A single mutation in yeast ribosomes triples unnatural amino acid incorporation.

Cells build proteins using twenty standard building blocks called amino acids. Scientists can add custom, noncanonical amino acids into proteins, but this process works poorly in complex cells like yeast. To fix this, researchers built a visual screening system to evolve 18S ribosomal DNA in yeast. Ribosomes are the cell's protein-building machines. By mutating this DNA, the team created modified ribosomes that read genetic instructions and insert the custom amino acids more effectively. Their best strain, called ribo-hyper, boosted target protein production by 2.9-fold compared to normal cells. This strain worked across different translation tool pairs. Although it slightly slowed yeast growth and overall protein production, the altered ribosome successfully showed that engineering eukaryotic ribosomes improves custom protein synthesis.

Why it matters

Scientists can now build proteins with unnatural building blocks, useful for making new medicines or studying cells. But in yeast and other complex cells, the process is too inefficient for many applications. This work shows that tweaking the ribosome itself can dramatically boost efficiency, opening the door to more practical use of these designer proteins.

Questions answered