This paper describes the development of a new independent E. Coli strain JX 33 that allows to reassign the stop codon UAG into a sense codon, in order to facilitate the introduction of unnatural amino acids in live cells.
In JX33, the release factor 1 has been knocked-out to overcome the current issues associated with low level of incorporation. Also, their method can be used to incorporate several unnatural amino acids at different sites within the same protein. They tested the incorporation of up to 6 mutations in the EGFP gene and obtained similar level of fluorescence among all mutants.This is an interesting article. It may open up the possibility to introduce different unnatural amino acids within the same protein with high level of incorporation.
Our friendly competitor Lei Wang... Would be great if it would work for mammalian cells.
ReplyDeleteShe beat me to the post... pretty cool paper!
ReplyDeleteKnocking out RF1 seems an obvious route for improving incorporation of UAA's, I wonder why it took this long for someone to do it? Does this work for a broad range of UAA's?
ReplyDeleteI bet it does work with a broad range of UAAs... the RF factor shouldn't have much to do with the the specific UAA.
ReplyDeleteIt only recognizes the stop codon and either terminates or not depending on if the charged tRNA is present.
What is probably more difficult is repeating this scheme in Eukaryotes...eRF1 recognizes all three codons...