Genetic Code Expansion inRhodobacter sphaeroidesto Incorporate Noncanonical Amino Acids into Photosynthetic Reaction Centers

2018 ◽  
Vol 7 (6) ◽  
pp. 1618-1628 ◽  
Author(s):  
Jared Bryce Weaver ◽  
Steven G. Boxer
Keyword(s):  
Amino Acids ◽  
Genetic Code ◽  
Reaction Centers ◽  
Photosynthetic Reaction Centers ◽  
Noncanonical Amino Acids ◽  
Genetic Code Expansion

scholarly journals Evolving Bacterial Fitness with an Expanded Genetic Code

2017 ◽  
Author(s):  
Drew S. Tack ◽  
Austin C. Cole ◽  
R. Shroff ◽  
B.R. Morrow ◽  
Andrew D. Ellington
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Genetic Code ◽  
Unnatural Amino Acid ◽  
Noncanonical Amino Acids ◽  
Bacterial Fitness ◽  
Genetic Code Expansion ◽  
Encoding Strategy ◽  
Translation Systems ◽  
Expanded Genetic Code

AbstractEvolution has for the most part used the canonical 20 amino acids of the natural genetic code to construct proteins. While several theories regarding the evolution of the genetic code have been proposed, experimental exploration of these theories has largely been restricted to phylogenetic and computational modeling. The development of orthogonal translation systems has allowed noncanonical amino acids to be inserted at will into proteins. We have taken advantage of these advances to evolve bacteria to accommodate a 21 amino acid genetic code in which the amber codon ambiguously encodes either 3-nitro-L-tyrosine or stop. Such an ambiguous encoding strategy recapitulates numerous models for genetic code expansion, and we find that evolved lineages first accommodate the unnatural amino acid, and then begin to evolve on a neutral landscape where stop codons begin to appear within genes. The resultant lines represent transitional intermediates on the way to the fixation of a functional 21 amino acid code.

scholarly journals Transferability of N-terminal mutations of pyrrolysyl-tRNA synthetase in one species to that in another species on unnatural amino acid incorporation efficiency

Amino Acids ◽  
2020 ◽  
Author(s):  
Thomas L. Williams ◽  
Debra J. Iskandar ◽  
Alexander R. Nödling ◽  
Yurong Tan ◽  
Louis Y. P. Luk ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Genetic Code ◽  
Unnatural Amino Acids ◽  
Trna Synthetase ◽  
Unnatural Amino Acid ◽  
Amino Acid Incorporation ◽  
Acid Incorporation ◽  
Genetic Code Expansion ◽  
Incorporation Efficiency

AbstractGenetic code expansion is a powerful technique for site-specific incorporation of an unnatural amino acid into a protein of interest. This technique relies on an orthogonal aminoacyl-tRNA synthetase/tRNA pair and has enabled incorporation of over 100 different unnatural amino acids into ribosomally synthesized proteins in cells. Pyrrolysyl-tRNA synthetase (PylRS) and its cognate tRNA from Methanosarcina species are arguably the most widely used orthogonal pair. Here, we investigated whether beneficial effect in unnatural amino acid incorporation caused by N-terminal mutations in PylRS of one species is transferable to PylRS of another species. It was shown that conserved mutations on the N-terminal domain of MmPylRS improved the unnatural amino acid incorporation efficiency up to five folds. As MbPylRS shares high sequence identity to MmPylRS, and the two homologs are often used interchangeably, we examined incorporation of five unnatural amino acids by four MbPylRS variants at two temperatures. Our results indicate that the beneficial N-terminal mutations in MmPylRS did not improve unnatural amino acid incorporation efficiency by MbPylRS. Knowledge from this work contributes to our understanding of PylRS homologs which are needed to improve the technique of genetic code expansion in the future.

scholarly journals Making Sense of “Nonsense” and More: Challenges and Opportunities in the Genetic Code Expansion, in the World of tRNA Modifications

2022 ◽  
Vol 23 (2) ◽  
pp. 938
Author(s):  
Olubodun Michael Lateef ◽  
Michael Olawale Akintubosun ◽  
Olamide Tosin Olaoba ◽  
Sunday Ocholi Samson ◽  
Malgorzata Adamczyk
Keyword(s):  
Amino Acids ◽  
Genetic Code ◽  
Protein Design ◽  
Side Chains ◽  
Vast Number ◽  
Trna Modifications ◽  
Wide Range ◽  
Challenges And Opportunities ◽  
Code Extension ◽  
Genetic Code Expansion

The evolutional development of the RNA translation process that leads to protein synthesis based on naturally occurring amino acids has its continuation via synthetic biology, the so-called rational bioengineering. Genetic code expansion (GCE) explores beyond the natural translational processes to further enhance the structural properties and augment the functionality of a wide range of proteins. Prokaryotic and eukaryotic ribosomal machinery have been proven to accept engineered tRNAs from orthogonal organisms to efficiently incorporate noncanonical amino acids (ncAAs) with rationally designed side chains. These side chains can be reactive or functional groups, which can be extensively utilized in biochemical, biophysical, and cellular studies. Genetic code extension offers the contingency of introducing more than one ncAA into protein through frameshift suppression, multi-site-specific incorporation of ncAAs, thereby increasing the vast number of possible applications. However, different mediating factors reduce the yield and efficiency of ncAA incorporation into synthetic proteins. In this review, we comment on the recent advancements in genetic code expansion to signify the relevance of systems biology in improving ncAA incorporation efficiency. We discuss the emerging impact of tRNA modifications and metabolism in protein design. We also provide examples of the latest successful accomplishments in synthetic protein therapeutics and show how codon expansion has been employed in various scientific and biotechnological applications.

Rational design of a function-based selection method for genetically encoding acylated lysine derivatives

2019 ◽  
Vol 17 (25) ◽  
pp. 6127-6130
Author(s):  
Hui Miao ◽  
Chenguang Yu ◽  
Anzhi Yao ◽  
Weimin Xuan
Keyword(s):  
Amino Acids ◽  
Genetic Code ◽  
Directed Evolution ◽  
Rational Design ◽  
Selection Method ◽  
Genetic Code Expansion

Genetic code expansion depends on the directed evolution of aaRS to recognize non-canonical amino acids. Herein, we reported a function-based method that enables rapidly evolving aaRS for acylated lysine derivatives.

scholarly journals The Role of Orthogonality in Genetic Code Expansion

Life ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 58 ◽  
Author(s):  
Pol Arranz-Gibert ◽  
Jaymin R. Patel ◽  
Farren J. Isaacs
Keyword(s):  
Gene Expression ◽  
Amino Acids ◽  
Genetic Code ◽  
Cross Reactivity ◽  
Elongation Factors ◽  
Translational Machinery ◽  
Trna Synthetases ◽  
Aminoacyl Trna Synthetases ◽  
Genetic Code Expansion

The genetic code defines how information in the genome is translated into protein. Aside from a handful of isolated exceptions, this code is universal. Researchers have developed techniques to artificially expand the genetic code, repurposing codons and translational machinery to incorporate nonstandard amino acids (nsAAs) into proteins. A key challenge for robust genetic code expansion is orthogonality; the engineered machinery used to introduce nsAAs into proteins must co-exist with native translation and gene expression without cross-reactivity or pleiotropy. The issue of orthogonality manifests at several levels, including those of codons, ribosomes, aminoacyl-tRNA synthetases, tRNAs, and elongation factors. In this concept paper, we describe advances in genome recoding, translational engineering and associated challenges rooted in establishing orthogonality needed to expand the genetic code.

scholarly journals High-throughput aminoacyl-tRNA synthetase engineering for genetic code expansion in yeast

2021 ◽  
Author(s):  
Jessica T. Stieglitz ◽  
James A. Van Deventer
Keyword(s):  
Genetic Code ◽  
High Throughput ◽  
Trna Synthetase ◽  
Noncanonical Amino Acids ◽  
Trna Synthetases ◽  
E Coli ◽  
Biological Studies ◽  
Screening Strategies ◽  
Genetic Code Expansion ◽  
Translation Systems

Protein expression with genetically encoded noncanonical amino acids (ncAAs) benefits a broad range of applications, from the discovery of biological therapeutics to fundamental biological studies. A major factor limiting the use of ncAAs is the lack of orthogonal translation systems (OTSs) that support efficient genetic code expansion at repurposed stop codons. Aminoacyl-tRNA synthetases (aaRSs) have been extensively evolved in E. coli but are not always orthogonal in eukaryotes. In this work, we use a yeast display-based ncAA incorporation reporter platform with fluorescence-activated cell sorting (FACS) to screen libraries of aaRSs in high throughput for 1) incorporation of ncAAs not previously encoded in yeast; 2) improvement of the performance of an existing aaRS; 3) highly selective OTSs capable of discriminating between closely related ncAA analogs; and 4) OTSs exhibiting enhanced polyspecificity to support translation with structurally diverse sets of ncAAs. The number of previously undiscovered aaRS variants we report in this work more than doubles the total number of translationally active aaRSs available for genetic code manipulation in yeast. The success of myriad screening strategies has important implications related to the fundamental properties and evolvability of aaRSs. Furthermore, access to OTSs with diverse activities and specific/polyspecific properties are invaluable for a range of applications within chemical biology, synthetic biology, and protein engineering.

scholarly journals Genetically Encoded Libraries of Nonstandard Peptides

2012 ◽  
Vol 2012 ◽  
pp. 1-15 ◽  
Author(s):  
Takashi Kawakami ◽  
Hiroshi Murakami
Keyword(s):  
Amino Acids ◽  
Genetic Code ◽  
Posttranslational Modifications ◽  
Biological Properties ◽  
Peptide Libraries ◽  
Universal Genetic Code ◽  
Nonsense Codons ◽  
Genetic Code Expansion ◽  
Diagnostic Applications ◽  
Selection Of

The presence of a nonproteinogenic moiety in a nonstandard peptide often improves the biological properties of the peptide. Non-standard peptide libraries are therefore used to obtain valuable molecules for biological, therapeutic, and diagnostic applications. Highly diverse non-standard peptide libraries can be generated by chemically or enzymatically modifying standard peptide libraries synthesized by the ribosomal machinery, using posttranslational modifications. Alternatively, strategies for encoding non-proteinogenic amino acids into the genetic code have been developed for the direct ribosomal synthesis of non-standard peptide libraries. In the strategies for genetic code expansion, non-proteinogenic amino acids are assigned to the nonsense codons or 4-base codons in order to add these amino acids to the universal genetic code. In contrast, in the strategies for genetic code reprogramming, some proteinogenic amino acids are erased from the genetic code and non-proteinogenic amino acids are reassigned to the blank codons. Here, we discuss the generation of genetically encoded non-standard peptide libraries using these strategies and also review recent applications of these libraries to the selection of functional non-standard peptides.

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