Скачать с ютуб How codon usage sets the pace in the race to translate в хорошем качестве

How codon usage sets the pace in the race to translate

OTHER VIDEOS YOU MIGHT LIKE: • Discovering mutagenic DNA polymerase IV in E. coli -    • Discovering mutagenic DNA polymerase ...   • Gene duplication: The formation of new genes… genes… genes -    • Gene duplication: The formation of ne...   • The discovery of nested genes: More than meets the fly -    • The discovery of nested genes: More t...   Translation is a complex biological process that happens all the time in our cells. Without it, we simply wouldn’t survive. Translation involves using mRNA to synthesise polypeptides which then fold into their tertiary forms. But did you know not all polypeptides are synthesised at the same rate? It turns out that the translation rate of a protein depends on the proportion of common and rare codons used in its open reading frame. Synonymous codons are codons that code for the same amino acid. Of these, common codons, which occur more frequently in a gene, usually have more tRNAs that recognise them in the cell, while rare codons, which occur less frequently in a gene, usually have fewer corresponding tRNAs. In 1989, Michael Sørensen and his colleagues pioneered the first experiment to measure the translation rate of an individual gene: the lacZ gene in E. coli. They refined a pulse-chase method developed by other researchers to measure the number of methionine amino acids incorporated into beta-galactosidase – the protein product of the lacZ gene – during its translation, then repeated this for six different versions of the gene in which they had added a range of common and rare codons. The results were striking! It was evident that rare codons were translated approximately six times slower than common codons. Researchers soon questioned why rare codons even existed if all they did was slow a protein’s translation rate down. This led to the advent of codon optimisation, a genetic engineering technique aiming to enhance protein production levels by replacing rare codons in a gene with synonymous common codons. However, there are indeed many reasons for a gene to use rare codons as well as common ones. Spoiler alert: it all links back to the survival of the organism! Creator: Marissa Chow References: Correlation between the abundance of Escherichia coli transfer RNAs and the occurrence of the respective codons in its protein genes: a proposal for a synonymous codon choice that is optimal for the E. coli translational system. Ikemura T. J Mol Biol. 1981 Sep 25;151(3):389-409. doi: 10.1016/0022-2836(81)90003-6. Escherichia coli ribosomes translate in vivo with variable rate. Pedersen S. EMBO J. 1984 Dec 1;3(12):2895-8. doi: 10.1002/j.1460-2075.1984.tb02227.x. Peptide chain growth of β-galactosidase in Escherichia coli. Lacroute F, Stent GS. J Mol Biol. 1968 Jul 14;35(1):165-73. doi: 10.1016/s0022-2836(68)80044-0. Analysis of the proteins synthesized in ultraviolet light-irradiated Escherichia coli following infection with the bacteriophages lambdadrifd 18 and lambdadfus-3. Pedersen S, Reeh SV. Mol Gen Genet. 1976 Mar 30;144(3):339-43. doi: 10.1007/BF00341733. Codon usage determines translation rate in Escherichia coli. Sørensen MA, Kurland CG, Pedersen S. J Mol Biol. 1989 May 20;207(2):365-77. doi: 10.1016/0022-2836(89)90260-x. Increased incidence of rare codon clusters at 5' and 3' gene termini: implications for function. Clarke TF 4th, Clark PL. BMC Genomics. 2010 Feb 18;11:118. doi: 10.1186/1471-2164-11-118. Synonymous codons direct cotranslational folding toward different protein conformations. Buhr F, Jha S, Thommen M, Mittelstaet J, Kutz F, Schwalbe H, Rodnina MV, Komar AA. Mol Cell. 2016;61(3):341-351. doi: 10.1016/j.molcel.2016.01.008. Protein secondary structural types are differentially coded on messenger RNA. Thanaraj TA, Argos P. Protein Sci. 1996 Oct;5(10):1973-83. doi: 10.1002/pro.5560051003. Synonymous codon substitutions affect ribosome traffic and protein folding during in vitro translation. Komar AA, Lesnik T, Reiss C. FEBS Lett. 1999 Dec 3;462(3):387-91. doi: 10.1016/s0014-5793(99)01566-5. Non-optimal codon usage affects expression, structure and function of clock protein FRQ. Zhou M, Guo J, Cha J, Chae M, Chen S, Barral JM, Sachs MS, Liu Y. Nature. 2013 Mar 7;495(7439):111-5. doi: 10.1038/nature11833.