1
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Jiang HK, Weng JH, Wang YH, Tsou JC, Chen PJ, Ko ALA, Söll D, Tsai MD, Wang YS. Rational design of the genetic code expansion toolkit for in vivo encoding of D-amino acids. Front Genet 2023; 14:1277489. [PMID: 37904728 PMCID: PMC10613524 DOI: 10.3389/fgene.2023.1277489] [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: 08/14/2023] [Accepted: 09/18/2023] [Indexed: 11/01/2023] Open
Abstract
Once thought to be non-naturally occurring, D-amino acids (DAAs) have in recent years been revealed to play a wide range of physiological roles across the tree of life, including in human systems. Synthetic biologists have since exploited DAAs' unique biophysical properties to generate peptides and proteins with novel or enhanced functions. However, while peptides and small proteins containing DAAs can be efficiently prepared in vitro, producing large-sized heterochiral proteins poses as a major challenge mainly due to absence of pre-existing DAA translational machinery and presence of endogenous chiral discriminators. Based on our previous work demonstrating pyrrolysyl-tRNA synthetase's (PylRS') remarkable substrate polyspecificity, this work attempts to increase PylRS' ability in directly charging tRNAPyl with D-phenylalanine analogs (DFAs). We here report a novel, polyspecific Methanosarcina mazei PylRS mutant, DFRS2, capable of incorporating DFAs into proteins via ribosomal synthesis in vivo. To validate its utility, in vivo translational DAA substitution were performed in superfolder green fluorescent protein and human heavy chain ferritin, successfully altering both proteins' physiochemical properties. Furthermore, aminoacylation kinetic assays further demonstrated aminoacylation of DFAs by DFRS2 in vitro.
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Affiliation(s)
- Han-Kai Jiang
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
- Taiwan International Graduate Program Chemical Biology and Molecular Biophysics, Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
- Department of Chemistry, National Tsing Hua University, Hsinchu, Taiwan
| | - Jui-Hung Weng
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Yi-Hui Wang
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
- Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan
| | - Jo-Chu Tsou
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Pei-Jung Chen
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
- Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan
| | - An-Li Andrea Ko
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Dieter Söll
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, United States
- Department of Chemistry, Yale University, New Haven, CT, United States
| | - Ming-Daw Tsai
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Yane-Shih Wang
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
- Taiwan International Graduate Program Chemical Biology and Molecular Biophysics, Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
- Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan
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2
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Fricke R, Swenson CV, Roe LT, Hamlish NX, Shah B, Zhang Z, Ficaretta E, Ad O, Smaga S, Gee CL, Chatterjee A, Schepartz A. Expanding the substrate scope of pyrrolysyl-transfer RNA synthetase enzymes to include non-α-amino acids in vitro and in vivo. Nat Chem 2023:10.1038/s41557-023-01224-y. [PMID: 37264106 DOI: 10.1038/s41557-023-01224-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 04/28/2023] [Indexed: 06/03/2023]
Abstract
The absence of orthogonal aminoacyl-transfer RNA (tRNA) synthetases that accept non-L-α-amino acids is a primary bottleneck hindering the in vivo translation of sequence-defined hetero-oligomers and biomaterials. Here we report that pyrrolysyl-tRNA synthetase (PylRS) and certain PylRS variants accept α-hydroxy, α-thio and N-formyl-L-α-amino acids, as well as α-carboxy acid monomers that are precursors to polyketide natural products. These monomers are accommodated and accepted by the translation apparatus in vitro; those with reactive nucleophiles are incorporated into proteins in vivo. High-resolution structural analysis of the complex formed between one PylRS enzyme and a m-substituted 2-benzylmalonic acid derivative revealed an active site that discriminates prochiral carboxylates and accommodates the large size and distinct electrostatics of an α-carboxy substituent. This work emphasizes the potential of PylRS-derived enzymes for acylating tRNA with monomers whose α-substituent diverges substantially from the α-amine of proteinogenic amino acids. These enzymes or derivatives thereof could synergize with natural or evolved ribosomes and/or translation factors to generate diverse sequence-defined non-protein heteropolymers.
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Affiliation(s)
- Riley Fricke
- Department of Chemistry, University of California, Berkeley, CA, USA
- Center for Genetically Encoded Materials, University of California, Berkeley, CA, USA
| | - Cameron V Swenson
- Department of Chemistry, University of California, Berkeley, CA, USA
- Center for Genetically Encoded Materials, University of California, Berkeley, CA, USA
| | - Leah Tang Roe
- Department of Chemistry, University of California, Berkeley, CA, USA
- Center for Genetically Encoded Materials, University of California, Berkeley, CA, USA
| | - Noah Xue Hamlish
- Center for Genetically Encoded Materials, University of California, Berkeley, CA, USA
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Bhavana Shah
- Process Development, Amgen, Thousand Oaks, CA, USA
| | | | - Elise Ficaretta
- Center for Genetically Encoded Materials, University of California, Berkeley, CA, USA
- Department of Chemistry, Boston College, Chestnut Hill, MA, USA
| | - Omer Ad
- Department of Chemistry, Yale University, New Haven, CT, USA
| | - Sarah Smaga
- Department of Chemistry, University of California, Berkeley, CA, USA
- Center for Genetically Encoded Materials, University of California, Berkeley, CA, USA
| | - Christine L Gee
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
- Howard Hughes Medical Institute, University of California, Berkeley, CA, USA
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, CA, USA
| | - Abhishek Chatterjee
- Center for Genetically Encoded Materials, University of California, Berkeley, CA, USA
- Department of Chemistry, Boston College, Chestnut Hill, MA, USA
| | - Alanna Schepartz
- Department of Chemistry, University of California, Berkeley, CA, USA.
- Center for Genetically Encoded Materials, University of California, Berkeley, CA, USA.
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA.
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, CA, USA.
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
- Chan Zuckerberg Biohub-San Francisco, San Francisco, CA, USA.
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3
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Yan X, Liu X, Zhao C, Chen GQ. Applications of synthetic biology in medical and pharmaceutical fields. Signal Transduct Target Ther 2023; 8:199. [PMID: 37169742 PMCID: PMC10173249 DOI: 10.1038/s41392-023-01440-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Revised: 03/15/2023] [Accepted: 03/24/2023] [Indexed: 05/13/2023] Open
Abstract
Synthetic biology aims to design or assemble existing bioparts or bio-components for useful bioproperties. During the past decades, progresses have been made to build delicate biocircuits, standardized biological building blocks and to develop various genomic/metabolic engineering tools and approaches. Medical and pharmaceutical demands have also pushed the development of synthetic biology, including integration of heterologous pathways into designer cells to efficiently produce medical agents, enhanced yields of natural products in cell growth media to equal or higher than that of the extracts from plants or fungi, constructions of novel genetic circuits for tumor targeting, controllable releases of therapeutic agents in response to specific biomarkers to fight diseases such as diabetes and cancers. Besides, new strategies are developed to treat complex immune diseases, infectious diseases and metabolic disorders that are hard to cure via traditional approaches. In general, synthetic biology brings new capabilities to medical and pharmaceutical researches. This review summarizes the timeline of synthetic biology developments, the past and present of synthetic biology for microbial productions of pharmaceutics, engineered cells equipped with synthetic DNA circuits for diagnosis and therapies, live and auto-assemblied biomaterials for medical treatments, cell-free synthetic biology in medical and pharmaceutical fields, and DNA engineering approaches with potentials for biomedical applications.
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Affiliation(s)
- Xu Yan
- School of Life Sciences, Tsinghua University, 100084, Beijing, China
| | - Xu Liu
- PhaBuilder Biotech Co. Ltd., Shunyi District, Zhaoquan Ying, 101309, Beijing, China
| | - Cuihuan Zhao
- School of Life Sciences, Tsinghua University, 100084, Beijing, China
| | - Guo-Qiang Chen
- School of Life Sciences, Tsinghua University, 100084, Beijing, China.
- Center for Synthetic and Systems Biology, Tsinghua University, 100084, Beijing, China.
- MOE Key Lab for Industrial Biocatalysis, Dept Chemical Engineering, Tsinghua University, 100084, Beijing, China.
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4
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Moldenhauer M, Tseng HW, Kraskov A, Tavraz NN, Yaroshevich IA, Hildebrandt P, Sluchanko NN, Hochberg GA, Essen LO, Budisa N, Korf L, Maksimov EG, Friedrich T. Parameterization of a single H-bond in Orange Carotenoid Protein by atomic mutation reveals principles of evolutionary design of complex chemical photosystems. Front Mol Biosci 2023; 10:1072606. [PMID: 36776742 PMCID: PMC9909426 DOI: 10.3389/fmolb.2023.1072606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Accepted: 01/17/2023] [Indexed: 01/27/2023] Open
Abstract
Introduction: Dissecting the intricate networks of covalent and non-covalent interactions that stabilize complex protein structures is notoriously difficult and requires subtle atomic-level exchanges to precisely affect local chemical functionality. The function of the Orange Carotenoid Protein (OCP), a light-driven photoswitch involved in cyanobacterial photoprotection, depends strongly on two H-bonds between the 4-ketolated xanthophyll cofactor and two highly conserved residues in the C-terminal domain (Trp288 and Tyr201). Method: By orthogonal translation, we replaced Trp288 in Synechocystis OCP with 3-benzothienyl-L-alanine (BTA), thereby exchanging the imino nitrogen for a sulphur atom. Results: Although the high-resolution (1.8 Å) crystal structure of the fully photoactive OCP-W288_BTA protein showed perfect isomorphism to the native structure, the spectroscopic and kinetic properties changed distinctly. We accurately parameterized the effects of the absence of a single H-bond on the spectroscopic and thermodynamic properties of OCP photoconversion and reveal general principles underlying the design of photoreceptors by natural evolution. Discussion: Such "molecular surgery" is superior over trial-and-error methods in hypothesis-driven research of complex chemical systems.
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Affiliation(s)
- Marcus Moldenhauer
- Department of Bioenergetics, Institute of Chemistry PC 14, Technische Universität Berlin, Berlin, Germany
| | - Hsueh-Wei Tseng
- Department of Biocatalysis, Institute of Chemistry L1, Technische Universität Berlin, Berlin, Germany
| | - Anastasia Kraskov
- Department of Bioenergetics, Institute of Chemistry PC 14, Technische Universität Berlin, Berlin, Germany
| | - Neslihan N. Tavraz
- Department of Bioenergetics, Institute of Chemistry PC 14, Technische Universität Berlin, Berlin, Germany
| | - Igor A. Yaroshevich
- Department of Biophysics, Faculty of Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Peter Hildebrandt
- Department of Bioenergetics, Institute of Chemistry PC 14, Technische Universität Berlin, Berlin, Germany
| | - Nikolai N. Sluchanko
- A.N. Bach Institute of Biochemistry, Federal Research Center Fundamentals of Biotechnology of Russian Academy of Sciences, Moscow, Russia
| | - Georg A. Hochberg
- Max-Planck-Institute of Terrestrial Microbiology, Evolutionary Biochemistry Group, Marburg, Germany
| | - Lars-Oliver Essen
- Department of Chemistry and Unit for Structural Biology, Philipps-Universität Marburg, Marburg, Germany
| | - Nediljko Budisa
- Department of Biocatalysis, Institute of Chemistry L1, Technische Universität Berlin, Berlin, Germany,Department of Chemistry, University of Manitoba, Winnipeg, MB, Canada
| | - Lukas Korf
- Department of Chemistry and Unit for Structural Biology, Philipps-Universität Marburg, Marburg, Germany
| | - Eugene G. Maksimov
- Department of Biophysics, Faculty of Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Thomas Friedrich
- Department of Bioenergetics, Institute of Chemistry PC 14, Technische Universität Berlin, Berlin, Germany,*Correspondence: Thomas Friedrich,
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5
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Guo LT, Amikura K, Jiang HK, Mukai T, Fu X, Wang YS, O'Donoghue P, Söll D, Tharp JM. Ancestral Archaea Expanded the Genetic Code with Pyrrolysine. J Biol Chem 2022; 298:102521. [PMID: 36152750 DOI: 10.1016/j.jbc.2022.102521] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 09/15/2022] [Accepted: 09/16/2022] [Indexed: 10/31/2022] Open
Abstract
The pyrrolysyl-tRNA synthetase (PylRS) facilitates the co-translational installation of the 22nd amino acid pyrrolysine. Owing to its tolerance for diverse amino acid substrates, and its orthogonality in multiple organisms, PylRS has emerged as a major route to install noncanonical amino acids into proteins in living cells. Recently, a novel class of PylRS enzymes was identified in a subset of methanogenic archaea. Enzymes within this class (ΔPylSn) lack the N-terminal tRNA-binding domain that is widely conserved amongst PylRS enzymes, yet remain highly active and orthogonal in bacteria and eukaryotes. In this study, we use biochemical and in vivo UAG-readthrough assays to characterize the aminoacylation efficiency and substrate spectrum of a ΔPylSn class PylRS from the archaeon Ca. Methanomethylophilus alvus. We show that, compared to the full-length enzyme from Methanosarcina mazei, the Ca. M. alvus PylRS displays reduced aminoacylation efficiency, but an expanded amino acid substrate spectrum. To gain insight into the evolution of ΔPylSn enzymes, we performed molecular phylogeny using 156 PylRS and 105 tRNAPyl sequences from diverse anaerobic archaea and bacteria. This analysis suggests that the PylRS•tRNAPyl pair diverged before the evolution of the three domains of life, placing an early limit on the evolution of the Pyl-decoding trait. Furthermore, our results document the co-evolutionary history of PylRS and tRNAPyl and reveal the emergence of tRNAPyl sequences with unique A73 and U73 discriminator bases. The orthogonality of these tRNAPyl species with the more common G73-containing tRNAPyl will enable future efforts to engineer PylRS systems for further genetic code expansion.
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Affiliation(s)
- Li-Tao Guo
- Department of Molecular Biophysics & Biochemistry
| | - Kazuaki Amikura
- Department of Molecular Biophysics & Biochemistry; Department of Interdisciplinary Space Science, Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Kanagawa, Japan
| | - Han-Kai Jiang
- Institute of Biological Chemistry; Chemical Biology and Molecular Biophysics Program, Taiwan International Graduate Program, Academia Sinica, Taipei, Taiwan; Department of Chemistry, National Tsing Hua University, Hsinchu, Taiwan
| | - Takahito Mukai
- Department of Life Science, College of Science, Rikkyo University, Tokyo, Japan
| | - Xian Fu
- BGI-Shenzhen, Shenzhen, China; Guangdong Provincial Key Laboratory of Genome Read and Write, Shenzhen, China
| | - Yane-Shih Wang
- Institute of Biological Chemistry; Chemical Biology and Molecular Biophysics Program, Taiwan International Graduate Program, Academia Sinica, Taipei, Taiwan; Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan
| | - Patrick O'Donoghue
- Department of Biochemistry, The University of Western Ontario, London, Canada; Department of Chemistry, The University of Western Ontario, London, Canada
| | - Dieter Söll
- Department of Molecular Biophysics & Biochemistry; Department of Chemistry, Yale University, New Haven, CT, USA
| | - Jeffery M Tharp
- Department of Molecular Biophysics & Biochemistry; Department of Chemistry, The University of Western Ontario, London, Canada.
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6
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Fischer JT, Söll D, Tharp JM. Directed Evolution of Methanomethylophilus alvus Pyrrolysyl-tRNA Synthetase Generates a Hyperactive and Highly Selective Variant. Front Mol Biosci 2022; 9:850613. [PMID: 35372501 PMCID: PMC8965510 DOI: 10.3389/fmolb.2022.850613] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Accepted: 02/15/2022] [Indexed: 12/12/2022] Open
Abstract
Pyrrolysyl-tRNA synthetase (PylRS) is frequently used for site-specific incorporation of noncanonical amino acids (ncAAs) into proteins. Recently, the active site of Methanomethylophilus alvus PylRS (MaPylRS) has been rationally engineered to expand its substrate compatibility, enabling the incorporation of difficult ncAAs. However, mutations beyond the active site that enhance the enzymatic properties of MaPylRS have not been reported. We utilized phage-assisted non-continuous evolution (PANCE) to evolve MaPylRS to efficiently incorporate Nε-Boc-l-lysine (BocK). Directed evolution yielded several mutations outside of the active site that greatly improve the activity of the enzyme. We combined the most effective mutations to generate a new PylRS variant (PylRSopt) that is highly active and selective towards several lysine and phenylalanine derivatives. The mutations in PylRSopt can be used to enhance previously engineered PylRS constructs such as MaPylRSN166S, and PylRSopt is compatible in applications requiring dual ncAA incorporation and substantially improves the yield of these target proteins.
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Affiliation(s)
- Jonathan T. Fischer
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, United States
- *Correspondence: Jonathan T. Fischer,
| | - Dieter Söll
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, United States
- Department of Chemistry, Yale University, New Haven, CT, United States
| | - Jeffery M. Tharp
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, United States
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7
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Wang YH, Jian ML, Chen PJ, Tsou JC, Truong LP, Wang YS. Ferritin Conjugates With Multiple Clickable Amino Acids Encoded by C-Terminal Engineered Pyrrolysyl-tRNA Synthetase. Front Chem 2021; 9:779976. [PMID: 34900939 PMCID: PMC8655692 DOI: 10.3389/fchem.2021.779976] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 10/20/2021] [Indexed: 11/30/2022] Open
Abstract
This study reports the application of expanding genetic codes in developing protein cage-based delivery systems. The evolved Methanosarcina mazei pyrrolysyl-tRNA synthetase (PylRS)•tRNAPyl pairs derived from directed evolution are examined to probe their recognition for para-substituted phenylalanine analogs. The evolved MmPylRS, AzFRS, harboring a wide range of substrates, is further engineered at the C-terminal region into another variant, AzFRS-MS. AzFRS-MS shows suppression of the elevated sfGFP protein amount up to 10 TAG stop codons when charging p-azido-l-phenylalanine (AzF, 4), which allows the occurrence of click chemistry. Since protein nanocages used as drug delivery systems that encompass multiple drugs through a site-specific loading approach remain largely unexplored, as a proof of concept, the application of AzFRS-MS for the site-specific incorporation of AzF on human heavy chain ferritin (Ftn) is developed. The Ftn-4 conjugate is shown to be able to load multiple fluorescence dyes or a therapeutic agent, doxorubicin (Dox), through the strain-promoted azide-alkyne cycloaddition (SPAAC) click reaction. Aiming to selectively target Her2+ breast cancer cells, Ftn-4-DOX conjugates fused with a HER2 receptor recognition peptide, anti-Her2/neu peptide (AHNP), is developed and demonstrated to be able to deliver Dox into the cell and to prolong the drug release. This work presents another application of evolved MmPylRS systems, whose potential in developing a variety of protein conjugates is noteworthy.
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Affiliation(s)
- Yi-Hui Wang
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Mu-Lung Jian
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan.,Institute of Biochemical Sciences, College of Life Science, National Taiwan University, Taipei, Taiwan
| | - Pei-Jung Chen
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan.,Institute of Biochemical Sciences, College of Life Science, National Taiwan University, Taipei, Taiwan
| | - Jo-Chu Tsou
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan.,Institute of Biochemical Sciences, College of Life Science, National Taiwan University, Taipei, Taiwan
| | - Le P Truong
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Yane-Shih Wang
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan.,Institute of Biochemical Sciences, College of Life Science, National Taiwan University, Taipei, Taiwan
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8
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Koch NG, Goettig P, Rappsilber J, Budisa N. Engineering Pyrrolysyl-tRNA Synthetase for the Incorporation of Non-Canonical Amino Acids with Smaller Side Chains. Int J Mol Sci 2021; 22:11194. [PMID: 34681855 PMCID: PMC8538471 DOI: 10.3390/ijms222011194] [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: 09/19/2021] [Revised: 10/13/2021] [Accepted: 10/14/2021] [Indexed: 01/11/2023] Open
Abstract
Site-specific incorporation of non-canonical amino acids (ncAAs) into proteins has emerged as a universal tool for systems bioengineering at the interface of chemistry, biology, and technology. The diversification of the repertoire of the genetic code has been achieved for amino acids with long and/or bulky side chains equipped with various bioorthogonal tags and useful spectral probes. Although ncAAs with relatively small side chains and similar properties are of great interest to biophysics, cell biology, and biomaterial science, they can rarely be incorporated into proteins. To address this gap, we report the engineering of PylRS variants capable of incorporating an entire library of aliphatic "small-tag" ncAAs. In particular, we performed mutational studies of a specific PylRS, designed to incorporate the shortest non-bulky ncAA (S-allyl-l-cysteine) possible to date and based on this knowledge incorporated aliphatic ncAA derivatives. In this way, we have not only increased the number of translationally active "small-tag" ncAAs, but also determined key residues responsible for maintaining orthogonality, while engineering the PylRS for these interesting substrates. Based on the known plasticity of PylRS toward different substrates, our approach further expands the reassignment capacities of this enzyme toward aliphatic amino acids with smaller side chains endowed with valuable functionalities.
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Affiliation(s)
- Nikolaj G. Koch
- Institut für Chemie, Technische Universität Berlin, 10623 Berlin, Germany;
- Institut für Biotechnologie-Bioanalytik, Technische Universität Berlin, 10623 Berlin, Germany;
| | - Peter Goettig
- Structural Biology Group, Department of Biosciences, University of Salzburg, 5020 Salzburg, Austria;
| | - Juri Rappsilber
- Institut für Biotechnologie-Bioanalytik, Technische Universität Berlin, 10623 Berlin, Germany;
- Wellcome Centre for Cell Biology, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Nediljko Budisa
- Institut für Chemie, Technische Universität Berlin, 10623 Berlin, Germany;
- Department of Chemistry, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
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9
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Bacterial translation machinery for deliberate mistranslation of the genetic code. Proc Natl Acad Sci U S A 2021; 118:2110797118. [PMID: 34413202 DOI: 10.1073/pnas.2110797118] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Inaccurate expression of the genetic code, also known as mistranslation, is an emerging paradigm in microbial studies. Growing evidence suggests that many microbial pathogens can deliberately mistranslate their genetic code to help invade a host or evade host immune responses. However, discovering different capacities for deliberate mistranslation remains a challenge because each group of pathogens typically employs a unique mistranslation mechanism. In this study, we address this problem by studying duplicated genes of aminoacyl-transfer RNA (tRNA) synthetases. Using bacterial prolyl-tRNA synthetase (ProRS) genes as an example, we identify an anomalous ProRS isoform, ProRSx, and a corresponding tRNA, tRNAProA, that are predominately found in plant pathogens from Streptomyces species. We then show that tRNAProA has an unusual hybrid structure that allows this tRNA to mistranslate alanine codons as proline. Finally, we provide biochemical, genetic, and mass spectrometric evidence that cells which express ProRSx and tRNAProA can translate GCU alanine codons as both alanine and proline. This dual use of alanine codons creates a hidden proteome diversity due to stochastic Ala→Pro mutations in protein sequences. Thus, we show that important plant pathogens are equipped with a tool to alter the identity of their sense codons. This finding reveals the initial example of a natural tRNA synthetase/tRNA pair for dedicated mistranslation of sense codons.
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10
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Hao R, Ma K, Ru Y, Li D, Song G, Lu B, Liu H, Li Y, Zhang J, Wu C, Zhang G, Hu H, Luo J, Zheng H. Amber codon is genetically unstable in generation of premature termination codon (PTC)-harbouring Foot-and-mouth disease virus (FMDV) via genetic code expansion. RNA Biol 2021; 18:2330-2341. [PMID: 33849391 DOI: 10.1080/15476286.2021.1907055] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The foot-and-mouth disease virus (FMDV) is the causative agent of FMD, a highly infectious and devastating viral disease of domestic and wild cloven-hoofed animals. FMD affects livestock and animal products' national and international trade, causing severe economic losses and social consequences. Currently, inactivated vaccines play a vital role in FMD control, but they have several limitations. The genetic code expansion technology provides powerful strategies for generating premature termination codon (PTC)-harbouring virus as a live but replication-incompetent viral vaccine. However, this technology has not been explored for the design and development of new FMD vaccines. In this study, we first expanded the genetic code of the FMDV genome via a transgenic cell line containing an orthogonal translation machinery. We demonstrated that the transgenic cells stably integrated the orthogonal pyltRNA/pylRS pair into the genome and enabled efficient, homogeneous incorporation of unnatural amino acids into target proteins in mammalian cells. Next, we constructed 129 single-PTC FMDV mutants and four dual-PTC FMDV mutants after considering the tolerance, location, and potential functions of those mutated sites. Amber stop codons individually substituted the selected amino acid codons in four viral proteins (3D, L, VP1, and VP4) of FMDV. We successfully rescued PTC-FMDV mutants, but the amber codon unexpectedly showed a highly degree of mutation rate during PTC-FMDV packaging and replication. Our findings highlight that the genetic code expansion technology for the generation of PTC-FMD vaccines needs to be further improved and that the genetic stability of amber codons during the packaging and replication of FMDV is a concern.
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Affiliation(s)
- Rongzeng Hao
- State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, OIE/National Foot and Mouth Diseases Reference Laboratory, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Kun Ma
- State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, OIE/National Foot and Mouth Diseases Reference Laboratory, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Yi Ru
- State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, OIE/National Foot and Mouth Diseases Reference Laboratory, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Dan Li
- State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, OIE/National Foot and Mouth Diseases Reference Laboratory, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Gaoyuan Song
- State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, OIE/National Foot and Mouth Diseases Reference Laboratory, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Bingzhou Lu
- State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, OIE/National Foot and Mouth Diseases Reference Laboratory, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Huanan Liu
- State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, OIE/National Foot and Mouth Diseases Reference Laboratory, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Yajun Li
- State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, OIE/National Foot and Mouth Diseases Reference Laboratory, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Jiaoyan Zhang
- State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, OIE/National Foot and Mouth Diseases Reference Laboratory, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Chunping Wu
- State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, OIE/National Foot and Mouth Diseases Reference Laboratory, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Guicai Zhang
- State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, OIE/National Foot and Mouth Diseases Reference Laboratory, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Haitao Hu
- Department of Microbiology and Immunology, Sealy Center for Vaccine Development and Institute for Human Infections and Immunity, University of Texas Medical Branch (UTMB), Galveston, TX, USA
| | - Jianxun Luo
- State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, OIE/National Foot and Mouth Diseases Reference Laboratory, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Haixue Zheng
- State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, OIE/National Foot and Mouth Diseases Reference Laboratory, Chinese Academy of Agricultural Sciences, Lanzhou, China
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11
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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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12
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Tseng HW, Baumann T, Sun H, Wang YS, Ignatova Z, Budisa N. Expanding the Scope of Orthogonal Translation with Pyrrolysyl-tRNA Synthetases Dedicated to Aromatic Amino Acids. Molecules 2020; 25:E4418. [PMID: 32992991 PMCID: PMC7582959 DOI: 10.3390/molecules25194418] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 09/18/2020] [Accepted: 09/22/2020] [Indexed: 11/16/2022] Open
Abstract
In protein engineering and synthetic biology, Methanosarcina mazei pyrrolysyl-tRNA synthetase (MmPylRS), with its cognate tRNAPyl, is one of the most popular tools for site-specific incorporation of non-canonical amino acids (ncAAs). Numerous orthogonal pairs based on engineered MmPylRS variants have been developed during the last decade, enabling a substantial genetic code expansion, mainly with aliphatic pyrrolysine analogs. However, comparatively less progress has been made to expand the substrate range of MmPylRS towards aromatic amino acid residues. Therefore, we set to further expand the substrate scope of orthogonal translation by a semi-rational approach; redesigning the MmPylRS efficiency. Based on the randomization of residues from the binding pocket and tRNA binding domain, we identify three positions (V401, W417 and S193) crucial for ncAA specificity and enzyme activity. Their systematic mutagenesis enabled us to generate MmPylRS variants dedicated to tryptophan (such as β-(1-Azulenyl)-l-alanine or 1-methyl-l-tryptophan) and tyrosine (mainly halogenated) analogs. Moreover, our strategy also significantly improves the orthogonal translation efficiency with the previously activated analog 3-benzothienyl-l-alanine. Our study revealed the engineering of both first shell and distant residues to modify substrate specificity as an important strategy to further expand our ability to discover and recruit new ncAAs for orthogonal translation.
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Affiliation(s)
- Hsueh-Wei Tseng
- Institut für Chemie, Technische Universität Berlin, Müller-Breslau-Straße 10, 10623 Berlin, Germany; (H.-W.T.); (T.B.); (H.S.)
| | - Tobias Baumann
- Institut für Chemie, Technische Universität Berlin, Müller-Breslau-Straße 10, 10623 Berlin, Germany; (H.-W.T.); (T.B.); (H.S.)
| | - Huan Sun
- Institut für Chemie, Technische Universität Berlin, Müller-Breslau-Straße 10, 10623 Berlin, Germany; (H.-W.T.); (T.B.); (H.S.)
| | - Yane-Shih Wang
- Institute of Biological Chemistry, Academia Sinica, Taipei 116, Taiwan;
- Institute of Biochemical Sciences, National Taiwan University, Taipei 116, Taiwan
| | - Zoya Ignatova
- Institute of Biochemistry and Molecular Biology, University of Hamburg, 20146 Hamburg, Germany;
| | - Nediljko Budisa
- Institut für Chemie, Technische Universität Berlin, Müller-Breslau-Straße 10, 10623 Berlin, Germany; (H.-W.T.); (T.B.); (H.S.)
- Department of Chemistry, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
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13
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Crnković A, Vargas-Rodriguez O, Söll D. Plasticity and Constraints of tRNA Aminoacylation Define Directed Evolution of Aminoacyl-tRNA Synthetases. Int J Mol Sci 2019; 20:ijms20092294. [PMID: 31075874 PMCID: PMC6540133 DOI: 10.3390/ijms20092294] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 04/29/2019] [Accepted: 05/07/2019] [Indexed: 02/07/2023] Open
Abstract
Genetic incorporation of noncanonical amino acids (ncAAs) has become a powerful tool to enhance existing functions or introduce new ones into proteins through expanded chemistry. This technology relies on the process of nonsense suppression, which is made possible by directing aminoacyl-tRNA synthetases (aaRSs) to attach an ncAA onto a cognate suppressor tRNA. However, different mechanisms govern aaRS specificity toward its natural amino acid (AA) substrate and hinder the engineering of aaRSs for applications beyond the incorporation of a single l-α-AA. Directed evolution of aaRSs therefore faces two interlinked challenges: the removal of the affinity for cognate AA and improvement of ncAA acylation. Here we review aspects of AA recognition that directly influence the feasibility and success of aaRS engineering toward d- and β-AAs incorporation into proteins in vivo. Emerging directed evolution methods are described and evaluated on the basis of aaRS active site plasticity and its inherent constraints.
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Affiliation(s)
- Ana Crnković
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA.
| | - Oscar Vargas-Rodriguez
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA.
| | - Dieter Söll
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA.
- Department of Chemistry, Yale University, New Haven, CT 06520, USA.
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14
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Vargas-Rodriguez O, Sevostyanova A, Söll D, Crnković A. Upgrading aminoacyl-tRNA synthetases for genetic code expansion. Curr Opin Chem Biol 2018; 46:115-122. [PMID: 30059834 PMCID: PMC6214156 DOI: 10.1016/j.cbpa.2018.07.014] [Citation(s) in RCA: 78] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 05/04/2018] [Accepted: 07/13/2018] [Indexed: 01/06/2023]
Abstract
Synthesis of proteins with non-canonical amino acids via genetic code expansion is at the forefront of synthetic biology. Progress in this field has enabled site-specific incorporation of over 200 chemically and structurally diverse amino acids into proteins in an increasing number of organisms. This has been facilitated by our ability to repurpose aminoacyl-tRNA synthetases to attach non-canonical amino acids to engineered tRNAs. Current efforts in the field focus on overcoming existing limitations to the simultaneous incorporation of multiple non-canonical amino acids or amino acids that differ from the l-α-amino acid structure (e.g. d-amino acid or β-amino acid). Here, we summarize the progress and challenges in developing more selective and efficient aminoacyl-tRNA synthetases for genetic code expansion.
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Affiliation(s)
- Oscar Vargas-Rodriguez
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA.
| | - Anastasia Sevostyanova
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
| | - Dieter Söll
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA; Department of Chemistry, Yale University, New Haven, CT 06520, USA
| | - Ana Crnković
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA.
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15
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de Farias ST, Antonino D, Rêgo TG, José MV. Structural evolution of Glycyl-tRNA synthetases alpha subunit and its implication in the initial organization of the decoding system. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2018; 142:43-50. [PMID: 30142371 DOI: 10.1016/j.pbiomolbio.2018.08.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 07/13/2018] [Accepted: 08/14/2018] [Indexed: 11/27/2022]
Abstract
The origin and evolution of the genetic code is a fundamental challenge in modern biology. At the center of this problem is the correct interaction between amino acids and tRNAs. Aminoacyl-tRNA synthetase is the enzyme responsible for the correct binding between amino acids and tRNAs. Among the 20 canonical amino acid, glycine was the most abundant in prebiotic condition and it must have been one of the first to be incorporated into the genetic code. In this work, we derive the ancestral sequence of Glycyl-tRNA synthetase (GlyRS) and predict its 3D-structure. We show, via molecular docking experiments, the capacity of ancestral GlyRS to bind the tRNA anticodon stem loop, cofactors and substrates. These bindings exhibit high affinity and specificity. We propose that the primordial function of these interactions was to stabilize both compounds to make possible the catalysis. In this context, the anticodon stem loop did contribute to the encoding system and just with the emergence of the mRNA it was co-opted for codification. Thus, we present a model for the origin of the genetic code in which the operational and the anticodon codes did not evolve independently.
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Affiliation(s)
- Savio Torres de Farias
- Laboratório de Genética Evolutiva Paulo Leminsk, Departamento de Biologia Molecular, Universidade Federal da Paraíba, João Pessoa, Brazil.
| | - Daniel Antonino
- Laboratório de Genética Evolutiva Paulo Leminsk, Departamento de Biologia Molecular, Universidade Federal da Paraíba, João Pessoa, Brazil
| | - Thais Gaudêncio Rêgo
- Departamento de Informática, Universidade Federal da Paraíba, João Pessoa, Brazil
| | - Marco V José
- Theoretical Biology Group, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad de México CDMX, C.P. 04510, Mexico.
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16
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Fladischer P, Weingartner A, Blamauer J, Darnhofer B, Birner-Gruenberger R, Kardashliev T, Ruff AJ, Schwaneberg U, Wiltschi B. A Semi-Rationally Engineered Bacterial Pyrrolysyl-tRNA Synthetase Genetically Encodes Phenyl Azide Chemistry. Biotechnol J 2018; 14:e1800125. [DOI: 10.1002/biot.201800125] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 05/25/2018] [Indexed: 11/10/2022]
Affiliation(s)
- Patrik Fladischer
- Acib − Austrian Centre of Industrial Biotechnology; Petersgasse 14 A-8010 Graz Austria
- Institute of Molecular Biotechnology; Graz University of Technology; Graz Austria
| | - Alexandra Weingartner
- Acib − Austrian Centre of Industrial Biotechnology; Petersgasse 14 A-8010 Graz Austria
- Institute of Molecular Biotechnology; Graz University of Technology; Graz Austria
| | - Johannes Blamauer
- Acib − Austrian Centre of Industrial Biotechnology; Petersgasse 14 A-8010 Graz Austria
- Institute of Molecular Biotechnology; Graz University of Technology; Graz Austria
| | - Barbara Darnhofer
- Acib − Austrian Centre of Industrial Biotechnology; Petersgasse 14 A-8010 Graz Austria
- Research Unit Functional Proteomics and Metabolomic Pathways; Institute of Pathology; Medical University of Graz; Graz Austria
- Omics Center Graz; BioTechMed-Graz; Graz Austria
| | - Ruth Birner-Gruenberger
- Research Unit Functional Proteomics and Metabolomic Pathways; Institute of Pathology; Medical University of Graz; Graz Austria
- Omics Center Graz; BioTechMed-Graz; Graz Austria
| | | | - Anna Joelle Ruff
- Lehrstuhl für Biotechnologie; RWTH Aachen University; Aachen Germany
| | | | - Birgit Wiltschi
- Acib − Austrian Centre of Industrial Biotechnology; Petersgasse 14 A-8010 Graz Austria
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17
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Crnković A, Vargas-Rodriguez O, Merkuryev A, Söll D. Effects of Heterologous tRNA Modifications on the Production of Proteins Containing Noncanonical Amino Acids. Bioengineering (Basel) 2018; 5:bioengineering5010011. [PMID: 29393901 PMCID: PMC5874877 DOI: 10.3390/bioengineering5010011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 01/31/2018] [Accepted: 01/31/2018] [Indexed: 12/21/2022] Open
Abstract
Synthesis of proteins with noncanonical amino acids (ncAAs) enables the creation of protein-based biomaterials with diverse new chemical properties that may be attractive for material science. Current methods for large-scale production of ncAA-containing proteins, frequently carried out in Escherichia coli, involve the use of orthogonal aminoacyl-tRNA synthetases (o-aaRSs) and tRNAs (o-tRNAs). Although o-tRNAs are designed to be orthogonal to endogenous aaRSs, their orthogonality to the components of the E. coli metabolism remains largely unexplored. We systematically investigated how the E. coli tRNA modification machinery affects the efficiency and orthogonality of o-tRNASep used for production of proteins with the ncAA O-phosphoserine (Sep). The incorporation of Sep into a green fluorescent protein (GFP) in 42 E. coli strains carrying deletions of single tRNA modification genes identified several genes that affect the o-tRNA activity. Deletion of cysteine desulfurase (iscS) increased the yield of Sep-containing GFP more than eightfold, while overexpression of dimethylallyltransferase MiaA and pseudouridine synthase TruB improved the specificity of Sep incorporation. These results highlight the importance of tRNA modifications for the biosynthesis of proteins containing ncAAs, and provide a novel framework for optimization of o-tRNAs.
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Affiliation(s)
- Ana Crnković
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA.
| | - Oscar Vargas-Rodriguez
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA.
| | - Anna Merkuryev
- Department of Chemistry, Yale University, New Haven, CT 06520, USA.
| | - Dieter Söll
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA.
- Department of Chemistry, Yale University, New Haven, CT 06520, USA.
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18
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Xuan W, Schultz PG. A Strategy for Creating Organisms Dependent on Noncanonical Amino Acids. Angew Chem Int Ed Engl 2017; 56:9170-9173. [PMID: 28593724 PMCID: PMC5580492 DOI: 10.1002/anie.201703553] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Indexed: 11/11/2022]
Abstract
The use of noncanonical amino acids (ncAAs) to control the viability of an organism provides a strategy for the development of conditional "kill switches" for live vaccines or engineered human cells. We report an approach inspired by the posttranslational acetylation/deacetylation of lysine residues, in which a protein encoded by a gene with an in-frame nonsense codon at an essential lysine can be expressed in its native state only upon genetic incorporation of N-ϵ-acetyl-l-Lys (AcK), and subsequent enzymatic deacetylation in the host cell. We applied this strategy to two essential E. coli enzymes: the branched-chain aminotransferase BCAT and the DNA replication initiator protein DnaA. We also devised a barnase-based conditional suicide switch to further lower the escape frequency of the host cells. This strategy offers a number of attractive features for controlling host viability, including a single small-molecule-based kill switch, low escape frequency, and unaffected protein function.
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Affiliation(s)
- Weimin Xuan
- Department of Chemistry, the Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA, 92037, USA
| | - Peter G Schultz
- Department of Chemistry, the Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA, 92037, USA
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19
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Xuan W, Schultz PG. A Strategy for Creating Organisms Dependent on Noncanonical Amino Acids. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201703553] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Weimin Xuan
- Department of Chemistry; the Scripps Research Institute; 10550 N. Torrey Pines Road La Jolla CA 92037 USA
| | - Peter G. Schultz
- Department of Chemistry; the Scripps Research Institute; 10550 N. Torrey Pines Road La Jolla CA 92037 USA
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20
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Englert M, Vargas-Rodriguez O, Reynolds NM, Wang YS, Söll D, Umehara T. A genomically modified Escherichia coli strain carrying an orthogonal E. coli histidyl-tRNA synthetase•tRNA His pair. Biochim Biophys Acta Gen Subj 2017; 1861:3009-3015. [PMID: 28288813 DOI: 10.1016/j.bbagen.2017.03.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Accepted: 03/01/2017] [Indexed: 01/23/2023]
Abstract
BACKGROUND Development of new aminoacyl-tRNA synthetase (aaRS)•tRNA pairs is central for incorporation of novel non-canonical amino acids (ncAAs) into proteins via genetic code expansion (GCE). The Escherichia coli and Caulobacter crescentus histidyl-tRNA synthetases (HisRS) evolved divergent mechanisms of tRNAHis recognition that prevent their cross-reactivity. Although the E. coli HisRS•tRNAHis pair is a good candidate for GCE, its use in C. crescentus is limited by the lack of established genetic selection methods and by the low transformation efficiency of C. crescentus. METHODS E. coli was genetically engineered to use a C. crescentus HisRS•tRNAHis pair. Super-folder green fluorescent protein (sfGFP) and chloramphenicol acetyltransferase (CAT) were used as reporters for read-through assays. A library of 313 ncAAs coupled with the sfGFP reporter system was employed to investigate the specificity of E. coli HisRS in vivo. RESULTS A genomically modified E. coli strain (named MEOV1) was created. MEVO1 requires an active C. crescentus HisRS•tRNAHis pair for growth, and displays a similar doubling time as the parental E. coli strain. sfGFP- and CAT-based assays showed that the E. coli HisRS•tRNAHis pair is orthogonal in MEOV1 cells. A mutation in the anticodon loop of E. coli tRNAHisCUA elevated its suppression efficiency by 2-fold. CONCLUSIONS The C. crescentus HisRS•tRNAHis pair functionally complements an E. coli ΔhisS strain. The E. coli HisRS•tRNAHis is orthogonal in MEOV1 cells. E. coli tRNAHisCUA is an efficient amber suppressor in MEOV1. GENERAL SIGNIFICANCE We developed a platform that allows protein engineering of E. coli HisRS that should facilitate GCE in E. coli. 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)
- Markus Englert
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
| | - Oscar Vargas-Rodriguez
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
| | - Noah M Reynolds
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
| | - Yane-Shih Wang
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
| | - Dieter Söll
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA; Department of Chemistry, Yale University, New Haven, CT 06520, USA.
| | - Takuya Umehara
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA; Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan.
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21
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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: 24] [Impact Index Per Article: 3.0] [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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22
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Melo Czekster C, Robertson WE, Walker AS, Söll D, Schepartz A. In Vivo Biosynthesis of a β-Amino Acid-Containing Protein. J Am Chem Soc 2016; 138:5194-7. [PMID: 27086674 DOI: 10.1021/jacs.6b01023] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
It has recently been reported that ribosomes from erythromycin-resistant Escherichia coli strains, when isolated in S30 extracts and incubated with chemically mis-acylated tRNA, can incorporate certain β-amino acids into full length DHFR in vitro. Here we report that wild-type E. coli EF-Tu and phenylalanyl-tRNA synthetase collaborate with these mutant ribosomes and others to incorporate β(3)-Phe analogs into full length DHFR in vivo. E. coli harboring the most active mutant ribosomes are robust, with a doubling time only 14% longer than wild-type. These results reveal the unexpected tolerance of E. coli and its translation machinery to the β(3)-amino acid backbone and should embolden in vivo selections for orthogonal translational machinery components that incorporate diverse β-amino acids into proteins and peptides. E. coli harboring mutant ribosomes may possess the capacity to incorporate many non-natural, non-α-amino acids into proteins and other sequence-programmed polymeric materials.
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Affiliation(s)
- Clarissa Melo Czekster
- Department of Chemistry, ‡Department of Molecular, Cellular, and Developmental Biology, and §Department of Molecular Biophysics and Biochemistry, Yale University , New Haven, Connecticut 06520-8107, United States
| | - Wesley E Robertson
- Department of Chemistry, ‡Department of Molecular, Cellular, and Developmental Biology, and §Department of Molecular Biophysics and Biochemistry, Yale University , New Haven, Connecticut 06520-8107, United States
| | - Allison S Walker
- Department of Chemistry, ‡Department of Molecular, Cellular, and Developmental Biology, and §Department of Molecular Biophysics and Biochemistry, Yale University , New Haven, Connecticut 06520-8107, United States
| | - Dieter Söll
- Department of Chemistry, ‡Department of Molecular, Cellular, and Developmental Biology, and §Department of Molecular Biophysics and Biochemistry, Yale University , New Haven, Connecticut 06520-8107, United States
| | - Alanna Schepartz
- Department of Chemistry, ‡Department of Molecular, Cellular, and Developmental Biology, and §Department of Molecular Biophysics and Biochemistry, Yale University , New Haven, Connecticut 06520-8107, United States
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23
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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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24
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Amiram M, Haimovich AD, Fan C, Wang YS, Aerni HR, Ntai I, Moonan DW, Ma NJ, Rovner AJ, Hong SH, Kelleher NL, Goodman AL, Jewett MC, Söll D, Rinehart J, Isaacs FJ. Evolution of translation machinery in recoded bacteria enables multi-site incorporation of nonstandard amino acids. Nat Biotechnol 2015; 33:1272-1279. [PMID: 26571098 DOI: 10.1038/nbt.3372] [Citation(s) in RCA: 193] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Accepted: 09/11/2015] [Indexed: 01/24/2023]
Abstract
Expansion of the genetic code with nonstandard amino acids (nsAAs) has enabled biosynthesis of proteins with diverse new chemistries. However, this technology has been largely restricted to proteins containing a single or few nsAA instances. Here we describe an in vivo evolution approach in a genomically recoded Escherichia coli strain for the selection of orthogonal translation systems capable of multi-site nsAA incorporation. We evolved chromosomal aminoacyl-tRNA synthetases (aaRSs) with up to 25-fold increased protein production for p-acetyl-L-phenylalanine and p-azido-L-phenylalanine (pAzF). We also evolved aaRSs with tunable specificities for 14 nsAAs, including an enzyme that efficiently charges pAzF while excluding 237 other nsAAs. These variants enabled production of elastin-like-polypeptides with 30 nsAA residues at high yields (∼50 mg/L) and high accuracy of incorporation (>95%). This approach to aaRS evolution should accelerate and expand our ability to produce functionalized proteins and sequence-defined polymers with diverse chemistries.
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Affiliation(s)
- Miriam Amiram
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, Connecticut, USA.,Systems Biology Institute, Yale University, West Haven, Connecticut, USA
| | - Adrian D Haimovich
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, Connecticut, USA.,Systems Biology Institute, Yale University, West Haven, Connecticut, USA
| | - Chenguang Fan
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA
| | - Yane-Shih Wang
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA
| | - Hans-Rudolf Aerni
- Systems Biology Institute, Yale University, West Haven, Connecticut, USA.,Department of Cellular and Molecular Physiology, Yale University, New Haven, Connecticut, USA
| | - Ioanna Ntai
- Department of Chemistry, Northwestern University, Evanston, Illinois, USA
| | - Daniel W Moonan
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, Connecticut, USA.,Systems Biology Institute, Yale University, West Haven, Connecticut, USA
| | - Natalie J Ma
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, Connecticut, USA.,Systems Biology Institute, Yale University, West Haven, Connecticut, USA
| | - Alexis J Rovner
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, Connecticut, USA.,Systems Biology Institute, Yale University, West Haven, Connecticut, USA
| | - Seok Hoon Hong
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois, USA
| | - Neil L Kelleher
- Department of Chemistry, Northwestern University, Evanston, Illinois, USA
| | - Andrew L Goodman
- Department of Microbial Pathogenesis and Microbial Sciences Institute, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Michael C Jewett
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois, USA
| | - Dieter Söll
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA.,Department of Chemistry, Yale University, New Haven, Connecticut, USA
| | - Jesse Rinehart
- Systems Biology Institute, Yale University, West Haven, Connecticut, USA.,Department of Cellular and Molecular Physiology, Yale University, New Haven, Connecticut, USA
| | - Farren J Isaacs
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, Connecticut, USA.,Systems Biology Institute, Yale University, West Haven, Connecticut, USA
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25
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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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26
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On How Many Fundamental Kinds of Cells are Present on Earth: Looking for Phylogenetic Traits that Would Allow the Identification of the Primary Lines of Descent. J Mol Evol 2014; 78:313-20. [DOI: 10.1007/s00239-014-9626-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Accepted: 05/21/2014] [Indexed: 11/26/2022]
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27
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Fan C, Ho JML, Chirathivat N, Söll D, Wang YS. Exploring the substrate range of wild-type aminoacyl-tRNA synthetases. Chembiochem 2014; 15:1805-1809. [PMID: 24890918 DOI: 10.1002/cbic.201402083] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2014] [Indexed: 01/02/2023]
Abstract
We tested the substrate range of four wild-type E. coli aminoacyl-tRNA synthetases (AARSs) with a library of nonstandard amino acids (nsAAs). Although these AARSs could discriminate efficiently against the other canonical amino acids, they were able to use many nsAAs as substrates. Our results also show that E. coli tryptophanyl-tRNA synthetase (TrpRS) and tyrosyl-tRNA synthetase have overlapping substrate ranges. In addition, we found that the nature of the anticodon sequence of tRNA(Trp) altered the nsAA substrate range of TrpRS; this implies that the sequence of the anticodon affects the TrpRS amino acid binding pocket. These results highlight again that inherent AARS polyspecificity will be a major challenge in the aim of incorporating multiple different amino acids site-specifically into proteins.
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Affiliation(s)
- Chenguang Fan
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520 (USA)
| | - Joanne M L Ho
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520 (USA)
| | - Napon Chirathivat
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520 (USA)
| | - Dieter Söll
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520 (USA).,Department of Chemistry, Yale University, New Haven, CT 06520 (USA)
| | - Yane-Shih Wang
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520 (USA)
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28
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Schmidt MJ, Weber A, Pott M, Welte W, Summerer D. Structural basis of furan-amino acid recognition by a polyspecific aminoacyl-tRNA-synthetase and its genetic encoding in human cells. Chembiochem 2014; 15:1755-60. [PMID: 24737732 DOI: 10.1002/cbic.201402006] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Indexed: 11/05/2022]
Abstract
The site-selective introduction of photo-crosslinking groups into proteins enables the discovery and mapping of weak and/or transient protein interactions with high spatiotemporal resolution, both in vitro and in vivo. We report the genetic encoding of a furan-based, photo-crosslinking amino acid in human cells; it can be activated with red light, thus offering high penetration depths in biological samples. This is achieved by activation of the amino acid and charging to its cognate tRNA by a pyrrolysyl-tRNA-synthetase (PylRS) mutant with broad polyspecificity. To gain insights into the recognition of this amino acid and to provide a rationale for its polyspecificity, we solved three crystal structures of the PylRS mutant: in its apo-form, in complex with adenosine 5'-(β,γ-imido)triphosphate (AMP-PNP) and in complex with the AMP ester of the furan amino acid. These structures provide clues for the observed polyspecificity and represent a promising starting point for the engineering of PylRS mutants with further increased substrate scope.
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Affiliation(s)
- Moritz J Schmidt
- Department of Chemistry, University of Konstanz, Universitätsstrasse 10, 78457 Konstanz (Germany)
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29
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Wan W, Tharp JM, Liu WR. Pyrrolysyl-tRNA synthetase: an ordinary enzyme but an outstanding genetic code expansion tool. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2014; 1844:1059-70. [PMID: 24631543 DOI: 10.1016/j.bbapap.2014.03.002] [Citation(s) in RCA: 290] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Revised: 03/01/2014] [Accepted: 03/05/2014] [Indexed: 11/16/2022]
Abstract
The genetic incorporation of the 22nd proteinogenic amino acid, pyrrolysine (Pyl) at amber codon is achieved by the action of pyrrolysyl-tRNA synthetase (PylRS) together with its cognate tRNA(Pyl). Unlike most aminoacyl-tRNA synthetases, PylRS displays high substrate side chain promiscuity, low selectivity toward its substrate α-amine, and low selectivity toward the anticodon of tRNA(Pyl). These unique but ordinary features of PylRS as an aminoacyl-tRNA synthetase allow the Pyl incorporation machinery to be easily engineered for the genetic incorporation of more than 100 non-canonical amino acids (NCAAs) or α-hydroxy acids into proteins at amber codon and the reassignment of other codons such as ochre UAA, opal UGA, and four-base AGGA codons to code NCAAs.
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Affiliation(s)
- Wei Wan
- Department of Chemistry, Texas A&M University, College Station, TX 77845, USA
| | - Jeffery M Tharp
- Department of Chemistry, Texas A&M University, College Station, TX 77845, USA
| | - Wenshe R Liu
- Department of Chemistry, Texas A&M University, College Station, TX 77845, USA.
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