposure to Ca2+ or a chelating agent. The presented approach is applicable to other sense codons and can be directly transferred to eukaryotic cell-free systems.
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Affiliation(s)
- Zhenling Cui
- Institute
for Molecular Bioscience, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Sergey Mureev
- Institute
for Molecular Bioscience, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Mark E. Polinkovsky
- StemProtein, 6350 Nancy
Ridge Drive, San Diego, California 92121, United States
| | - Zakir Tnimov
- Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, United Kingdom
| | - Zhong Guo
- Institute
for Molecular Bioscience, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Thomas Durek
- Institute
for Molecular Bioscience, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Alun Jones
- Institute
for Molecular Bioscience, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Kirill Alexandrov
- Institute
for Molecular Bioscience, The University of Queensland, St Lucia, QLD 4072, Australia
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22
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Lin X, Yu ACS, Chan TF. Efforts and Challenges in Engineering the Genetic Code. Life (Basel) 2017; 7:life7010012. [PMID: 28335420 PMCID: PMC5370412 DOI: 10.3390/life7010012] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Revised: 03/09/2017] [Accepted: 03/10/2017] [Indexed: 12/15/2022] Open
Abstract
This year marks the 48th anniversary of Francis Crick’s seminal work on the origin of the genetic code, in which he first proposed the “frozen accident” hypothesis to describe evolutionary selection against changes to the genetic code that cause devastating global proteome modification. However, numerous efforts have demonstrated the viability of both natural and artificial genetic code variations. Recent advances in genetic engineering allow the creation of synthetic organisms that incorporate noncanonical, or even unnatural, amino acids into the proteome. Currently, successful genetic code engineering is mainly achieved by creating orthogonal aminoacyl-tRNA/synthetase pairs to repurpose stop and rare codons or to induce quadruplet codons. In this review, we summarize the current progress in genetic code engineering and discuss the challenges, current understanding, and future perspectives regarding genetic code modification.
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Affiliation(s)
- Xiao Lin
- School of Life Sciences, The Chinese University of Hong Kong, Sha Tin, NT, Hong Kong, China.
| | - Allen Chi Shing Yu
- School of Life Sciences, The Chinese University of Hong Kong, Sha Tin, NT, Hong Kong, China.
| | - Ting Fung Chan
- School of Life Sciences, The Chinese University of Hong Kong, Sha Tin, NT, Hong Kong, China.
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23
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Future of the Genetic Code. Life (Basel) 2017; 7:life7010010. [PMID: 28264473 PMCID: PMC5370410 DOI: 10.3390/life7010010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Revised: 02/20/2017] [Accepted: 02/23/2017] [Indexed: 11/17/2022] Open
Abstract
The methods for establishing synthetic lifeforms with rewritten genetic codes comprising non-canonical amino acids (NCAA) in addition to canonical amino acids (CAA) include proteome-wide replacement of CAA, insertion through suppression of nonsense codon, and insertion via the pyrrolysine and selenocysteine pathways. Proteome-wide reassignments of nonsense codons and sense codons are also under development. These methods enable the application of NCAAs to enrich both fundamental and applied aspects of protein chemistry and biology. Sense codon reassignment to NCAA could incur problems arising from the usage of anticodons as identity elements on tRNA, and possible misreading of NNY codons by UNN anticodons. Evidence suggests that the problem of anticodons as identity elements can be diminished or resolved through removal from the tRNA of all identity elements besides the anticodon, and the problem of misreading of NNY codons by UNN anticodon can be resolved by the retirement of both the UNN anticodon and its complementary NNA codon from the proteome in the event that a restrictive post-transcriptional modification of the UNN anticodon by host enzymes to prevent the misreading cannot be obtained.
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24
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Biddle W, Schmitt MA, Fisk JD. Modification of orthogonal tRNAs: unexpected consequences for sense codon reassignment. Nucleic Acids Res 2016; 44:10042-10050. [PMID: 27915288 PMCID: PMC5137457 DOI: 10.1093/nar/gkw948] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Revised: 10/05/2016] [Accepted: 10/10/2016] [Indexed: 12/25/2022] Open
Abstract
Breaking the degeneracy of the genetic code via sense codon reassignment has emerged as a way to incorporate multiple copies of multiple non-canonical amino acids into a protein of interest. Here, we report the modification of a normally orthogonal tRNA by a host enzyme and show that this adventitious modification has a direct impact on the activity of the orthogonal tRNA in translation. We observed nearly equal decoding of both histidine codons, CAU and CAC, by an engineered orthogonal M. jannaschii tRNA with an AUG anticodon: tRNAOpt. We suspected a modification of the tRNAOptAUG anticodon was responsible for the anomalous lack of codon discrimination and demonstrate that adenosine 34 of tRNAOptAUG is converted to inosine. We identified tRNAOptAUG anticodon loop variants that increase reassignment of the histidine CAU codon, decrease incorporation in response to the histidine CAC codon, and improve cell health and growth profiles. Recognizing tRNA modification as both a potential pitfall and avenue of directed alteration will be important as the field of genetic code engineering continues to infiltrate the genetic codes of diverse organisms.
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Affiliation(s)
- Wil Biddle
- Department of Chemistry, Colorado State University, Fort Collins, CO 80523, USA
| | - Margaret A Schmitt
- Department of Chemical and Biological Engineering, Colorado State University, Fort Collins, CO 80523, USA
| | - John D Fisk
- Department of Chemistry, Colorado State University, Fort Collins, CO 80523, USA .,Department of Chemical and Biological Engineering, Colorado State University, Fort Collins, CO 80523, USA.,School of Biomedical Engineering, Colorado State University, Fort Collins, CO 80523, USA
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25
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Wang Y, Tsao ML. Reassigning Sense Codon AGA to Encode Noncanonical Amino Acids in Escherichia coli. Chembiochem 2016; 17:2234-2239. [PMID: 27647777 DOI: 10.1002/cbic.201600448] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Indexed: 11/06/2022]
Abstract
A new method has been developed to reassign the rare codon AGA in Escherichia coli by engineering an orthogonal tRNA/aminoacyl-tRNA synthetase pair derived from Methanocaldococcus jannaschii. The tRNA mutant was introduced with a UCU anticodon, and the synthetase was evolved to correctly recognize the modified tRNA anticodon loop and to selectively charge a target noncanonical amino acid (NAA) onto the tRNA. In order to maximize the efficiency of AGA codon reassignment, while avoiding the lethal effects caused by global codon reassignment in cellular proteins, an inducible promoter (araBAD) was utilized to provide temporal controls for overexpression of the aminoacyl-tRNA synthetase and switch on codon reassignment. Using this system, we were able to efficiently incorporate p-acetylphenylalanine, O-methyl-tyrosine, and p-iodophenylalanine into proteins in response to AGA codons. Also, we found that E. coli strain GM10 was optimal in achieving the highest AGA reassignment rates. The successful reassignment of AGA codons reported here provides a new avenue to further expand the genetic code.
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Affiliation(s)
- Yiyan Wang
- School of Natural Sciences, University of California, 5200 North Lake Road, Merced, CA, 95343, USA
| | - Meng-Lin Tsao
- School of Natural Sciences, University of California, 5200 North Lake Road, Merced, CA, 95343, USA
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26
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Emergent rules for codon choice elucidated by editing rare arginine codons in Escherichia coli. Proc Natl Acad Sci U S A 2016; 113:E5588-97. [PMID: 27601680 DOI: 10.1073/pnas.1605856113] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The degeneracy of the genetic code allows nucleic acids to encode amino acid identity as well as noncoding information for gene regulation and genome maintenance. The rare arginine codons AGA and AGG (AGR) present a case study in codon choice, with AGRs encoding important transcriptional and translational properties distinct from the other synonymous alternatives (CGN). We created a strain of Escherichia coli with all 123 instances of AGR codons removed from all essential genes. We readily replaced 110 AGR codons with the synonymous CGU codons, but the remaining 13 "recalcitrant" AGRs required diversification to identify viable alternatives. Successful replacement codons tended to conserve local ribosomal binding site-like motifs and local mRNA secondary structure, sometimes at the expense of amino acid identity. Based on these observations, we empirically defined metrics for a multidimensional "safe replacement zone" (SRZ) within which alternative codons are more likely to be viable. To evaluate synonymous and nonsynonymous alternatives to essential AGRs further, we implemented a CRISPR/Cas9-based method to deplete a diversified population of a wild-type allele, allowing us to evaluate exhaustively the fitness impact of all 64 codon alternatives. Using this method, we confirmed the relevance of the SRZ by tracking codon fitness over time in 14 different genes, finding that codons that fall outside the SRZ are rapidly depleted from a growing population. Our unbiased and systematic strategy for identifying unpredicted design flaws in synthetic genomes and for elucidating rules governing codon choice will be crucial for designing genomes exhibiting radically altered genetic codes.
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27
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Ostrov N, Landon M, Guell M, Kuznetsov G, Teramoto J, Cervantes N, Zhou M, Singh K, Napolitano MG, Moosburner M, Shrock E, Pruitt BW, Conway N, Goodman DB, Gardner CL, Tyree G, Gonzales A, Wanner BL, Norville JE, Lajoie MJ, Church GM. Design, synthesis, and testing toward a 57-codon genome. Science 2016; 353:819-22. [PMID: 27540174 DOI: 10.1126/science.aaf3639] [Citation(s) in RCA: 192] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Accepted: 07/21/2016] [Indexed: 01/07/2023]
Abstract
Recoding--the repurposing of genetic codons--is a powerful strategy for enhancing genomes with functions not commonly found in nature. Here, we report computational design, synthesis, and progress toward assembly of a 3.97-megabase, 57-codon Escherichia coli genome in which all 62,214 instances of seven codons were replaced with synonymous alternatives across all protein-coding genes. We have validated 63% of recoded genes by individually testing 55 segments of 50 kilobases each. We observed that 91% of tested essential genes retained functionality with limited fitness effect. We demonstrate identification and correction of lethal design exceptions, only 13 of which were found in 2229 genes. This work underscores the feasibility of rewriting genomes and establishes a framework for large-scale design, assembly, troubleshooting, and phenotypic analysis of synthetic organisms.
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Affiliation(s)
- Nili Ostrov
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Matthieu Landon
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA. Program in Systems Biology, Harvard University, Cambridge, MA 02138, USA. Ecole des Mines de Paris, Mines Paristech, Paris 75272, France
| | - Marc Guell
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA. Wyss Institute for Biologically Inspired Engineering, Boston, MA 02115, USA
| | - Gleb Kuznetsov
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA. Program in Biophysics, Harvard University, Boston, MA 02115, USA
| | - Jun Teramoto
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA. Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
| | - Natalie Cervantes
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Minerva Zhou
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Kerry Singh
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Michael G Napolitano
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA. Program in Biological and Biomedical Sciences, Harvard University, Cambridge, MA 02138, USA
| | - Mark Moosburner
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Ellen Shrock
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Benjamin W Pruitt
- Wyss Institute for Biologically Inspired Engineering, Boston, MA 02115, USA
| | - Nicholas Conway
- Wyss Institute for Biologically Inspired Engineering, Boston, MA 02115, USA
| | - Daniel B Goodman
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA. Wyss Institute for Biologically Inspired Engineering, Boston, MA 02115, USA
| | - Cameron L Gardner
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Gary Tyree
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | | | - Barry L Wanner
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA. Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Julie E Norville
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Marc J Lajoie
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA.
| | - George M Church
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA. Wyss Institute for Biologically Inspired Engineering, Boston, MA 02115, USA.
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28
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Crnković A, Suzuki T, Söll D, Reynolds NM. Pyrrolysyl-tRNA synthetase, an aminoacyl-tRNA synthetase for genetic code expansion. CROAT CHEM ACTA 2016; 89:163-174. [PMID: 28239189 PMCID: PMC5321558 DOI: 10.5562/cca2825] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Genetic code expansion (GCE) has become a central topic of synthetic biology. GCE relies on engineered aminoacyl-tRNA synthetases (aaRSs) and a cognate tRNA species to allow codon reassignment by co-translational insertion of non-canonical amino acids (ncAAs) into proteins. Introduction of such amino acids increases the chemical diversity of recombinant proteins endowing them with novel properties. Such proteins serve in sophisticated biochemical and biophysical studies both in vitro and in vivo, they may become unique biomaterials or therapeutic agents, and they afford metabolic dependence of genetically modified organisms for biocontainment purposes. In the Methanosarcinaceae the incorporation of the 22nd genetically encoded amino acid, pyrrolysine (Pyl), is facilitated by pyrrolysyl-tRNA synthetase (PylRS) and the cognate UAG-recognizing tRNAPyl. This unique aaRS•tRNA pair functions as an orthogonal translation system (OTS) in most model organisms. The facile directed evolution of the large PylRS active site to accommodate many ncAAs, and the enzyme's anticodon-blind specific recognition of the cognate tRNAPyl make this system highly amenable for GCE purposes. The remarkable polyspecificity of PylRS has been exploited to incorporate >100 different ncAAs into proteins. Here we review the Pyl-OT system and selected GCE applications to examine the properties of an effective OTS.
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Affiliation(s)
- Ana Crnković
- Department of Molecular Biophysics & Biochemistry, Yale University, New Haven, CT 06520-8114, USA
| | - Tateki Suzuki
- Department of Molecular Biophysics & Biochemistry, Yale University, New Haven, CT 06520-8114, USA
| | - Dieter Söll
- Department of Molecular Biophysics & Biochemistry, Yale University, New Haven, CT 06520-8114, USA
- Department of Chemistry, Yale University, New Haven, CT 06520-8114, USA
| | - Noah M. Reynolds
- Department of Molecular Biophysics & Biochemistry, Yale University, New Haven, CT 06520-8114, USA
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29
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McKenney KM, Alfonzo JD. From Prebiotics to Probiotics: The Evolution and Functions of tRNA Modifications. Life (Basel) 2016; 6:E13. [PMID: 26985907 PMCID: PMC4810244 DOI: 10.3390/life6010013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Revised: 02/27/2016] [Accepted: 03/07/2016] [Indexed: 12/13/2022] Open
Abstract
All nucleic acids in cells are subject to post-transcriptional chemical modifications. These are catalyzed by a myriad of enzymes with exquisite specificity and that utilize an often-exotic array of chemical substrates. In no molecule are modifications more prevalent than in transfer RNAs. In the present document, we will attempt to take a chemical rollercoaster ride from prebiotic times to the present, with nucleoside modifications as key players and tRNA as the centerpiece that drove the evolution of biological systems to where we are today. These ideas will be put forth while touching on several examples of tRNA modification enzymes and their modus operandi in cells. In passing, we submit that the choice of tRNA is not a whimsical one but rather highlights its critical function as an essential invention for the evolution of protein enzymes.
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Affiliation(s)
- Katherine M McKenney
- The Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA.
- The Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA.
| | - Juan D Alfonzo
- The Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA.
- The Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA.
- Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA.
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30
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Ho JM, Reynolds NM, Rivera K, Connolly M, Guo LT, Ling J, Pappin DJ, Church GM, Söll D. Efficient Reassignment of a Frequent Serine Codon in Wild-Type Escherichia coli. ACS Synth Biol 2016; 5:163-71. [PMID: 26544153 DOI: 10.1021/acssynbio.5b00197] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Expansion of the genetic code through engineering the translation machinery has greatly increased the chemical repertoire of the proteome. This has been accomplished mainly by read-through of UAG or UGA stop codons by the noncanonical aminoacyl-tRNA of choice. While stop codon read-through involves competition with the translation release factors, sense codon reassignment entails competition with a large pool of endogenous tRNAs. We used an engineered pyrrolysyl-tRNA synthetase to incorporate 3-iodo-l-phenylalanine (3-I-Phe) at a number of different serine and leucine codons in wild-type Escherichia coli. Quantitative LC-MS/MS measurements of amino acid incorporation yields carried out in a selected reaction monitoring experiment revealed that the 3-I-Phe abundance at the Ser208AGU codon in superfolder GFP was 65 ± 17%. This method also allowed quantification of other amino acids (serine, 33 ± 17%; phenylalanine, 1 ± 1%; threonine, 1 ± 1%) that compete with 3-I-Phe at both the aminoacylation and decoding steps of translation for incorporation at the same codon position. Reassignments of different serine (AGU, AGC, UCG) and leucine (CUG) codons with the matching tRNA(Pyl) anticodon variants were met with varying success, and our findings provide a guideline for the choice of sense codons to be reassigned. Our results indicate that the 3-iodo-l-phenylalanyl-tRNA synthetase (IFRS)/tRNA(Pyl) pair can efficiently outcompete the cellular machinery to reassign select sense codons in wild-type E. coli.
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Affiliation(s)
- Joanne M. Ho
- Department
of Genetics, Harvard Medical School, Boston, Massachusetts 02115, United States
| | | | - Keith Rivera
- Cold Spring Harbor Laboratory, Cold
Spring Harbor, New York 11724, United States
| | - Morgan Connolly
- Cold Spring Harbor Laboratory, Cold
Spring Harbor, New York 11724, United States
| | | | | | - Darryl J. Pappin
- Cold Spring Harbor Laboratory, Cold
Spring Harbor, New York 11724, United States
| | - George M. Church
- Department
of Genetics, Harvard Medical School, Boston, Massachusetts 02115, United States
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31
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Bezerra AR, Guimarães AR, Santos MAS. Non-Standard Genetic Codes Define New Concepts for Protein Engineering. Life (Basel) 2015; 5:1610-28. [PMID: 26569314 PMCID: PMC4695839 DOI: 10.3390/life5041610] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Revised: 10/12/2015] [Accepted: 10/21/2015] [Indexed: 11/16/2022] Open
Abstract
The essential feature of the genetic code is the strict one-to-one correspondence between codons and amino acids. The canonical code consists of three stop codons and 61 sense codons that encode 20% of the amino acid repertoire observed in nature. It was originally designated as immutable and universal due to its conservation in most organisms, but sequencing of genes from the human mitochondrial genomes revealed deviations in codon assignments. Since then, alternative codes have been reported in both nuclear and mitochondrial genomes and genetic code engineering has become an important research field. Here, we review the most recent concepts arising from the study of natural non-standard genetic codes with special emphasis on codon re-assignment strategies that are relevant to engineering genetic code in the laboratory. Recent tools for synthetic biology and current attempts to engineer new codes for incorporation of non-standard amino acids are also reviewed in this article.
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Affiliation(s)
- Ana R Bezerra
- Health Sciences Department, Institute for Biomedicine-iBiMED, University of Aveiro, Campus de Santiago, Aveiro 3810-193, Portugal.
| | - Ana R Guimarães
- Health Sciences Department, Institute for Biomedicine-iBiMED, University of Aveiro, Campus de Santiago, Aveiro 3810-193, Portugal.
| | - Manuel A S Santos
- Health Sciences Department, Institute for Biomedicine-iBiMED, University of Aveiro, Campus de Santiago, Aveiro 3810-193, Portugal.
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32
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Fan C, Xiong H, Reynolds NM, Söll D. Rationally evolving tRNAPyl for efficient incorporation of noncanonical amino acids. Nucleic Acids Res 2015; 43:e156. [PMID: 26250114 PMCID: PMC4678846 DOI: 10.1093/nar/gkv800] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Accepted: 07/27/2015] [Indexed: 12/29/2022] Open
Abstract
Genetic encoding of noncanonical amino acids (ncAAs) into proteins is a powerful approach to study protein functions. Pyrrolysyl-tRNA synthetase (PylRS), a polyspecific aminoacyl-tRNA synthetase in wide use, has facilitated incorporation of a large number of different ncAAs into proteins to date. To make this process more efficient, we rationally evolved tRNAPyl to create tRNAPyl-opt with six nucleotide changes. This improved tRNA was tested as substrate for wild-type PylRS as well as three characterized PylRS variants (Nϵ-acetyllysyl-tRNA synthetase [AcKRS], 3-iodo-phenylalanyl-tRNA synthetase [IFRS], a broad specific PylRS variant [PylRS-AA]) to incorporate ncAAs at UAG codons in super-folder green fluorescence protein (sfGFP). tRNAPyl-opt facilitated a 5-fold increase in AcK incorporation into two positions of sfGFP simultaneously. In addition, AcK incorporation into two target proteins (Escherichia coli malate dehydrogenase and human histone H3) caused homogenous acetylation at multiple lysine residues in high yield. Using tRNAPyl-opt with PylRS and various PylRS variants facilitated efficient incorporation of six other ncAAs into sfGFP. Kinetic analyses revealed that the mutations in tRNAPyl-opt had no significant effect on the catalytic efficiency and substrate binding of PylRS enzymes. Thus tRNAPyl-opt should be an excellent replacement of wild-type tRNAPyl for future ncAA incorporation by PylRS enzymes.
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Affiliation(s)
- Chenguang Fan
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520-8144, USA
| | - Hai Xiong
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520-8144, USA
| | - Noah M Reynolds
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520-8144, USA
| | - Dieter Söll
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520-8144, USA Department of Chemistry, Yale University, New Haven, CT 06520-8144, USA
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33
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Mukai T, Yamaguchi A, Ohtake K, Takahashi M, Hayashi A, Iraha F, Kira S, Yanagisawa T, Yokoyama S, Hoshi H, Kobayashi T, Sakamoto K. Reassignment of a rare sense codon to a non-canonical amino acid in Escherichia coli. Nucleic Acids Res 2015; 43:8111-22. [PMID: 26240376 PMCID: PMC4652775 DOI: 10.1093/nar/gkv787] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 07/22/2015] [Indexed: 11/13/2022] Open
Abstract
The immutability of the genetic code has been challenged with the successful reassignment of the UAG stop codon to non-natural amino acids in Escherichia coli. In the present study, we demonstrated the in vivo reassignment of the AGG sense codon from arginine to L-homoarginine. As the first step, we engineered a novel variant of the archaeal pyrrolysyl-tRNA synthetase (PylRS) able to recognize L-homoarginine and L-N(6)-(1-iminoethyl)lysine (L-NIL). When this PylRS variant or HarRS was expressed in E. coli, together with the AGG-reading tRNA(Pyl) CCU molecule, these arginine analogs were efficiently incorporated into proteins in response to AGG. Next, some or all of the AGG codons in the essential genes were eliminated by their synonymous replacements with other arginine codons, whereas the majority of the AGG codons remained in the genome. The bacterial host's ability to translate AGG into arginine was then restricted in a temperature-dependent manner. The temperature sensitivity caused by this restriction was rescued by the translation of AGG to L-homoarginine or L-NIL. The assignment of AGG to L-homoarginine in the cells was confirmed by mass spectrometric analyses. The results showed the feasibility of breaking the degeneracy of sense codons to enhance the amino-acid diversity in the genetic code.
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Affiliation(s)
- Takahito Mukai
- Division of Structural and Synthetic Biology, RIKEN Center for Life Science Technologies, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045, Japan RIKEN Systems and Structural Biology Center, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045, Japan
| | - Atsushi Yamaguchi
- Division of Structural and Synthetic Biology, RIKEN Center for Life Science Technologies, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045, Japan
| | - Kazumasa Ohtake
- Division of Structural and Synthetic Biology, RIKEN Center for Life Science Technologies, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045, Japan
| | - Mihoko Takahashi
- Division of Structural and Synthetic Biology, RIKEN Center for Life Science Technologies, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045, Japan
| | - Akiko Hayashi
- Division of Structural and Synthetic Biology, RIKEN Center for Life Science Technologies, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045, Japan RIKEN Systems and Structural Biology Center, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045, Japan
| | - Fumie Iraha
- Division of Structural and Synthetic Biology, RIKEN Center for Life Science Technologies, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045, Japan
| | - Satoshi Kira
- RIKEN Systems and Structural Biology Center, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045, Japan
| | - Tatsuo Yanagisawa
- RIKEN Systems and Structural Biology Center, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045, Japan RIKEN Structural Biology Laboratory, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045, Japan
| | - Shigeyuki Yokoyama
- RIKEN Systems and Structural Biology Center, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045, Japan RIKEN Structural Biology Laboratory, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045, Japan
| | - Hiroko Hoshi
- RIKEN Systems and Structural Biology Center, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045, Japan
| | - Takatsugu Kobayashi
- RIKEN Systems and Structural Biology Center, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045, Japan
| | - Kensaku Sakamoto
- Division of Structural and Synthetic Biology, RIKEN Center for Life Science Technologies, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045, Japan RIKEN Systems and Structural Biology Center, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045, Japan
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34
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Lee BS, Shin S, Jeon JY, Jang KS, Lee BY, Choi S, Yoo TH. Incorporation of Unnatural Amino Acids in Response to the AGG Codon. ACS Chem Biol 2015; 10:1648-53. [PMID: 25946114 DOI: 10.1021/acschembio.5b00230] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The biological protein synthesis system has been engineered to incorporate unnatural amino acid into proteins, and this has opened up new routes for engineering proteins with novel compositions. While such systems have been successfully applied in research, there remains a need to develop new approaches with respect to the wider application of unnatural amino acids. In this study, we reported a strategy for incorporating unnatural amino acids into proteins by reassigning one of the Arg sense codons, the AGG codon. Using this method, several unnatural amino acids were quantitatively incorporated into the AGG site. Furthermore, we applied the method to multiple AGG sites, and even to tandem AGG sequences. The method developed and described here could be used for engineering proteins with diverse unnatural amino acids, particularly when employed in combination with other methods.
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Affiliation(s)
| | | | | | - Kyoung-Soon Jang
- Division
of Mass Spectrometry Research, Korea Basic Science Institute, 162
Yeongudanji-ro, Ochang-eup, Cheongwon-gu, Cheongju 363-883, Korea
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35
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Lim SI, Kwon I. Bioconjugation of therapeutic proteins and enzymes using the expanded set of genetically encoded amino acids. Crit Rev Biotechnol 2015; 36:803-15. [DOI: 10.3109/07388551.2015.1048504] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Sung In Lim
- Department of Chemical Engineering, University of Virginia, Charlottesville, VA, USA and
| | - Inchan Kwon
- Department of Chemical Engineering, University of Virginia, Charlottesville, VA, USA and
- School of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju, Republic of Korea
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36
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Reducing the genetic code induces massive rearrangement of the proteome. Proc Natl Acad Sci U S A 2014; 111:17206-11. [PMID: 25404328 DOI: 10.1073/pnas.1420193111] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Expanding the genetic code is an important aim of synthetic biology, but some organisms developed naturally expanded genetic codes long ago over the course of evolution. Less than 1% of all sequenced genomes encode an operon that reassigns the stop codon UAG to pyrrolysine (Pyl), a genetic code variant that results from the biosynthesis of Pyl-tRNA(Pyl). To understand the selective advantage of genetically encoding more than 20 amino acids, we constructed a markerless tRNA(Pyl) deletion strain of Methanosarcina acetivorans (ΔpylT) that cannot decode UAG as Pyl or grow on trimethylamine. Phenotypic defects in the ΔpylT strain were evident in minimal medium containing methanol. Proteomic analyses of wild type (WT) M. acetivorans and ΔpylT cells identified 841 proteins from >7,000 significant peptides detected by MS/MS. Protein production from UAG-containing mRNAs was verified for 19 proteins. Translation of UAG codons was verified by MS/MS for eight proteins, including identification of a Pyl residue in PylB, which catalyzes the first step of Pyl biosynthesis. Deletion of tRNA(Pyl) globally altered the proteome, leading to >300 differentially abundant proteins. Reduction of the genetic code from 21 to 20 amino acids led to significant down-regulation in translation initiation factors, amino acid metabolism, and methanogenesis from methanol, which was offset by a compensatory (100-fold) up-regulation in dimethyl sulfide metabolic enzymes. The data show how a natural proteome adapts to genetic code reduction and indicate that the selective value of an expanded genetic code is related to carbon source range and metabolic efficiency.
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37
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Abstract
Pyrrolysyl-tRNA synthetase (PylRS) and its cognate tRNA(Pyl) have emerged as ideal translation components for genetic code innovation. Variants of the enzyme facilitate the incorporation >100 noncanonical amino acids (ncAAs) into proteins. PylRS variants were previously selected to acylate N(ε)-acetyl-Lys (AcK) onto tRNA(Pyl). Here, we examine an N(ε)-acetyl-lysyl-tRNA synthetase (AcKRS), which is polyspecific (i.e., active with a broad range of ncAAs) and 30-fold more efficient with Phe derivatives than it is with AcK. Structural and biochemical data reveal the molecular basis of polyspecificity in AcKRS and in a PylRS variant [iodo-phenylalanyl-tRNA synthetase (IFRS)] that displays both enhanced activity and substrate promiscuity over a chemical library of 313 ncAAs. IFRS, a product of directed evolution, has distinct binding modes for different ncAAs. These data indicate that in vivo selections do not produce optimally specific tRNA synthetases and suggest that translation fidelity will become an increasingly dominant factor in expanding the genetic code far beyond 20 amino acids.
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38
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Abstract
Blowing up: Rapid expansion of the genetic code, beyond what nature initially intended, has given chemical biologists innumerable tools for protein engineering and biological studies. This special issue highlights some of the most recent applications of these techniques in in vivo systems.
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Affiliation(s)
- Edward A Lemke
- European Molecular Biology Laboratory, Structural and Computational Biology Unit, Cell Biology and Biophysics Unit, Meyerhofstrasse 1, 69117 Heidelberg (Germany).
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