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- Choi, Junhong, et al.
(författare)
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2'-O-methylation in mRNA disrupts tRNA decoding during translation elongation
- 2018
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Ingår i: Nature Structural & Molecular Biology. - : Springer Nature. - 1545-9993 .- 1545-9985. ; 25:3, s. 208-216
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Tidskriftsartikel (refereegranskat)abstract
- Chemical modifications of mRNA may regulate many aspects of mRNA processing and protein synthesis. Recently, 2 '-O-methylation of nucleotides was identified as a frequent modification in translated regions of human mRNA, showing enrichment in codons for certain amino acids. Here, using single-molecule, bulk kinetics and structural methods, we show that 2 '-O-methylation within coding regions of mRNA disrupts key steps in codon reading during cognate tRNA selection. Our results suggest that 2 '-O-methylation sterically perturbs interactions of ribosomal-monitoring bases (G530, A1492 and A1493) with cognate codon-anticodon helices, thereby inhibiting downstream GTP hydrolysis by elongation factor Tu (EF-Tu) and A-site tRNA accommodation, leading to excessive rejection of cognate aminoacylated tRNAs in initial selection and proofreading. Our current and prior findings highlight how chemical modifications of mRNA tune the dynamics of protein synthesis at different steps of translation elongation.
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| 2. |
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| 3. |
- Wang, Jinfan, et al.
(författare)
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Ribosomal incorporation of unnatural amino acids : lessons and improvements from fast kinetics studies
- 2018
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Ingår i: Current opinion in chemical biology. - : Elsevier. - 1367-5931 .- 1879-0402. ; 46, s. 180-187
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Forskningsöversikt (refereegranskat)abstract
- Technologies for genetically programming ribosomal incorporation of unnatural amino acids are expanding and have created many exciting applications. However, these applications are generally limited by low efficiencies of the unnatural incorporations. Here we review our current mechanistic understanding of these limitations delineated from in vitro fast kinetics. Rate limitation occurs by different mechanisms, depending on the classes of the unnatural amino acids and the tRNA adaptors. This new understanding has led to several ways of improving the incorporation efficiencies, as well as challenges of dogma on rate-limiting steps in protein synthesis in natural cells.
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