The pyrrolysyl-tRNA/pyrrolysyl-tRNA synthetase (PylT/RS) pair from the archaeon Methanosarcina mazei (Mma) is widely used in protein engineering to site-specifically introduce noncanonical amino acids (ncAAs) through nonsense codon suppression. Here, we engineer the PylT/RS pair encoded by Methanogenic archaeon ISO4-G1 (G1) to be orthogonal to Mma PylT/RS and alter the G1 PylRS active site to accept a complementary ncAA spectrum. We combine the resulting mutual orthogonal pairs for site-specific dual ncAA incorporation of two lysine analogs with high selectivity and efficiency. Demonstrating the robustness of the system, we incorporate two ncAAs with compatible bioorthogonal reactivity into a Notch receptor, as well as a G protein-coupled receptor. We show that selective and site-specific incorporation of two ncAAs allows for two-color bioorthogonal labeling as well as chemical-controlled crosslinking of surface proteins on live mammalian cells.
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http://dx.doi.org/10.1016/j.celrep.2020.107811 | DOI Listing |
Environ Toxicol Chem
January 2025
ARCHE Consulting, Ghent, Belgium.
This study aimed to develop a bioavailability-based effects assessment method for nickel (Ni) to derive acute freshwater environmental thresholds in Europe. The authors established a reliable acute freshwater Ni ecotoxicity database covering 63 different freshwater species, and the existing acute Ni bioavailability models for invertebrates were revised. A single average invertebrate bioavailability model was proposed, in which the protective effects of Ca2+ and Mg2+ on Ni2+ toxicity were integrated as a single-site competition effect at the Ni biotic ligand.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Department of Polymer Chemistry and Technology, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia.
Polyethers are versatile materials extensively used in advanced as well as everyday applications. The incorporation of primary amine functionality into polyethers is particularly attractive due to its well-established coupling chemistries. However, the inherent nucleophilicity of amine group poses a challenge in the anionic ring-opening polymerization (ROP) of epoxides and requires the use of robust protecting groups that can withstand the harsh conditions of ROP without triggering undesirable side reactions.
View Article and Find Full Text PDFChembiochem
January 2025
Peking University, College of Chemistry and Molecular Engineering, No. 292 Chengfu Road, Haidian District, 100871, Beijing, CHINA.
Since the building blocks of DNA are nonfluorescent, various external fluorescence reporters have been employed to investigate the structure, dynamics, and function of DNA G-quadruplexes (GQs) and i-motifs (iMs), which play an important role in gene regulation and expression. However, most of those fluorescence reporters lack the ability to provide site-specific structural information of interest. Therefore, it is necessary to develop fluorescent nucleoside analogues that can be covalently inserted into oligonucleotides, which not only serve this purpose, but minimize any potential perturbation towards the native structure of the DNA systems in question.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Nanjing University, State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, CHINA.
Targeted degradation of membrane proteins represents an attractive strategy for eliminating pathogenesis-related proteins. Aptamer-based chimeras hold great promise as membrane protein degraders, however, their degradation efficacy is often hindered by the limited structural stability and the risk of off-target effects due to the non-covalent interaction with target proteins. We here report the first design of a covalent aptamer-based autophagosome-tethering chimera (CApTEC) for the enhanced autophagic degradation of cell-surface proteins, including transferrin receptor 1 (TfR1) and nucleolin (NCL).
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Boston College, Chemistry, 2609 Beacon Street, 201 Merkert Chemistry Center, 02467, Chestnut hill, UNITED STATES OF AMERICA.
Site-specific incorporation of noncanonical amino acids (ncAAs) into proteins in eukaryotes has predominantly relied on the pyrrolysyl-tRNA synthetase/tRNA pair. However, access to additional easily engineered pairs is crucial for expanding the structural diversity of the ncAA toolbox in eukaryotes. The Escherichia coli-derived leucyl-tRNA synthetase (EcLeuRS)/tRNA pair presents a particularly promising alternative.
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