Introduction and Methods

The purpose of this work was to determine whether we should codon optimize the genes from Nitrosomonas europaea and Pseudomonas aeruginosa that we are expressing in E. coli. We found that the heterologous expression of these genes was such that we did not need to codon optimize.

E. coli has a different tRNA pool than N. europaea and P. aeruginosa. When genes from these organisms are expressed in E. coli, they may have a very inefficient translation efficiency if the available tRNA pools are different.

Using tRNAscan-SE 1.4, we determined the codon tables for E. coli, N. europaea and P. aeruginosa. Then, we calculated the tRNA adaptation index for each organism using a script provided by Chris Workman (unpublished). Finally, we calculated the heterologous expression of our genes of interest from N. europaea and P. aeruginosa in E. coli (using the E. coli translation table).

Results