A New Functional Suppressor tRNA/Aminoacyl−tRNA Synthetase Pair for the in Vivo Incorporation of Unnatural Amino Acids into Proteins

2000 ◽  
Vol 122 (20) ◽  
pp. 5010-5011 ◽  
Author(s):  
Lei Wang ◽  
Thomas J. Magliery ◽  
David R. Liu ◽  
Peter G. Schultz
Biomolecules ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 255 ◽  
Author(s):  
Sviatlana Smolskaya ◽  
Yaroslav Andreev

More than two decades ago a general method to genetically encode noncanonical or unnatural amino acids (NAAs) with diverse physical, chemical, or biological properties in bacteria, yeast, animals and mammalian cells was developed. More than 200 NAAs have been incorporated into recombinant proteins by means of non-endogenous aminoacyl-tRNA synthetase (aa-RS)/tRNA pair, an orthogonal pair, that directs site-specific incorporation of NAA encoded by a unique codon. The most established method to genetically encode NAAs in Escherichia coli is based on the usage of the desired mutant of Methanocaldococcus janaschii tyrosyl-tRNA synthetase (MjTyrRS) and cognate suppressor tRNA. The amber codon, the least-used stop codon in E. coli, assigns NAA. Until very recently the genetic code expansion technology suffered from a low yield of targeted proteins due to both incompatibilities of orthogonal pair with host cell translational machinery and the competition of suppressor tRNA with release factor (RF) for binding to nonsense codons. Here we describe the latest progress made to enhance nonsense suppression in E. coli with the emphasis on the improved expression vectors encoding for an orthogonal aa-RA/tRNA pair, enhancement of aa-RS and suppressor tRNA efficiency, the evolution of orthogonal EF-Tu and attempts to reduce the effect of RF1.


2016 ◽  
Author(s):  
Ximena Steinberg ◽  
Jason Galpin ◽  
Gibran Nasir ◽  
Jose Sepulveda-Ugarte ◽  
Romina V. Sepúlveda ◽  
...  

AbstractThe incorporation of non-canonical amino acids into proteins has emerged as a promising strategy to manipulate and study protein structure-function relationships with superior precision in vitro and in vivo. To date, fluorescent non-canonical amino acids (f-ncAA) have been successfully incorporated in proteins expressed in bacterial systems, Xenopus oocytes, and HEK-293T cells. Here, we describe the rational generation of an orthogonal aminoacyltRNA synthetase based on the E. coli tyrosine synthetase that is capable of encoding the f-ncAA tyr-coumarin in HEK-293T cells.


2013 ◽  
Vol 12 (6) ◽  
pp. 816-827 ◽  
Author(s):  
Silke Palzer ◽  
Yannick Bantel ◽  
Franziska Kazenwadel ◽  
Michael Berg ◽  
Steffen Rupp ◽  
...  

ABSTRACT For novel insights into the pathogenicity of Candida albicans , studies on molecular interactions of central virulence factors are crucial. Since methods for the analysis of direct molecular interactions of proteins in vivo are scarce, we expanded the genetic code of C. albicans with the synthetic photo-cross-linking amino acid p -azido- l -phenylalanine (AzF). Interacting molecules in close proximity of this unnatural amino acid can be covalently linked by UV-induced photo-cross-link, which makes unknown interacting molecules available for downstream identification. Therefore, we applied an aminoacyl-tRNA synthetase and a suppressor tRNA pair ( Ec TyrtRNA CUA ) derived from Escherichia coli , which was previously reported to be orthogonal in Saccharomyces cerevisiae . We further optimized the aminoacyl-tRNA synthetase for AzF (AzF-RS) and Ec TyrtRNA CUA for C. albicans and identified one AzF-RS with highest charging efficiency. Accordingly, incorporation of AzF into selected model proteins such as Tsa1p or Tup1p could be considerably enhanced. Immunologic detection of C-terminally tagged Tsa1p and Tup1p upon UV irradiation in a strain background containing suppressor tRNA and optimized AzF-RS revealed not only the mutant monomeric forms of these proteins but also higher-molecular-weight complexes, strictly depending on the specific position of incorporated AzF and UV excitation. By Western blotting and tandem mass spectrometry, we could identify these higher-molecular-weight complexes as homodimers consisting of one mutant monomer and a differently tagged, wild-type version of Tsa1p or Tup1p, respectively, demonstrating that expanding the genetic code of C. albicans with the unnatural photo-cross-linker amino acid AzF and applying it for in vivo binary protein interaction analyses is feasible.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Hongxia Zhao ◽  
Wenlong Ding ◽  
Jia Zang ◽  
Yang Yang ◽  
Chao Liu ◽  
...  

AbstractSite-specific incorporation of unnatural amino acids (UAAs) with similar incorporation efficiency to that of natural amino acids (NAAs) and low background activity is extremely valuable for efficient synthesis of proteins with diverse new chemical functions and design of various synthetic auxotrophs. However, such efficient translation systems remain largely unknown in the literature. Here, we describe engineered chimeric phenylalanine systems that dramatically increase the yield of proteins bearing UAAs, through systematic engineering of the aminoacyl-tRNA synthetase and its respective cognate tRNA. These engineered synthetase/tRNA pairs allow single-site and multi-site incorporation of UAAs with efficiencies similar to those of NAAs and high fidelity. In addition, using the evolved chimeric phenylalanine system, we construct a series of E. coli strains whose growth is strictly dependent on exogenously supplied of UAAs. We further show that synthetic auxotrophic cells can grow robustly in living mice when UAAs are supplemented.


2004 ◽  
Vol 279 (19) ◽  
pp. 19839-19845 ◽  
Author(s):  
Thomas Bentin ◽  
Ramin Hamzavi ◽  
Johan Salomonsson ◽  
Hervé Roy ◽  
Michael Ibba ◽  
...  

Unnatural amino acids carrying reactive groups that can be selectively activated under non-invasive biologically benign conditions are of interest in protein engineering as biological tools for the analysis of protein-protein and protein-nucleic acids interactions. The double ring system phenylalanine analogues benzofuranylalanine and benzotriazolylalanine were synthesized, and their photolability was tested by UV irradiation at 254, 320, and 365 nm. Although both showed photo reactivity, benzofuranylalanine appeared as the most promising compound because this amino acid was activated by UVA (long wavelength) irradiation. These amino acids were also tested forin vitrocharging of tRNAPheand for protein mutagenesis via the phenylalanyl-tRNA synthetase variant αA294G that is able to facilitatein vivoprotein synthesis using a range ofpara-substituted phenylalanine analogues. The results demonstrate that benzofuranylalanine, but not benzotriazolylalanine, is a substrate for phenylalanine tRNA synthetase αA294G, and matrix-assisted laser desorption ionization time-of-flight analysis showed it to be incorporated into a model protein with high efficiency. Thein vivoincorporation into a target protein of a bicyclic phenylalanine analogue, as described here, demonstrates the applicability of phenylalanine tRNA synthetase variants in expanding the scope of protein engineering.


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