Figure 4.

For incorporation of non-natural amino acids, amber-suppressing tRNAs are used. A strain having RF1 would create a competition between amber suppression tRNA and RF1 to bind with site-specific amber codon, which is represented in the figure. To avoid this competitive binding, cell extract is prepared using a strain lacking RF1. Figure reproduced with permission from Schoborg and Jewett (2018) © John Wiley and Sons, Inc.