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Lee D, Kim JG, Kim TW, Choi JI. Development of orthogonal aminoacyl-tRNA synthetase mutant for incorporating a non-canonical amino acid. AMB Express 2024; 14:60. [PMID: 38782816 PMCID: PMC11116331 DOI: 10.1186/s13568-024-01706-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Accepted: 04/12/2024] [Indexed: 05/25/2024] Open
Abstract
Genetic code expansion involves introducing non-canonical amino acids (ncAAs) with unique functional groups into proteins to broaden their applications. Orthogonal aminoacyl tRNA synthetase (aaRS), essential for genetic code expansion, facilitates the charging of ncAAs to tRNA. In this study, we developed a new aaRS mutant from Methanosaeta concilii tyrosyl-tRNA synthetase (Mc TyrRS) to incorporate para-azido-L-phenylalanine (AzF). The development involved initial site-specific mutations in Mc TyrRS, followed by random mutagenesis. The new aaRS mutant with amber suppression was isolated through fluorescence-activated cell sorting. The M. concilii aaRS mutant structure was further analyzed to interpret the effect of mutations. This research provides a novel orthogonal aaRS evolution pipeline for highly efficient ncAA incorporation that will contribute to developing novel aaRS from various organisms.
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Affiliation(s)
- Dongheon Lee
- Department of Biotechnology and Bioengineering, Chonnam National University, Gwangju, 61186, Republic of Korea
| | - Ja Gyung Kim
- Department of Biotechnology and Bioengineering, Chonnam National University, Gwangju, 61186, Republic of Korea
| | - Tae Wan Kim
- Department of Biotechnology and Bioengineering, Chonnam National University, Gwangju, 61186, Republic of Korea.
| | - Jong-Il Choi
- Department of Biotechnology and Bioengineering, Chonnam National University, Gwangju, 61186, Republic of Korea.
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2
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Crystal Structure of an Archaeal Tyrosyl-tRNA Synthetase Bound to Photocaged L-Tyrosine and Its Potential Application to Time-Resolved X-ray Crystallography. Int J Mol Sci 2022; 23:ijms231810399. [PMID: 36142308 PMCID: PMC9499402 DOI: 10.3390/ijms231810399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 09/02/2022] [Accepted: 09/05/2022] [Indexed: 11/16/2022] Open
Abstract
Genetically encoded caged amino acids can be used to control the dynamics of protein activities and cellular localization in response to external cues. In the present study, we revealed the structural basis for the recognition of O-(2-nitrobenzyl)-L-tyrosine (oNBTyr) by its specific variant of Methanocaldococcus jannaschii tyrosyl-tRNA synthetase (oNBTyrRS), and then demonstrated its potential availability for time-resolved X-ray crystallography. The substrate-bound crystal structure of oNBTyrRS at a 2.79 Å resolution indicated that the replacement of tyrosine and leucine at positions 32 and 65 by glycine (Tyr32Gly and Leu65Gly, respectively) and Asp158Ser created sufficient space for entry of the bulky substitute into the amino acid binding pocket, while Glu in place of Leu162 formed a hydrogen bond with the nitro moiety of oNBTyr. We also produced an oNBTyr-containing lysozyme through a cell-free protein synthesis system derived from the Escherichia coli B95. ΔA strain with the UAG codon reassigned to the nonnatural amino acid. Another crystallographic study of the caged protein showed that the site-specifically incorporated oNBTyr was degraded to tyrosine by light irradiation of the crystals. Thus, cell-free protein synthesis of caged proteins with oNBTyr could facilitate time-resolved structural analysis of proteins, including medically important membrane proteins.
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Abstract
Within the broad field of synthetic biology, genetic code expansion (GCE) techniques enable creation of proteins with an expanded set of amino acids. This may be invaluable for applications in therapeutics, bioremediation, and biocatalysis. Central to GCE are aminoacyl-tRNA synthetases (aaRSs) as they link a non-canonical amino acid (ncAA) to their cognate tRNA, allowing ncAA incorporation into proteins on the ribosome. The ncAA-acylating aaRSs and their tRNAs should not cross-react with 20 natural aaRSs and tRNAs in the host, i.e., they need to function as an orthogonal translating system. All current orthogonal aaRS•tRNA pairs have been engineered from naturally occurring molecules to change the aaRS's amino acid specificity or assign the tRNA to a liberated codon of choice. Here we discuss the importance of orthogonality in GCE, laboratory techniques employed to create designer aaRSs and tRNAs, and provide an overview of orthogonal aaRS•tRNA pairs for GCE purposes.
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Affiliation(s)
- Natalie Krahn
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, United States
| | - Jeffery M Tharp
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, United States
| | - Ana Crnković
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, United States
| | - Dieter Söll
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, United States.
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Druart K, Palmai Z, Omarjee E, Simonson T. Protein:Ligand binding free energies: A stringent test for computational protein design. J Comput Chem 2015; 37:404-15. [PMID: 26503829 DOI: 10.1002/jcc.24230] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Revised: 10/01/2015] [Accepted: 10/02/2015] [Indexed: 01/29/2023]
Abstract
A computational protein design method is extended to allow Monte Carlo simulations where two ligands are titrated into a protein binding pocket, yielding binding free energy differences. These provide a stringent test of the physical model, including the energy surface and sidechain rotamer definition. As a test, we consider tyrosyl-tRNA synthetase (TyrRS), which has been extensively redesigned experimentally. We consider its specificity for its substrate l-tyrosine (l-Tyr), compared to the analogs d-Tyr, p-acetyl-, and p-azido-phenylalanine (ac-Phe, az-Phe). We simulate l- and d-Tyr binding to TyrRS and six mutants, and compare the structures and binding free energies to a more rigorous "MD/GBSA" procedure: molecular dynamics with explicit solvent for structures and a Generalized Born + Surface Area model for binding free energies. Next, we consider l-Tyr, ac- and az-Phe binding to six other TyrRS variants. The titration results are sensitive to the precise rotamer definition, which involves a short energy minimization for each sidechain pair to help relax bad contacts induced by the discrete rotamer set. However, when designed mutant structures are rescored with a standard GBSA energy model, results agree well with the more rigorous MD/GBSA. As a third test, we redesign three amino acid positions in the substrate coordination sphere, with either l-Tyr or d-Tyr as the ligand. For two, we obtain good agreement with experiment, recovering the wildtype residue when l-Tyr is the ligand and a d-Tyr specific mutant when d-Tyr is the ligand. For the third, we recover His with either ligand, instead of wildtype Gln.
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Affiliation(s)
- Karen Druart
- Laboratoire De Biochimie (UMR CNRS 7654), Department of Biology, Ecole Polytechnique, Palaiseau, France
| | - Zoltan Palmai
- Laboratoire De Biochimie (UMR CNRS 7654), Department of Biology, Ecole Polytechnique, Palaiseau, France
| | - Eyaz Omarjee
- Laboratoire De Biochimie (UMR CNRS 7654), Department of Biology, Ecole Polytechnique, Palaiseau, France
| | - Thomas Simonson
- Laboratoire De Biochimie (UMR CNRS 7654), Department of Biology, Ecole Polytechnique, Palaiseau, France
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Reichert AJ, Poxleitner G, Dauner M, Skerra A. Optimisation of a system for the co-translational incorporation of a keto amino acid and its application to a tumour-specific Anticalin. Protein Eng Des Sel 2015; 28:553-65. [DOI: 10.1093/protein/gzv048] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2015] [Accepted: 08/17/2015] [Indexed: 11/13/2022] Open
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Ren W, Truong TM, Ai HW. Study of the Binding Energies between Unnatural Amino Acids and Engineered Orthogonal Tyrosyl-tRNA Synthetases. Sci Rep 2015; 5:12632. [PMID: 26220470 PMCID: PMC4518261 DOI: 10.1038/srep12632] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 07/03/2015] [Indexed: 11/08/2022] Open
Abstract
We utilized several computational approaches to evaluate the binding energies of tyrosine (Tyr) and several unnatural Tyr analogs, to several orthogonal aaRSes derived from Methanocaldococcus jannaschii and Escherichia coli tyrosyl-tRNA synthetases. The present study reveals the following: (1) AutoDock Vina and ROSETTA were able to distinguish binding energy differences for individual pairs of favorable and unfavorable aaRS-amino acid complexes, but were unable to cluster together all experimentally verified favorable complexes from unfavorable aaRS-Tyr complexes; (2) MD-MM/PBSA provided the best prediction accuracy in terms of clustering favorable and unfavorable enzyme-substrate complexes, but also required the highest computational cost; and (3) MM/PBSA based on single energy-minimized structures has a significantly lower computational cost compared to MD-MM/PBSA, but still produced sufficiently accurate predictions to cluster aaRS-amino acid interactions. Although amino acid-aaRS binding is just the first step in a complex series of processes to acylate a tRNA with its corresponding amino acid, the difference in binding energy, as shown by MD-MM/PBSA, is important for a mutant orthogonal aaRS to distinguish between a favorable unnatural amino acid (unAA) substrate from unfavorable natural amino acid substrates. Our computational study should assist further designing and engineering of orthogonal aaRSes for the genetic encoding of novel unAAs.
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Affiliation(s)
- Wei Ren
- Department of Chemistry, University of California-Riverside, 501 Big Springs Road, Riverside, California 92521, United States
| | - Tan M. Truong
- Cell, Molecular, and Developmental Biology Graduate Program, University of California-Riverside, Riverside, California 92521, United States
| | - Hui-wang Ai
- Department of Chemistry, University of California-Riverside, 501 Big Springs Road, Riverside, California 92521, United States
- Cell, Molecular, and Developmental Biology Graduate Program, University of California-Riverside, Riverside, California 92521, United States
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Cooley RB, Feldman JL, Driggers CM, Bundy TA, Stokes AL, Karplus PA, Mehl RA. Structural basis of improved second-generation 3-nitro-tyrosine tRNA synthetases. Biochemistry 2014; 53:1916-24. [PMID: 24611875 PMCID: PMC3985459 DOI: 10.1021/bi5001239] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Genetic code expansion has provided the ability to site-specifically incorporate a multitude of noncanonical amino acids (ncAAs) into proteins for a wide variety of applications, but low ncAA incorporation efficiency can hamper the utility of this powerful technology. When investigating proteins containing the post-translational modification 3-nitro-tyrosine (nitroTyr), we developed second-generation amino-acyl tRNA synthetases (RS) that incorporate nitroTyr at efficiencies roughly an order of magnitude greater than those previously reported and that advanced our ability to elucidate the role of elevated cellular nitroTyr levels in human disease (e.g., Franco, M. et al. Proc. Natl. Acad. Sci. U.S.A 2013 , 110 , E1102 ). Here, we explore the origins of the improvement achieved in these second-generation RSs. Crystal structures of the most efficient of these synthetases reveal the molecular basis for the enhanced efficiencies observed in the second-generation nitroTyr-RSs. Although Tyr is not detectably incorporated into proteins when expression media is supplemented with 1 mM nitroTyr, a major difference between the first- and second-generation RSs is that the second-generation RSs have an active site more compatible with Tyr binding. This feature of the second-generation nitroTyr-RSs appears to be the result of using less stringent criteria when selecting from a library of mutants. The observation that a different selection strategy performed on the same library of mutants produced nitroTyr-RSs with dramatically improved efficiencies suggests the optimization of established selection protocols could lead to notable improvements in ncAA-RS efficiencies and thus the overall utility of this technology.
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Affiliation(s)
- Richard B Cooley
- Department of Biochemistry and Biophysics, Oregon State University , 2011 Agriculture and Life Sciences Building, Corvallis, Oregon 97331, United States
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Coin I, Katritch V, Sun T, Xiang Z, Siu FY, Beyermann M, Stevens RC, Wang L. Genetically encoded chemical probes in cells reveal the binding path of urocortin-I to CRF class B GPCR. Cell 2013; 155:1258-69. [PMID: 24290358 DOI: 10.1016/j.cell.2013.11.008] [Citation(s) in RCA: 140] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Revised: 08/26/2013] [Accepted: 11/07/2013] [Indexed: 01/19/2023]
Abstract
Molecular determinants regulating the activation of class B G-protein-coupled receptors (GPCRs) by native peptide agonists are largely unknown. We have investigated here the interaction between the corticotropin releasing factor receptor type 1 (CRF1R) and its native 40-mer peptide ligand Urocortin-I directly in mammalian cells. By incorporating unnatural amino acid photochemical and new click-chemical probes into the intact receptor expressed in the native membrane of live cells, 44 intermolecular spatial constraints have been derived for the ligand-receptor interaction. The data were analyzed in the context of the recently resolved crystal structure of CRF1R transmembrane domain and existing extracellular domain structures, yielding a complete conformational model for the peptide-receptor complex. Structural features of the receptor-ligand complex yield molecular insights on the mechanism of receptor activation and the basis for discrimination between agonist and antagonist function.
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Affiliation(s)
- Irene Coin
- Jack H. Skirball Center for Chemical Biology and Proteomics, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA
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Minnihan EC, Young DD, Schultz PG, Stubbe J. Incorporation of fluorotyrosines into ribonucleotide reductase using an evolved, polyspecific aminoacyl-tRNA synthetase. J Am Chem Soc 2011; 133:15942-5. [PMID: 21913683 PMCID: PMC3188361 DOI: 10.1021/ja207719f] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Tyrosyl radicals (Y·s) are prevalent in biological catalysis and are formed under physiological conditions by the coupled loss of both a proton and an electron. Fluorotyrosines (F(n)Ys, n = 1-4) are promising tools for studying the mechanism of Y· formation and reactivity, as their pK(a) values and peak potentials span four units and 300 mV, respectively, between pH 6 and 10. In this manuscript, we present the directed evolution of aminoacyl-tRNA synthetases (aaRSs) for 2,3,5-trifluorotyrosine (2,3,5-F(3)Y) and demonstrate their ability to charge an orthogonal tRNA with a series of F(n)Ys while maintaining high specificity over Y. An evolved aaRS is then used to incorporate F(n)Ys site-specifically into the two subunits (α2 and β2) of Escherichia coli class Ia ribonucleotide reductase (RNR), an enzyme that employs stable and transient Y·s to mediate long-range, reversible radical hopping during catalysis. Each of four conserved Ys in RNR is replaced with F(n)Y(s), and the resulting proteins are isolated in good yields. F(n)Ys incorporated at position 122 of β2, the site of a stable Y· in wild-type RNR, generate long-lived F(n)Y·s that are characterized by electron paramagnetic resonance (EPR) spectroscopy. Furthermore, we demonstrate that the radical pathway in the mutant Y(122)(2,3,5)F(3)Y-β2 is energetically and/or conformationally modulated in such a way that the enzyme retains its activity but a new on-pathway Y· can accumulate. The distinct EPR properties of the 2,3,5-F(3)Y· facilitate spectral subtractions that make detection and identification of new Y·s straightforward.
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Affiliation(s)
- Ellen C. Minnihan
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139
| | - Douglas D. Young
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037
| | - Peter G. Schultz
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037
| | - JoAnne Stubbe
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139
- Department of Biology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139
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Hutchins BM, Kazane SA, Staflin K, Forsyth JS, Felding-Habermann B, Schultz PG, Smider VV. Site-specific coupling and sterically controlled formation of multimeric antibody fab fragments with unnatural amino acids. J Mol Biol 2011; 406:595-603. [PMID: 21237172 PMCID: PMC4278757 DOI: 10.1016/j.jmb.2011.01.011] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2010] [Revised: 12/22/2010] [Accepted: 01/04/2011] [Indexed: 10/18/2022]
Abstract
Immunoconjugates and multispecific antibodies are rapidly emerging as highly potent experimental therapeutics against cancer. We have developed a method to incorporate an unnatural amino acid, p-acetylphenylalanine (pAcPhe) into an antibody antigen binding fragment (Fab) targeting HER2 (human epidermal growth factor receptor 2), allowing site-specific labeling without disrupting antigen binding. Expression levels of the pAcPhe-containing proteins were comparable to that of wild-type protein in shake-flask and fermentation preparations. The pAcPhe-Fabs were labeled by reaction with hydroxylamine dye and biotin species to produce well-defined, singly conjugated Fabs. We then coupled a hydroxylamine biotin to the pAcPhe-Fab and demonstrated controlled assembly of Fabs in the presence of the tetrameric biotin-binding protein, NeutrAvidin. The position of Fab biotinylation dictates the geometry of multimer assembly, producing unique multimeric Fab structures. These assembled Fab multimers differentially attenuate Her2 phosphorylation in breast cancer cells that overexpress the Her2 receptor. Thus, an encoded unnatural amino acid produces a chemical "handle" by which immunoconjugates and multimers can be engineered.
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Affiliation(s)
- Benjamin M. Hutchins
- Department of Chemistry and the Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Stephanie A. Kazane
- Department of Chemistry and the Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Karin Staflin
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Jane S. Forsyth
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Brunhilde Felding-Habermann
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Peter G. Schultz
- Department of Chemistry and the Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Vaughn V. Smider
- Department of Molecular Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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Young DD, Young TS, Jahnz M, Ahmad I, Spraggon G, Schultz PG. An evolved aminoacyl-tRNA synthetase with atypical polysubstrate specificity. Biochemistry 2011; 50:1894-900. [PMID: 21280675 DOI: 10.1021/bi101929e] [Citation(s) in RCA: 160] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
We have employed a rapid fluorescence-based screen to assess the polyspecificity of several aminoacyl-tRNA synthetases (aaRSs) against an array of unnatural amino acids. We discovered that a p-cyanophenylalanine specific aminoacyl-tRNA synthetase (pCNF-RS) has high substrate permissivity for unnatural amino acids, while maintaining its ability to discriminate against the 20 canonical amino acids. This orthogonal pCNF-RS, together with its cognate amber nonsense suppressor tRNA, is able to selectively incorporate 18 unnatural amino acids into proteins, including trifluoroketone-, alkynyl-, and halogen-substituted amino acids. In an attempt to improve our understanding of this polyspecificity, the X-ray crystal structure of the aaRS-p-cyanophenylalanine complex was determined. A comparison of this structure with those of other mutant aaRSs showed that both binding site size and other more subtle features control substrate polyspecificity.
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Affiliation(s)
- Douglas D Young
- Department of Chemistry and Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
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12
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Engineering of an Orthogonal Aminoacyl-tRNA Synthetase for Efficient Incorporation of the Non-natural Amino Acid O-Methyl-L-tyrosine using Fluorescence-based Bacterial Cell Sorting. J Mol Biol 2010; 404:70-87. [DOI: 10.1016/j.jmb.2010.09.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2010] [Revised: 08/14/2010] [Accepted: 09/01/2010] [Indexed: 11/18/2022]
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14
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Miyake-Stoner SJ, Refakis CA, Hammill JT, Lusic H, Hazen JL, Deiters A, Mehl RA. Generating permissive site-specific unnatural aminoacyl-tRNA synthetases. Biochemistry 2010; 49:1667-77. [PMID: 20082521 DOI: 10.1021/bi901947r] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Genetically incorporated unnatural amino acid (UAA) technologies are powerful tools that are greatly enhancing our ability to study and engineer biological systems. Using these techniques, researchers can precisely control the position and number of novel chemical moieties in a protein, via introducing the novel R group of UAAs, that are genetically encoded in the protein's primary structure. The substrate recognition properties of a natural aminoacyl-tRNA synthetase (aaRS) must be modified in order to incorporate UAAs into proteins. Protocols to do so are technically simple but require time and optimization, which has significantly limited the accessibility of this important technology. At present, engineered unnatural aminoacyl-tRNA synthetases (UaaRS) are evaluated on their translational efficiency (the extent to which they allow for incorporation of UAAs into protein) and fidelity (the extent to which they prevent incorporation of natural amino acids). We propose that a third parameter of substrate recognition, permissivity, is equally important. Permissive UaaRSs, whose relaxed substrate recognition properties allow them to incorporate multiple unnatural amino acids (but not natural amino acids), would eliminate the need to generate new UaaRSs for many new UAAs. Here, we outline methods for quickly and easily assessing the permissivity of existing UaaRSs and for generating permissive UaaRSs. In proof of principle experiments, we determined the degree of permissivity of two UaaRSs for a family of structurally related fluorinated UAAs ((19)F-UAAs). We then increased the permissivity of the initial UaaRSs to allow for incorporation of the family of (19)F-UAAs. Finally, we validated the utility of these new (19)F-UAAs as probes for fluorine NMR studies of protein structure and dynamics. We expect that results of this work will increase the accessibility of UAA technology and the use of new UAAs in proteins.
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Affiliation(s)
- Shigeki J Miyake-Stoner
- Department of Chemistry, Franklin & Marshall College, Lancaster, Pennsylvania 17604-3003, USA
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16
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Antonczak AK, Simova Z, Tippmann EM. A critical examination of Escherichia coli esterase activity. J Biol Chem 2009; 284:28795-800. [PMID: 19666472 DOI: 10.1074/jbc.m109.027409] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The ability of Escherichia coli to grow on a series of acetylated and glycosylated compounds has been investigated. It is surmised that E. coli maintains low levels of nonspecific esterase activity. This observation may have ramifications for previous reports that relied on nonspecific esterases from E. coli to genetically encode nonnatural amino acids. It had been reported that nonspecific esterases from E. coli deacetylate tri-acetyl O-linked glycosylated serine and threonine in vivo. The glycosylated amino acids were reported to have been genetically encoded into proteins in response to the amber stop codon. However, it is our contention that such amino acids are not utilized in this manner within E. coli. The current results report in vitro analysis of the original enzyme and an in vivo analysis of a glycosylated amino acid. It is concluded that the amber suppression method with nonnatural amino acids may require a caveat for use in certain instances.
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Affiliation(s)
- Alicja K Antonczak
- Cardiff University School of Chemistry, Cardiff CF10 3AT, United Kingdom
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Genetic Encoding of 3-Iodo-l-Tyrosine in Escherichia coli for Single-Wavelength Anomalous Dispersion Phasing in Protein Crystallography. Structure 2009; 17:335-44. [DOI: 10.1016/j.str.2009.01.008] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2008] [Revised: 01/15/2009] [Accepted: 01/15/2009] [Indexed: 11/21/2022]
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19
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Tippmann EM, Liu W, Summerer D, Mack AV, Schultz PG. A genetically encoded diazirine photocrosslinker in Escherichia coli. Chembiochem 2008; 8:2210-4. [PMID: 18000916 DOI: 10.1002/cbic.200700460] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Eric M Tippmann
- Department of Chemistry and the Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 N. Torrey Pines Rd, La Jolla, CA 92037, USA
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Xie J, Liu W, Schultz PG. A genetically encoded bidentate, metal-binding amino acid. Angew Chem Int Ed Engl 2008; 46:9239-42. [PMID: 17893898 DOI: 10.1002/anie.200703397] [Citation(s) in RCA: 122] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Jianming Xie
- Department of Chemistry and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 N. Torrey Pines Rd, La Jolla, CA 92037, USA
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Xie J, Liu W, Schultz P. A Genetically Encoded Bidentate, Metal-Binding Amino Acid. Angew Chem Int Ed Engl 2007. [DOI: 10.1002/ange.200703397] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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22
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Liu W, Alfonta L, Mack AV, Schultz PG. Structural Basis for the Recognition ofpara-Benzoyl-L-phenylalanine by Evolved Aminoacyl-tRNA Synthetases. Angew Chem Int Ed Engl 2007; 46:6073-5. [PMID: 17628477 DOI: 10.1002/anie.200701990] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Wenshe Liu
- Department of Chemistry and the Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 N. Torrey Pines Rd, La Jolla, CA 92037, USA
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Liu W, Alfonta L, Mack A, Schultz P. Structural Basis for the Recognition ofpara-Benzoyl-L-phenylalanine by Evolved Aminoacyl-tRNA Synthetases. Angew Chem Int Ed Engl 2007. [DOI: 10.1002/ange.200701990] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Xie J, Supekova L, Schultz PG. A genetically encoded metabolically stable analogue of phosphotyrosine in Escherichia coli. ACS Chem Biol 2007; 2:474-8. [PMID: 17622177 DOI: 10.1021/cb700083w] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
p-Carboxymethyl- l-phenylalanine (pCMF), a phosphotyrosine (pTyr) mimetic that is resistant to protein tyrosine phosphatase hydrolysis, was cotranslationally incorporated into proteins in Escherichia coli using an orthogonal amber suppressor tRNA/aminoacyl-tRNA synthetase (aaRS) pair. The pCMF-specific aaRS was identified from a large library of Methanococcus jannaschii tyrosyl-tRNA synthetase active-site mutants by a combination of positive and negative genetic selections. When pCMF was substituted for Tyr701 in human signal transducer and activator of transcription-1 (STAT1), a constitutively active mutant was obtained that dimerizes and binds a DNA oligonucleotide duplex that contains the M67 site recognized by Tyr701-phosphorylated STAT1. Genetic incorporation of pCMF into proteins should provide a new tool for the preparation of stable analogues of a wide array of phosphoproteins involved in signal transduction pathways, as well as the development of peptide-based, cellularly expressed inhibitors of pTyr binding proteins.
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Liu W, Brock A, Chen S, Chen S, Schultz PG. Genetic incorporation of unnatural amino acids into proteins in mammalian cells. Nat Methods 2007; 4:239-44. [PMID: 17322890 DOI: 10.1038/nmeth1016] [Citation(s) in RCA: 293] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2006] [Accepted: 01/22/2007] [Indexed: 11/09/2022]
Abstract
We developed a general approach that allows unnatural amino acids with diverse physicochemical and biological properties to be genetically encoded in mammalian cells. A mutant Escherichia coli aminoacyl-tRNA synthetase (aaRS) is first evolved in yeast to selectively aminoacylate its tRNA with the unnatural amino acid of interest. This mutant aaRS together with an amber suppressor tRNA from Bacillus stearothermophilus is then used to site-specifically incorporate the unnatural amino acid into a protein in mammalian cells in response to an amber nonsense codon. We independently incorporated six unnatural amino acids into GFP expressed in CHO cells with efficiencies up to 1 mug protein per 2 x 10(7) cells; mass spectrometry confirmed a high translational fidelity for the unnatural amino acid. This methodology should facilitate the introduction of biological probes into proteins for cellular studies and may ultimately facilitate the synthesis of therapeutic proteins containing unnatural amino acids in mammalian cells.
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Affiliation(s)
- Wenshe Liu
- Department of Chemistry and the Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 Torrey Pines Road, La Jolla, California 92037, USA
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Maloney DJ, Ghanem N, Zhou J, Hecht SM. Positional assignment of differentially substituted bisaminoacylated pdCpAs. Org Biomol Chem 2007; 5:3135-8. [PMID: 17878972 DOI: 10.1039/b708786a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The synthesis and NMR analysis of a 2'-O-alanyl, 3'-O-[1-(13)C]valyl-pdCpA derivative has permitted the definitive assignment of the positions of acylation of tandemly activated pdCpAs, and the bisaminoacylated transfer RNAs derived therefrom.
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Affiliation(s)
- David J Maloney
- Department of Chemistry, University of Virginia, Charlottesville, VA 22904, USA
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Abstract
Recently, a method to encode unnatural amino acids with diverse physicochemical and biological properties genetically in bacteria, yeast and mammalian cells was developed. Over 30 unnatural amino acids have been co-translationally incorporated into proteins with high fidelity and efficiency using a unique codon and corresponding transfer-RNA:aminoacyl-tRNA-synthetase pair. This provides a powerful tool for exploring protein structure and function in vitro and in vivo, and for generating proteins with new or enhanced properties.
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Affiliation(s)
- Jianming Xie
- Department of Chemistry and Skaggs Institute for Chemical Biology, the Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, USA
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28
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Abstract
Recently, a general method was developed that makes it possible to genetically encode unnatural amino acids with diverse physical, chemical, or biological properties in Escherichia coli, yeast, and mammalian cells. More than 30 unnatural amino acids have been incorporated into proteins with high fidelity and efficiency by means of a unique codon and corresponding tRNA/aminoacyl-tRNA synthetase pair. These include fluorescent, glycosylated, metal-ion-binding, and redox-active amino acids, as well as amino acids with unique chemical and photochemical reactivity. This methodology provides a powerful tool both for exploring protein structure and function in vitro and in vivo and for generating proteins with new or enhanced properties.
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Affiliation(s)
- Lei Wang
- The Jack H. Skirball Center for Chemical Biology & Proteomics, The Salk Institute for Biological Studies, La Jolla, California 92037, USA
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29
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Turner JM, Graziano J, Spraggon G, Schultz PG. Structural plasticity of an aminoacyl-tRNA synthetase active site. Proc Natl Acad Sci U S A 2006; 103:6483-8. [PMID: 16618920 PMCID: PMC1458910 DOI: 10.1073/pnas.0601756103] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Recently, tRNA aminoacyl-tRNA synthetase pairs have been evolved that allow one to genetically encode a large array of unnatural amino acids in both prokaryotic and eukaryotic organisms. We have determined the crystal structures of two substrate-bound Methanococcus jannaschii tyrosyl aminoacyl-tRNA synthetases that charge the unnatural amino acids p-bromophenylalanine and 3-(2-naphthyl)alanine (NpAla). A comparison of these structures with the substrate-bound WT synthetase, as well as a mutant synthetase that charges p-acetylphenylalanine, shows that altered specificity is due to both side-chain and backbone rearrangements within the active site that modify hydrogen bonds and packing interactions with substrate, as well as disrupt the alpha8-helix, which spans the WT active site. The high degree of structural plasticity that is observed in these aminoacyl-tRNA synthetases is rarely found in other mutant enzymes with altered specificities and provides an explanation for the surprising adaptability of the genetic code to novel amino acids.
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Affiliation(s)
- James M. Turner
- *Department of Chemistry and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037; and
| | - James Graziano
- *Department of Chemistry and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037; and
| | - Glen Spraggon
- Genomics Institute of the Novartis Research Foundation, 10675 John Jay Hopkins Drive, San Diego, CA 92121
| | - Peter G. Schultz
- *Department of Chemistry and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037; and
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Xie J, Schultz PG. Adding amino acids to the genetic repertoire. Curr Opin Chem Biol 2005; 9:548-54. [PMID: 16260173 DOI: 10.1016/j.cbpa.2005.10.011] [Citation(s) in RCA: 151] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2005] [Accepted: 10/12/2005] [Indexed: 11/23/2022]
Abstract
Considerable progress has been made in expanding the number and nature of genetically encoded amino acids in Escherichia coli, yeast and mammalian cells in the past four years. To date, over 30 unnatural amino acids have been cotranslationally incorporated into proteins with high fidelity and efficiency by means of a unique codon and corresponding orthogonal tRNA-aminoacyl-tRNA synthetase pair. The incorporated amino acids contain spectroscopic probes, post-translational modifications, metal chelators, photoaffinity labels and unique functional groups. The ability to genetically encode additional amino acids, beyond the common 20, provides a powerful approach for probing protein structure and function both in vitro and in vivo, as well as generating proteins with new or enhanced properties.
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Affiliation(s)
- Jianming Xie
- Department of Chemistry and Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
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