A method to incorporate non-naturally occurring amino acids into proteins in mammalian cells is to be published online in Nature Methods. This is the first time the process has been successfully accomplished in mammalian cells and will allow scientists to 'custom make' proteins with new chemical properties useful for research, industry and medicine.
Protein synthesis is a three-step process in which the information encoded on the DNA is translated into a string of amino acids; first DNA is transcribed to mRNA, then enzymes - aminoacyl-tRNA synthetases - match each of the twenty naturally occurring amino acids with its corresponding transfer RNA (tRNA). The tRNAs then read the sequence on the mRNA and incorporate amino acids in the correct order into the growing protein.
Peter Schultz and colleagues changed an aminoacyl-tRNA synthetase in such a way that it paired the tRNA normally recognizing a stop codon - a sequence that terminates protein synthesis with an unnatural amino acid. Instead of terminating protein synthesis this tRNA now incorporates an unnatural amino acid into the protein with high fidelity and efficiency and without being toxic for the cells
Peter Schultz (Scripps Research Institute, La Jolla, CA, USA)
Michael Ibba (Ohio State University, Columbus, OH, USA)
(C) Nature Methods press release.
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