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Jiang HK, Tharp JM. Reprogramming Initiator and Nonsense Codons to Simultaneously Install Three Distinct Noncanonical Amino Acids into Proteins in E. coli. Methods Mol Biol 2023; 2676:101-116. [PMID: 37277627 DOI: 10.1007/978-1-0716-3251-2_7] [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] [Indexed: 06/07/2023]
Abstract
Multiple noncanonical amino acids can be installed into proteins in E. coli using mutually orthogonal aminoacyl-tRNA synthetase and tRNA pairs. Here we describe a protocol for simultaneously installing three distinct noncanonical amino acids into proteins for site-specific bioconjugation at three sites. This method relies on an engineered, UAU-suppressing, initiator tRNA, which is aminoacylated with a noncanonical amino acid by Methanocaldococcus jannaschii tyrosyl-tRNA synthetase. Using this initiator tRNA/aminoacyl-tRNA synthetase pair, together with the pyrrolysyl-tRNA synthetase/tRNAPyl pairs from Methanosarcina mazei and Ca. Methanomethylophilus alvus, three noncanonical amino acids can be installed into proteins in response to the UAU, UAG, and UAA codons.
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Affiliation(s)
- Han-Kai Jiang
- Department of Molecular Biophysics & Biochemistry, Yale University, New Haven, CT, USA
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
- Chemical Biology & Molecular Biophysics Program, Taiwan International Graduate Program, Academia Sinica, Taipei, Taiwan
- Department of Chemistry, National Tsing Hua University, Hsinchu, Taiwan
| | - Jeffery M Tharp
- Department of Biochemistry & Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, USA.
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Aarthy M, George A, Ayyadurai N. Beyond protein tagging: Rewiring the genetic code of fluorescent proteins - A review. Int J Biol Macromol 2021; 191:840-851. [PMID: 34560154 DOI: 10.1016/j.ijbiomac.2021.09.108] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 09/17/2021] [Accepted: 09/17/2021] [Indexed: 11/18/2022]
Abstract
Fluorescent proteins (FP) are an integral part of modern biology due to its diverse biochemical and photophysical properties. The boundaries of FP have been extended through conventional mutagenesis and directed evolution approaches. Engineering of FP based on the standard genetic code consisting of 20 amino acids with limited functional groups restrict its diversification. Degeneracy of genetic code has helped in covering this substantial gap through genetic code engineering, wherein introduction of unnatural amino acid (UAA) analogues resulted in a collection of FP with varying properties. This review features the work carried till date in the area of FP incorporated with UAAs and explores strategies employed for incorporation, impact of UAAs in chromophore and surrounding residues and changes in inherent properties of FP. The long-standing association of FP as a tool for high throughput screening of orthogonal aaRS/tRNA pairs used in site specific incorporation of UAAs is expounded. Insertion of UAAs in FP has enabled their use in contemporary fields such as biophotovoltaics, bioremediation, biosensors, biomaterials and imaging of acidic vesicles. Thus, expansion of genetic code of FP is envisaged to rejig the existing spectra of colors and future research initiative in this direction is expected to glow brighter and brighter.
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Affiliation(s)
- Mayilvahanan Aarthy
- Council of Scientific and Industrial Research (CSIR)-Central Leather Research Institute (CLRI), Chennai 600020, India
| | - Augustine George
- Council of Scientific and Industrial Research (CSIR)-Central Leather Research Institute (CLRI), Chennai 600020, India
| | - Niraikulam Ayyadurai
- Council of Scientific and Industrial Research (CSIR)-Central Leather Research Institute (CLRI), Chennai 600020, India.
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3
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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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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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5
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Jin X, Park OJ, Hong SH. Incorporation of non-standard amino acids into proteins: challenges, recent achievements, and emerging applications. Appl Microbiol Biotechnol 2019; 103:2947-2958. [PMID: 30790000 PMCID: PMC6449208 DOI: 10.1007/s00253-019-09690-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2018] [Revised: 02/07/2019] [Accepted: 02/08/2019] [Indexed: 12/19/2022]
Abstract
The natural genetic code only allows for 20 standard amino acids in protein translation, but genetic code reprogramming enables the incorporation of non-standard amino acids (NSAAs). Proteins containing NSAAs provide enhanced or novel properties and open diverse applications. With increased attention to the recent advancements in synthetic biology, various improved and novel methods have been developed to incorporate single and multiple distinct NSAAs into proteins. However, various challenges remain in regard to NSAA incorporation, such as low yield and misincorporation. In this review, we summarize the recent efforts to improve NSAA incorporation by utilizing orthogonal translational system optimization, cell-free protein synthesis, genomically recoded organisms, artificial codon boxes, quadruplet codons, and orthogonal ribosomes, before closing with a discussion of the emerging applications of NSAA incorporation.
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Affiliation(s)
- Xing Jin
- Department of Chemical and Biological Engineering, Illinois Institute of Technology, Chicago, IL, 60616, USA
| | - Oh-Jin Park
- Department of Chemical and Biological Engineering, Illinois Institute of Technology, Chicago, IL, 60616, USA
- Department of Biological and Chemical Engineering, Yanbian University of Science and Technology, Yanji, Jilin, People's Republic of China
| | - Seok Hoon Hong
- Department of Chemical and Biological Engineering, Illinois Institute of Technology, Chicago, IL, 60616, USA.
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Alignment-based and alignment-free methods converge with experimental data on amino acids coded by stop codons at split between nuclear and mitochondrial genetic codes. Biosystems 2018; 167:33-46. [DOI: 10.1016/j.biosystems.2018.03.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 03/18/2018] [Accepted: 03/19/2018] [Indexed: 12/11/2022]
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Abstract
Accurate incorporation of nonstandard amino acids (nsAAs) is central for genetic code expansion to increase the chemical diversity of proteins. However, aminoacyl-tRNA synthetases are polyspecific and facilitate incorporation of multiple nsAAs. We investigated and repurposed a natural protein degradation pathway, the N-end rule pathway, to devise an innovative system for rapid assessment of the accuracy of nsAA incorporation. Using this tool to monitor incorporation of the nsAA biphenylalanine allowed the identification of tyrosyl-tRNA synthetase (TyrRS) variants with improved amino acid specificity. The evolved TyrRS variants enhanced our ability to contain unwanted proliferation of genetically modified organisms. This posttranslational proofreading system will aid the evolution of orthogonal translation systems for specific incorporation of diverse nsAAs. Incorporation of nonstandard amino acids (nsAAs) leads to chemical diversification of proteins, which is an important tool for the investigation and engineering of biological processes. However, the aminoacyl-tRNA synthetases crucial for this process are polyspecific in regard to nsAAs and standard amino acids. Here, we develop a quality control system called “posttranslational proofreading” to more accurately and rapidly evaluate nsAA incorporation. We achieve this proofreading by hijacking a natural pathway of protein degradation known as the N-end rule, which regulates the lifespan of a protein based on its amino-terminal residue. We find that proteins containing certain desired N-terminal nsAAs have much longer half-lives compared with those proteins containing undesired amino acids. We use the posttranslational proofreading system to further evolve a Methanocaldococcus jannaschii tyrosyl-tRNA synthetase (TyrRS) variant and a tRNATyr species for improved specificity of the nsAA biphenylalanine in vitro and in vivo. Our newly evolved biphenylalanine incorporation machinery enhances the biocontainment and growth of genetically engineered Escherichia coli strains that depend on biphenylalanine incorporation. Finally, we show that our posttranslational proofreading system can be designed for incorporation of other nsAAs by rational engineering of the ClpS protein, which mediates the N-end rule. Taken together, our posttranslational proofreading system for in vivo protein sequence verification presents an alternative paradigm for molecular recognition of amino acids and is a major advance in our ability to accurately expand the genetic code.
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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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Lynagh T, Komnatnyy VV, Pless SA. Unique Contributions of an Arginine Side Chain to Ligand Recognition in a Glutamate-gated Chloride Channel. J Biol Chem 2017; 292:3940-3946. [PMID: 28096462 PMCID: PMC5339774 DOI: 10.1074/jbc.m116.772939] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Revised: 01/11/2017] [Indexed: 11/06/2022] Open
Abstract
Glutamate recognition by neurotransmitter receptors often relies on Arg residues in the binding site, leading to the assumption that charge-charge interactions underlie ligand recognition. However, assessing the precise chemical contribution of Arg side chains to protein function and pharmacology has proven to be exceedingly difficult in such large and complex proteins. Using the in vivo nonsense suppression approach, we report the first successful incorporation of the isosteric, titratable Arg analog, canavanine, into a neurotransmitter receptor in a living cell, utilizing a glutamate-gated chloride channel from the nematode Haemonchus contortus Our data unveil a surprisingly small contribution of charge at a conserved arginine side chain previously suggested to form a salt bridge with the ligand, glutamate. Instead, our data show that Arg contributes crucially to ligand sensitivity via a hydrogen bond network, where Arg interacts both with agonist and with a conserved Thr side chain within the receptor. Together, the data provide a new explanation for the reliance of neurotransmitter receptors on Arg side chains and highlight the exceptional capacity of unnatural amino acid incorporation for increasing our understanding of ligand recognition.
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Affiliation(s)
- Timothy Lynagh
- From the Center for Biopharmaceuticals, Department of Drug Design and Pharmacology, University of Copenhagen, 2100 H Copenhagen, Denmark
| | - Vitaly V Komnatnyy
- From the Center for Biopharmaceuticals, Department of Drug Design and Pharmacology, University of Copenhagen, 2100 H Copenhagen, Denmark
| | - Stephan A Pless
- From the Center for Biopharmaceuticals, Department of Drug Design and Pharmacology, University of Copenhagen, 2100 H Copenhagen, Denmark
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10
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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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11
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Gan Q, Fan C. Increasing the fidelity of noncanonical amino acid incorporation in cell-free protein synthesis. Biochim Biophys Acta Gen Subj 2016; 1861:3047-3052. [PMID: 27919800 DOI: 10.1016/j.bbagen.2016.12.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Revised: 11/04/2016] [Accepted: 12/01/2016] [Indexed: 11/17/2022]
Abstract
BACKGROUND Cell-free protein synthesis provides a robust platform for co-translational incorporation of noncanonical amino acid (ncAA) into proteins to facilitate biological studies and biotechnological applications. Recently, eliminating the activity of release factor 1 has been shown to increase ncAA incorporation in response to amber codons. However, this approach could promote mis-incorporation of canonical amino acids by near cognate suppression. METHODS We performed a facile protocol to remove near cognate tRNA isoacceptors of the amber codon from total tRNAs, and used the phosphoserine (Sep) incorporation system as validation. By manipulating codon usage of target genes and tRNA species introduced into the cell-free protein synthesis system, we increased the fidelity of Sep incorporation at a specific position. RESULTS By removing three near cognate tRNA isoacceptors of the amber stop codon [tRNALys, tRNATyr, and tRNAGln(CUG)] from the total tRNA, the near cognate suppression decreased by 5-fold without impairing normal protein synthesis in the cell-free protein synthesis system. Mass spectrometry analyses indicated that the fidelity of ncAA incorporation was improved. CONCLUSIONS Removal of near cognate tRNA isoacceptors of the amber codon could increase ncAA incorporation fidelity towards the amber stop codon in release factor deficiency systems. GENERAL SIGNIFICANCE We provide a general strategy to improve fidelity of ncAA incorporation towards stop, quadruplet and sense codons in cell-free protein synthesis systems. This article is part of a Special Issue entitled "Biochemistry of Synthetic Biology - Recent Developments" Guest Editor: Dr. Ilka Heinemann and Dr. Patrick O'Donoghue.
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Affiliation(s)
- Qinglei Gan
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR 72701, USA
| | - Chenguang Fan
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR 72701, USA.
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12
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Towards Biocontained Cell Factories: An Evolutionarily Adapted Escherichia coli Strain Produces a New-to-nature Bioactive Lantibiotic Containing Thienopyrrole-Alanine. Sci Rep 2016; 6:33447. [PMID: 27634138 PMCID: PMC5025777 DOI: 10.1038/srep33447] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 08/25/2016] [Indexed: 11/08/2022] Open
Abstract
Genetic code engineering that enables reassignment of genetic codons to non-canonical amino acids (ncAAs) is a powerful strategy for enhancing ribosomally synthesized peptides and proteins with functions not commonly found in Nature. Here we report the expression of a ribosomally synthesized and post-translationally modified peptide (RiPP), the 32-mer lantibiotic lichenicidin with a canonical tryptophan (Trp) residue replaced by the ncAA L-β-(thieno[3,2-b]pyrrolyl)alanine ([3,2]Tpa) which does not sustain cell growth in the culture. We have demonstrated that cellular toxicity of [3,2]Tpa for the production of the new-to-nature bioactive congener of lichenicidin in the host Escherichia coli can be alleviated by using an evolutionarily adapted host strain MT21 which not only tolerates [3,2]Tpa but also uses it as a proteome-wide synthetic building block. This work underscores the feasibility of the biocontainment concept and establishes a general framework for design and large scale production of RiPPs with evolutionarily adapted host strains.
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13
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Incorporation of non-canonical amino acids into proteins in yeast. Fungal Genet Biol 2016; 89:137-156. [DOI: 10.1016/j.fgb.2016.02.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Revised: 02/01/2016] [Accepted: 02/03/2016] [Indexed: 12/22/2022]
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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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15
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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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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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Kim H, Siu KH, Raeeszadeh-Sarmazdeh M, Sun Q, Chen Q, Chen W. Bioengineering strategies to generate artificial protein complexes. Biotechnol Bioeng 2015; 112:1495-505. [DOI: 10.1002/bit.25637] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Accepted: 05/01/2015] [Indexed: 01/06/2023]
Affiliation(s)
- Heejae Kim
- Department of Chemical and Biomolecular Engineering; University of Delaware; Newark Delaware 19716
| | - Ka-Hei Siu
- Department of Chemical and Biomolecular Engineering; University of Delaware; Newark Delaware 19716
| | | | - Qing Sun
- Department of Chemical and Biomolecular Engineering; University of Delaware; Newark Delaware 19716
| | - Qi Chen
- Department of Chemical and Biomolecular Engineering; University of Delaware; Newark Delaware 19716
| | - Wilfred Chen
- Department of Chemical and Biomolecular Engineering; University of Delaware; Newark Delaware 19716
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19
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Quast RB, Mrusek D, Hoffmeister C, Sonnabend A, Kubick S. Cotranslational incorporation of non-standard amino acids using cell-free protein synthesis. FEBS Lett 2015; 589:1703-12. [PMID: 25937125 DOI: 10.1016/j.febslet.2015.04.041] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Revised: 04/17/2015] [Accepted: 04/21/2015] [Indexed: 11/30/2022]
Abstract
Over the last years protein engineering using non-standard amino acids has gained increasing attention. As a result, improved methods are now available, enabling the efficient and directed cotranslational incorporation of various non-standard amino acids to equip proteins with desired characteristics. In this context, the utilization of cell-free protein synthesis is particularly useful due to the direct accessibility of the translational machinery and synthesized proteins without having to maintain a vital cellular host. We review prominent methods for the incorporation of non-standard amino acids into proteins using cell-free protein synthesis. Furthermore, a list of non-standard amino acids that have been successfully incorporated into proteins in cell-free systems together with selected applications is provided.
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Affiliation(s)
- Robert B Quast
- Fraunhofer Institute for Cell Therapy and Immunology (IZI), Branch Bioanalytics and Bioprocesses (IZI-BB), Am Mühlenberg 13, 14476 Potsdam, Germany
| | - Devid Mrusek
- Fraunhofer Institute for Cell Therapy and Immunology (IZI), Branch Bioanalytics and Bioprocesses (IZI-BB), Am Mühlenberg 13, 14476 Potsdam, Germany
| | - Christian Hoffmeister
- Fraunhofer Institute for Cell Therapy and Immunology (IZI), Branch Bioanalytics and Bioprocesses (IZI-BB), Am Mühlenberg 13, 14476 Potsdam, Germany
| | - Andrei Sonnabend
- Fraunhofer Institute for Cell Therapy and Immunology (IZI), Branch Bioanalytics and Bioprocesses (IZI-BB), Am Mühlenberg 13, 14476 Potsdam, Germany
| | - Stefan Kubick
- Fraunhofer Institute for Cell Therapy and Immunology (IZI), Branch Bioanalytics and Bioprocesses (IZI-BB), Am Mühlenberg 13, 14476 Potsdam, Germany.
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20
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Dumas A, Lercher L, Spicer CD, Davis BG. Designing logical codon reassignment - Expanding the chemistry in biology. Chem Sci 2015; 6:50-69. [PMID: 28553457 PMCID: PMC5424465 DOI: 10.1039/c4sc01534g] [Citation(s) in RCA: 327] [Impact Index Per Article: 36.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2014] [Accepted: 07/14/2014] [Indexed: 12/18/2022] Open
Abstract
Over the last decade, the ability to genetically encode unnatural amino acids (UAAs) has evolved rapidly. The programmed incorporation of UAAs into recombinant proteins relies on the reassignment or suppression of canonical codons with an amino-acyl tRNA synthetase/tRNA (aaRS/tRNA) pair, selective for the UAA of choice. In order to achieve selective incorporation, the aaRS should be selective for the designed tRNA and UAA over the endogenous amino acids and tRNAs. Enhanced selectivity has been achieved by transferring an aaRS/tRNA pair from another kingdom to the organism of interest, and subsequent aaRS evolution to acquire enhanced selectivity for the desired UAA. Today, over 150 non-canonical amino acids have been incorporated using such methods. This enables the introduction of a large variety of structures into proteins, in organisms ranging from prokaryote, yeast and mammalian cells lines to whole animals, enabling the study of protein function at a level that could not previously be achieved. While most research to date has focused on the suppression of 'non-sense' codons, recent developments are beginning to open up the possibility of quadruplet codon decoding and the more selective reassignment of sense codons, offering a potentially powerful tool for incorporating multiple amino acids. Here, we aim to provide a focused review of methods for UAA incorporation with an emphasis in particular on the different tRNA synthetase/tRNA pairs exploited or developed, focusing upon the different UAA structures that have been incorporated and the logic behind the design and future creation of such systems. Our hope is that this will help rationalize the design of systems for incorporation of unexplored unnatural amino acids, as well as novel applications for those already known.
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Affiliation(s)
- Anaëlle Dumas
- Chemistry Research Laboratory , Department of Chemistry , University of Oxford , Mansfield Road , Oxford , OX1 3TA , UK .
| | - Lukas Lercher
- Chemistry Research Laboratory , Department of Chemistry , University of Oxford , Mansfield Road , Oxford , OX1 3TA , UK .
| | - Christopher D Spicer
- Chemistry Research Laboratory , Department of Chemistry , University of Oxford , Mansfield Road , Oxford , OX1 3TA , UK .
| | - Benjamin G Davis
- Chemistry Research Laboratory , Department of Chemistry , University of Oxford , Mansfield Road , Oxford , OX1 3TA , UK .
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21
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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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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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